© Ron Mahabalsingh 2015 - THE SCIENCE EXCHANGEintscience.weebly.com/uploads/1/3/3/6/13360003/supplement_2015.pdf · 110 THE HUMAN KIDNEYS A.6 EXCRETION New CROSS SECTION OF THE HUMAN

© Ron Mahabalsingh 2015

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Table of Contents SUMMARY OF EXPERIMENTS AND CRITERIA (CSEC Syllabus 2015) ........................................................ 4

FORMAT OF THE EXAMINATIONS ........................................................................................................... 8

SCHOOL BASED ASSESSMENT GUIDELINES ............................................................................................. 8

SBA SKILLS TO BE TESTED FOR CXC MODERATION ............................................................................. 8

IMPORTANT POINTS for Teachers ....................................................................................................... 9

SBA NOTEBOOKS for Students .......................................................................................................... 10

MODERATION OF THE SBA ................................................................................................................ 10

THE INVESTIGATIVE PROCESS ............................................................................................................... 11

Part A – The Proposal ........................................................................................................................ 11

Planning and Design (10 marks) .................................................................................................... 11

Part B – The Implementation ............................................................................................................ 13

Analysis and Interpretation (20 marks) ......................................................................................... 13

PLANNING AND DESIGN GUIDELINES .................................................................................................... 15

IDEA ................................................................................................................................................... 15

FORMAT ............................................................................................................................................ 15

STEPS FOR WRITING A P&D REPORT ................................................................................................. 16

MARK SCHEME FOR PLANNING AND DESIGN LABS .............................................................................. 18

GUIDELINES FOR DRAWING .................................................................................................................. 19

MARK SCHEME FOR DRAWING LABS .................................................................................................... 21

WRITING A METHOD THE EASY WAY .................................................................................................... 22

Introduction ...................................................................................................................................... 22

Demonstration .................................................................................................................................. 22

CONDITIONS NECESSARY FOR SEEDS TO GERMINATE .......................................................................... 27

Mark Scheme: Conditions Necessary for Seeds to Germinate...................................................... 28

CONSERVATION OF MOMENTUM ......................................................................................................... 30

Mark Scheme: Conservation of Momentum ................................................................................. 33

CYCLONIC STORMS ................................................................................................................................ 34

EFFECT OF EXERCISE ON PULSE RATE ................................................................................................... 37

Mark Scheme: Effect of exercise on pulse rate ............................................................................. 39

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ELECTRICAL CONDUCTORS AND INSULATORS ...................................................................................... 41

Mark scheme: Electrical Conductors and Insulators ..................................................................... 43

ENZYME ACTIVITY UNDER VARIOUS CONDITIONS ................................................................................ 44

Mark scheme: Enzyme activity under various conditions ............................................................. 45

HEAT OF NEUTRALIZATION ................................................................................................................... 46

Mark Scheme: Heat of Neutralization ........................................................................................... 47

LAW OF LEVERS ..................................................................................................................................... 48

Mark Scheme: Law of Levers ......................................................................................................... 50

PHYSICAL PROPERTIES OF WATER ........................................................................................................ 51

Mark Scheme: Physical Properties of Water ................................................................................. 53

PLANET PROPORTIONS .......................................................................................................................... 54

Mark Scheme: Planet Proportions ................................................................................................ 56

PREFERENTIAL RUSTING ........................................................................................................................ 57

Mark Scheme: Preferential Rusting............................................................................................... 59

RATE OF EVAPORATION ........................................................................................................................ 60

Mark Scheme: Rate of Evaporation............................................................................................... 62

REACTIONS OF VARIOUS METALS WITH HYDROCHLORIC ACID ............................................................ 63

Mark Scheme: Reactions of various metals with Hydrochloric Acid ............................................. 65

TESTING TWO UNKNOWN SAMPLES OF FOOD FOR VARIOUS NUTRIENTS .......................................... 66

Mark scheme: Testing two unknown samples of food for nutrients ............................................ 69

NEW DIAGRAMS .................................................................................................................................... 70

Diagram 1 Vertical Section of a Flower ............................................................................................. 70

Diagram 2 Major Bones in the Human Body ..................................................................................... 71

Diagram 3 Cross Section of the Skin .................................................................................................. 72


SUMMARY OF EXPERIMENTS AND CRITERIA (CSEC Syllabus 2015) CRITERIA SYLLABUS COVERAGE

PG TITLE ORR D MM AI PD UNIT TOPIC

95,96 LOOKING AT PLANT AND ANIMAL CELLS A.1 MATTER

36 DEMONSTRATION OF OSMOSIS A.1 MATTER

97-100 STORAGE ORGANS A.2 REPRODUCTION & GROWTH

64 GROWTH IN HUMANS A.2 REPRODUCTION & GROWTH

New VERTICAL SECTION OF THE HIBISICUS FLOWER A.2 REPRODUCTION & GROWTH

New CONDITIONS NECESSARY FOR SEED GERMINATION A.2 REPRODUCTION & GROWTH

33 TESTING A LEAF FOR THE PRESENCE OF STARCH A.3 FOOD & NUTRITION

39 TESTING VARIOUS FOODS FOR THE PRESENCE OF STARCH A.3 FOOD & NUTRITION

40 TESTING VARIOUS FOODS FOR THE PRESENCE OF PROTEIN A.3 FOOD & NUTRITION

42 TESTING VARIOUS FOODS FOR THE PRESENCE OF FATS AND OILS A.3 FOOD & NUTRITION

44 TESTING VARIOUS FOODS FOR THE PRESENCE OF REDUCING

SUGARS

A.3 FOOD & NUTRITION

53 HEAT RELEASED FROM A PEANUT A.3 FOOD & NUTRITION

101-

103 FOOD WEBS IN AQUATIC AND TERRESTRIAL ENVIRONMENTS


80 INVESTIGATE THE EFFECTS OF MOISTURE ON BREAD MOULD

GROWTH


New ENZYME ACTIVITY UNDER VARIOUS CONDITIONS A.3 FOOD & NUTRTION

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New TESTING TWO UNKNOWN SAMPLES OF FOOD FOR VARIOUS

NUTRIENTS

A.3 FOOD & NUTRTION

111 THE HUMAN HEART A.4 TRANSPORT SYSTEMS

New MAJOR BONES OF THE HUMAN SKELETON A.4 TRANSPORT SYSTEMS

New EFFECT OF EXERCISE ON PULSE RATE A.4 TRANSPORT SYSTEMS

46

CARBON DIOXIDE IN INHALED AND EXHALED AIR

A.5 RESPIRATION & AIR

POLLUTION

48

ANAEROBIC RESPIRATION IN YEAST


POLLUTION

76

EFFECTS OF SMOKING


POLLUTION

109

DIAGRAM OF THE LUNGS / ALVEOLI


POLLUTION

110 THE HUMAN KIDNEYS A.6 EXCRETION

New CROSS SECTION OF THE HUMAN SKIN A.6 EXCRETION

108

THE ENDOCRINE SYSTEM

A.7

SENSE ORGANS &

COORDINATION

107

A MOTOR NEURONE

A.7

SENSE ORGANS &

COORDINATION

61

REFLECTION USING A PLANE MIRROR

A.7

SENSE ORGANS &

COORDINATION

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51

CONDUCTION OF HEAT IN METALS

B.1 TEMPERATURE CONTROL &

VENTILATION

118

CERAMIC CUPS ARE BETTER FOR KEEPING TEA HOT LONGER


VENTILATION

New

RATE OF EVAPORATION


VENTILATION

New CONSERVATION OF MOMENTUM B.2 CONSERVATION OF ENERGY

84 OHM'S LAW - VOLTAGE, CURRENT AND RESISTANCE B.3 ELECTRICITY & LIGHTING

New ELECTRICAL CONDUCTORS AND INSULATORS B.3 ELECTRICITY & LIGHTING

69 HOOKE'S LAW B.4 MACHINES & MOVEMENT

114 PROTEIN FIBERS WOULD BE BETTER SUITED AS A LAB COAT THAN

NATURAL OR MANUFACTURED CELLULOSIC FIBERS

B.5 METALS & NON METALS

58 TESTING FOR COMMON IONS B.5 METALS & NON METALS

New PEFERENTIAL RUSTING B.5 METALS & NON METALS

New REACTION OF VARIOUS METALS WITH HYDROCHLORIC ACID B.5 METALS & NON METALS

116 DETERMINE IF BAKING POWDER IS A BETTER RAISING AGENT THAN

YEAST

B.6 ACIDS, BASES & MIXTURES

90 CLASSIFICATION OF HOUSEHOLD CHEMICALS BY pH B.6 ACIDS, BASES & MIXTURES

New HEAT OF NEUTRALIZATION B.6 ACIDS, BASES & MIXTURES

New

PLANET PROPORTIONS

C.1

THE UNIVERSE & OUR SOLAR

SYSTEM

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104,

105 CARBON, NITROGEN AND OXYGEN CYCLES

C.2

THE TERRESTRIAL

ENVIRONMENT

87

WATER DRAINAGE AND RETENTION IN DIFFERENT SOIL TYPES

C.2

THE TERRESTRIAL

ENVIRONMENT

New INVESTIGATE THE RELATIONSHIP BETWEEN WIND SPEED AND

SURFACE PRESSURE IN CYCLONIC STORMS

C.2

THE TERRESTRIAL

ENVIRONMENT

106

THE WATER CYCLE

C.3

WATER & THE AQUATIC

ENVIRONMENT

71

FINDING THE VOLUME OF ONE DROP OF WATER

C.3

WATER & THE AQUATIC

ENVIRONMENT

67

VOLUME OF AN IRREGULAR OBJECT

C.3

WATER & THE AQUATIC

ENVIRONMENT

New PHYSICAL PROPERTIES OF WATER: COMPARING FRESH WATER TO

SEA WATER

C.3 WATER & THE AQUATIC

ENVIRONMENT

56 MAGNETIC LINES OF FORCE C.5 FORCES

74 CENTRE OF GRAVITY C.5 FORCES

New LAW OF LEVERS C.5 FORCES

*Drawing labs with annotations / explanations can be useful for Analysis and Interpretation labs.

** Analysis and Interpretation OR Planning and Design labs can be reformulated (different variables / scenarios) for the Investigative Process for the CSEC 2015 syllabus

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FORMAT OF THE EXAMINATIONS

SUBJECT: INTEGRATED SCIENCE (SINGLE AWARD)

PROFICIENCY: GENERAL

EXAMINATIONS:

PAPER TIME DETAILS TOTAL PERCENTAGE (%)

01 1 hour 15 minutes 60 Multiple Choice Items 30

02 2 ½ hours Part A – Four Compulsory Structured Questions

Q1 – Practical type: Carries the MOST marks (25) and often includes Graphs

Q2 – Q4: 15marks each Part B – Two Compulsory Essay type questions (Q5 & Q6 : 15 marks each)

50

03/1 5 terms SBA 20

100

SCHOOL BASED ASSESSMENT GUIDELINES

SBA SKILLS TO BE TESTED FOR CXC MODERATION

SKILLS FORM 4

T 1 - 3

MARKS

FORM 5

T 4 & 5

MARKS

TOTAL

OBSERVATION / REPORTING / RECORDING (ORR) 1 10 1 10 20

DRAWING (D) 1 10 10

MANIPULATION AND MEASUREMENT (MM) 1 10 1 10 20

ANALYSIS AND INTERPRETATION (AI) 1 10 1* 20 30

PLANNING AND DESIGN (PD) 1 10 1* 10 20

TOTAL 5 50 4 50 100

*Investigative Project

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IMPORTANT POINTS for Teachers

The Investigative Project is to be executed in Form 5 (Suggested - Term 1)

Marks are to be submitted to CXC each year

The minimum number of labs over the 2 year period is eighteen (18)

Each skill must be assessed at least 2 times

o Suggested – Follow previous CXC guideline: (exception - 2 P&D in Yr 1)

SKILLS FORM 4 FORM 5

NO. OF LABS ASSESSED

NO. OF LABS ASSESSED

TOTAL NO. ASSESSED

OBSERVATION / REPORTING / RECORDING (ORR)

2 2 4

DRAWING (D) 2 2 4

MANIPULATION / MEASUREMENT (MM) 2 2 4

ANALYSIS & INTERPRETATION (AI) 2 2 4

PLANNING & DESIGN (PD) 2 - 2

TOTAL 10 8 18

A final mark can be determined by finding the averages of two or more labs assessed for

one skill

The practical selected must be executed and the report written within the class period

Books are to be collected at the end of the period

No more than two skills should be assessed for any one activity

The criteria tested should be clearly stated

Students must be aware of the mark schemes beforehand and have prior experience

using the various materials and apparatus

A minimum of 1 lab of a technological nature and 4 labs of an investigative nature must

be carried out

The percentage awarded to the SBA component of 20% has NOT changed although the

format of the written exams (Paper 02) has been altered slightly

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SBA NOTEBOOKS for Students The front of the notebook should carry the following information (Ink & Block Letters)

o Name

o School

o School Centre Number

o Form and Exam Year

o Teacher

Each lab report must have

o Page number(s)

o Date

The table of contents should have an asterisk (*) next to the labs being assessed by CXC

Above all, keep the SBA notebook in a presentable manner

MODERATION OF THE SBA The 2nd visit of the Moderator occurs in Term 2 of Form 5

5 candidates will be re-assessed by the moderator for various skills and the investigative

project

o The students are chosen in the same manner that the SBA books were sampled

previously

Candidates may need to demonstrate Manipulation and Measurement skills

Teachers assessments, for example the record of marks, should also be made available

to the Moderator

Teachers marks may be adjusted according to the Moderator’s marks and additional

candidates books may also be marked

The Moderator submits the following to the Local Registrar:

o Assessment Sheets

o Moderation of the SBA Sample and

o Moderation Reports

Copies of these documents must be retained by the school for a period of 3 months

after the release of exam results

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THE INVESTIGATIVE PROCESS

An Investigative Project has been added as a major part of the School Based Assessment (SBA). It

consists of two parts: The Proposal and The Implementation. The investigation is to be carried out in

Year 2, requires the students to carry out limited research and execute the planned experiment. The

skills assessed are Planning and Design for the Proposal component and Analysis and Interpretation

for the Implementation component.

Part A – The Proposal

Planning and Design (10 marks) Mark Scheme p 53 of the syllabus

Statement of the problem: This can be based on an observation or a problem

Hypothesis

o Testable

o Clear Concise Statement

Aim: Linked to the Hypothesis

Materials / Apparatus

Method (Present Tense)

o Precautions / Assumptions / Sources of Error

o Variables

Controlled

Manipulated

Responding

Expected Results OR Data Capture: Statement(s) of expected results to accept / reject

the hypothesis OR Tables that will be used to collect data on execution of the

experiment

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Part B – The Implementation

Analysis and Interpretation (20 marks) Mark Scheme p 54 of the syllabus

Introduction: Research into the observation or problem

Method (Past Tense)

Results

o Correct formulae and equations

o Accuracy of data

Discussion

o Explanation

o Interpretation

o Trends

Limitations

o Precautions / Assumptions / Sources of Error

Reflection

o Relevance

o Impact

o Justification for adjustments

o Communication of information (Expression)

o Conclusion

Stated

Related to Aim

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Exemplars of the investigative project are found in the CXC Syllabus (CXC 23/G/SYLL 15) pages 55 -

69

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PLANNING AND DESIGN GUIDELINES

IDEA

The idea behind the Planning and Design lab report is that YOU are writing a lab report that

ANOTHER person should be able to follow and execute.

For example, when giving a lost driver directions, it must follow logical steps that can be repeated to

the give the same end result.

*Note: The Investigative Project Planning and Design format is slightly different from the normal

Planning and Design.

FORMAT

AIM – Linked to the hypothesis. Similar to the Aim in a typical lab report.

HYPOTHESIS - A tentative assumption made in order to draw out and test its logical or

empirical consequences. (© 2015 Merriam-Webster, Incorporated)

APPARATUS – Materials, Instruments to be used.

METHOD – The procedure of the lab. The method is NUMBERED and written in PRESENT

tense.

RESULTS – Data capture. For example, tables that may be used to collect the Results.

Expected Results are also stated, that is, what would be the Responding variable(s).

DISCUSSION – How Results would be used to prove / falsify the Hypothesis.

Assumptions, Limitations and Sources of Error are also stated here.

CONCLUSION – Statement linked to the Hypothesis.

https://secure.merriam-webster.com/msdictionary/empirical

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STEPS FOR WRITING A P&D REPORT

Develop a Hypothesis based on observations / empirical data.

o The statement of Hypothesis must be clear, concise and testable.

o Example: Acetone is a better solvent for removing nail polish than alcohol.

Once the Hypothesis is established, start the lab report by writing the Aim.

o The Aim should state the intention of the experiment.

o Example: To investigate whether acetone is a better solvent for removing nail

polish than alcohol.

List all the apparatus that will be needed for the experiment.

o Remember, when listing the apparatus, keep in mind that a Control must be

used in the experiment.

o Be aware of the variables that will be controlled and the variable(s) that would

be responding.

o The Hypothesis or Aim should tell you what the Manipulated Variables are.

The Method should be written in concise, logical steps.

o The Method would be similar to experiments you have followed in lab manuals.

(A great example would be following a recipe in a cookbook)

What are we measuring? In other words, what are the Responding variable(s) in the

experiment? From this question, we should be able to develop various ways of

collecting the results. In most cases, a table would be appropriate.

o Example:

Solvent Average amount of nail polish removed

from surface (%)

Water (Control)

Acetone

Alcohol

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Note that the use of technology is also being encouraged, and, the capture of Results

could demonstrate this.

o Example:

Solvent Photo of Nail Polish Slide Before Photo of Nail Polish Slide After

Water

(Control)

Acetone

Alcohol

Next, state what the Expected Results should be.

o Example: The slide in which the highest percentage of nail polish is removed is

the best solvent.

The Discussion links the Expected Results to the Hypothesis. It states what we think will

happen and whether it proves or nullifies the hypothesis.

o In this section, the Precautions, Limitations and Sources of Error are included,

two in total.

The Conclusion is a summary statement that is linked to the Hypothesis.

o Example: If acetone is a better solvent for removing nail polish than alcohol,

then the hypothesis is true.

o This could also be said another way: If acetone is not a better solvent for

removing nail polish than alcohol, then the hypothesis is false.

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MARK SCHEME FOR PLANNING AND DESIGN LABS

CRITERIA TESTED: PLANNING AND DESIGN

MARKS

HYPOTHESIS (i) Clear, concise statement of hypothesis 1

(ii) Testable 1

DESIGN

Aim

(i) Clearly stated and relevant to hypothesis 1

Materials / Apparatus (ii) Apparatus to be used is adequate 1

Procedure

(iii) Logical sequence; Can be duplicated

Manipulated / Responding variable(s) stated

2

Results (iv) Suitable representation of results 1

Discussion (v) Use of results: How results used to prove / disprove the

hypothesis

1

(vi) Precautions / Sources of Error / Limitations 1

Conclusion (vii) Linked to Hypothesis 1

TOTAL 10

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GUIDELINES FOR DRAWING

You need 2 HB pencils, a sharpener, ruler and an eraser.

Draw on blank pages, sometimes found at the back of the SBA notebook.

ALL work must be done using a SHARP PENCIL. This includes drawing and labelling.

Draw THREE straight lines at the bottom left of the page, similar to lines in a notebook,

approximately ½ the width of the page. (see the example below)

o These lines are for writing in the

TITLE

SECTION and

MAGNIFICATION of your drawing.

Draw the object large enough so that most of the page is occupied, leaving room for

labelling.

o If there are few labels, the drawing should be aligned to the left of the page

with labels on the right only.

o If there are many labels, the drawing should be at the centre of the page with

labels on both sides of it.

Do NOT sketch when drawing a line. Draw CLEAN, CONTINUOUS lines from point A to

point B.

Shading or colouring is NOT permitted.

o Draw TWO lines side by side to represent thicker lines.

o Use stippling, cross-hatching or symbols to differentiate structures in the

drawing.

Labelling:

o Draw labelling lines using a ruler.

o Label lines should be, as much as possible, horizontal (or at least parallel to each

other) and spaced equally apart.

o Labels should be written in PENCIL and in BLOCK LETTERS.

o Do NOT cross labelling lines or use arrowheads.

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Write in the Title, Section and Magnification to complete the drawing.

o Magnification is calculated as follows:

𝑴𝒂𝒈𝒏𝒊𝒇𝒊𝒄𝒂𝒕𝒊𝒐𝒏 = 𝑺𝒊𝒛𝒆 𝒐𝒇𝒅𝒓𝒂𝒘𝒊𝒏𝒈

𝒐𝒃𝒋𝒆𝒄𝒕

*This value has to be multiplied by the magnification of lenses in a light

microscope if used.

EXAMPLE:

*Don’t forget to write in the Date, Page Number and Lab Number

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MARK SCHEME FOR DRAWING LABS

CRITERIA TESTED: DRAWING

MARKS

CLARITY (i) Large 1

(ii) Clear, single, continuous lines 1

(iii) Title 1

(iv) Two-Dimensional (No shading / colouring) 1

(v) Appropriate labelling and/or annotations

All present - 2

Some present - 1

None present - 0

2

ACCURACY (i) Proportion and Accuracy 2

(ii) Magnification 1

(iii) View correctly stated 1

LABEL LINES (i) No arrowheads 1

(ii) No crossing of label lines 1

(iii) Use of a ruler and pencil 1

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WRITING A METHOD THE EASY WAY

Introduction Most times, the Method can be written simply by changing the procedure into past tense. Of course,

this should be done during the lab session taking into account any changes to the procedure that

have taken place.

Keep in mind that this is not intended to be used as the only means to write a Method, but rather a

way of helping students who may be weaker in the area of English.

Demonstration

Method:

1. Using tweezers, place leaf in hot water for 5 minutes.

2. Remove leaf and place in a boiling tube containing about 5cm3 of ethanol.

3. Place this tube in a water bath for about 5 minutes or until the leaf is completely

decolourized.

Let’s try changing Sentence #1 into past tense:


Step 1: Eliminate the number of the sentence. Remember that the Method is written in paragraph

form.


Step 2: We don’t need to mention that a “tweezer” was used to place the leaf into hot water since this

was already mentioned in the Apparatus section of the lab report.

Using tweezers, place leaf in hot water for 5 minutes.

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Step 3: Look for the verb or “action word” in the statement and cross it out. It is usually the FIRST word.

Place leaf in hot water for 5 minutes.

Step 4: Start the sentence properly introducing the noun.

The leaf

Step 5: Ask yourself, what happened to the leaf? Now bring back the verb as past tense.

The leaf was placed

Step 6: Finish the rest of the statement simply by re-writing the original line after the noun “leaf”. Ask

yourself, where was the leaf placed?

The leaf was placed in hot water for 5 minutes.

Sentence #2:


Step 1: Eliminate the number of the sentence.


Step 2: There are two verbs in this sentence separated by “and”. They are “remove” and “place”. Cross

them out.

Remove leaf and place in a boiling tube containing about 5cm3 of ethanol.

Step 3: Start the sentence properly with the noun.

The leaf

24


Step 4: Replace the first verb in past tense. (What happened to the leaf?)

The leaf was removed

Step 5: Add the second verb in past tense joining the sentence with “and”.

The leaf was removed and placed

Step 6: Finish off the sentence by re-writing the original statement.

The leaf was replaced and placed in a boiling tube containing about 5cm3 of ethanol.

Sentence #3:

3. Place this tube in a water bath for about 5 minutes or until the leaf is completely decolourized.

Note that this is a much longer sentence but is just as simple as Sentence #1.

Step 1: Eliminate the number of the sentence.

3. Place this tube in a water bath for about 5 minutes or until the leaf is completely decolourized.

Step 2: Cross out the verb. Remember that the FIRST word is usually an action word.

Place this tube in a water bath for about 5 minutes or until the leaf is completely decolourized.

Step 3: Start the sentence properly with the noun.

This tube

Step 4: Replace the verb in past tense.

This tube was placed

25


Step 5: Finish the statement by re-writing the remainder of the sentence.

This tube was placed in a water bath for about 5 minutes or until the leaf was completely

decolourized.

Note that an exact time can be put rather than “or until the leaf was…”

These are just three of many examples. Try it on your own with any method from the manual. Let

your teacher look at them until you get the hang of it.

1. Clamp a metre rule vertically and suspend a spring from the clamp.

2. Attach an optical pin to the bottom end of the spring using plasticine.

3. Hang the weight holder on the spring and note the scale reading (Original Length).

26


27


CONDITIONS NECESSARY FOR SEEDS TO GERMINATE

Lab # _____ Date: ______________

Aim: To determine the conditions necessary for seeds to germinate.

Apparatus: The apparatus was set up as shown below:

Method:

1. Label five boiling tubes A, B, C, D and E respectively.

2. Place a small piece of cotton wool into tubes A, C and D.

3. Soak the cotton wool with water.

4. Place a few spatulas of Anhydrous Calcium Chloride into tube B and place a piece of dry

cotton wool on top of it.

5. Place 2 seeds into each tube.

6. Add boiled and cooled water to tube E and pour a thin layer of oil on top.

7. Cover tubes B, C and D with cotton wool and tube E with a rubber bung.

8. Place tubes A and E in an open space. (Not in direct sunlight. It can be left in the lab).

9. Place tube B in a space that is dry and will not come into contact with moisture.

10. Place tube C in a dark cupboard. (You can also wrap the tube with foil if you wish).

11. Place tube D into the refrigerator.

E D C A B

Red Bean

Seed

Anhydrous

Calcium

Chloride

Cotton

Wool

Oil Boiled and

Cooled

Water

28


12. After 1 week look for signs of germination and measure the average height of the shoot

(if present).

13. Record your results in a suitable table.

Results:

Tube Variable Manipulated Germination (Y/N) Avg. height of shoot (cm)

A Control

B Water

C Light

D Temperature

E Air

Discussion:

1. Which tube(s) showed the greatest growth? What were the conditions absent?

2. Which tube(s) showed little or no growth? What were the conditions absent?

3. Based on your answers for 1 and 2, what are the conditions necessary for seeds to

germinate?

4. Why was the water boiled and cooled in tube E?

5. What was the purpose of using the oil in tube E?

6. Why was the temperature lowered in tube D rather than raised?

7. State TWO precautions / sources of error OR limitations.

Conclusion: The conditions necessary for germination to occur are

Mark Scheme: Conditions Necessary for Seeds to Germinate

CRITERIA TESTED: OBSERVATION, RECORDING AND REPORTING

ACCURACY OF RECORDING OBSERVATIONS IN A TABLE MARKS

(i) Germination present or absent in each tube (5 x 1) 5

(ii) Record of average height in each tube (5 x 1) 5

10

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CRITERIA TESTED: ANALYSIS AND INTERPRETATION

SUMMARISES DATA MARKS

(i) Conditions absent in tube(s) with greatest growth

All conditions - 2

Some conditions - 1

None - 0

2

(ii) Conditions absent in tube(s) with least growth

All conditions - 2

Some conditions - 1

None - 0

2

(iii) States the conditions needed for seeds to germinate 3

EVALUATES DATA

(iv) Suggests why the temperature was lowered and not raised 1

(v) States two precautions / sources of error / limitations 2

10

CXC SYLLABUS COVERAGE: REPRODUCTION AND GROWTH

30


CONSERVATION OF MOMENTUM

Lab # _____ Date: ______________

Aim: To demonstrate conservation of momentum for inelastic collisions.

Apparatus: 2 trolley cars (of equal weights)

Trolley car masses

Ticker timer with power supply

Ticker timer tape

Runway

Wooden block

Scotch or Cellophane tape

Scale balance

Plasticine or Velcro

Ruler

Method:

1. Label each trolley car A or B respectively.

2. Record the weight of each trolley (if not known).

3. Set up the apparatus as shown below:

4. Turn on the ticker timer giving Trolley A a slight push.

Trolley A Trolley B

Plasticine

Ticker tape

Ticker Timer

Friction-

compensated

runway

Wooden Block

31


5. Turn off the ticker timer when both trolleys are at the end of the runway.

6. Measure the length of the tape used before collision and after collision.

7. Determine the initial and final velocity, 𝑢 =𝑑

𝑡,from the ticker tape. (Each space is

counted as 1/50th of a second – therefore 50 spaces take 1 second).

8. Calculate the momentum before and after collision. (𝑝 = 𝑚𝑣)

9. Repeat the experiment using different masses on the trolleys.

(Check out http://www.schoolphysics.co.uk/age11-14/Mechanics/Motion/text/Ticker_timer_and_speed/index.html for more info on the ticker

timer)

Results:

Table 1 showing time taken, distance and velocity of the trolleys before and after collision

Time taken (s)

Distance (cm) Velocity (cm/s)

# No. of spaces No. of spaces / 50

Length of Tape

Distance / Time taken

1

Trolley A

Trolley A + B

2

Trolley A

Trolley A + B

3

Trolley A

Trolley A + B

4

Trolley A

Trolley A + B

http://www.schoolphysics.co.uk/age11-14/Mechanics/Motion/text/Ticker_timer_and_speed/index.html

32


Table 2 showing the masses of trolleys, velocity and momentum before and after collision

Mass of Trolley A

(ma)

Mass of Trolley B

(mb)

Before collision After collision

u

Initial total momentum,

maua

v

Final total momentum, (ma + mb)v

1 m

m

2 m

2m

3 2m

m

4 2m

2m

Discussion:

1. Calculate the Initial total momentum and the Final total momentum for each pair of

masses.

2. What can you deduce about the total momentum before collision and the total

momentum after collision?

3. Were there any other factors that may have influenced the outcome of the experiment?

Explain your answer.

4. Define the term “Conservation of momentum” based on the experiment.

Conclusion: Conservation of momentum was demonstrated for inelastic collisions.


Mark Scheme: Conservation of Momentum

CRITERIA TESTED: MANIPULATION AND MEASUREMENT

USE OF BASIC LABORATORY EQUIPMENT MARKS

(i) Set up of ticker timer tape to Trolley A 1

(ii) Set Trolley B in a stationary position 1

(iii) Attach plasticine to both Trolleys 1

(iv) Use of the ticker timer (start, push, stop) 3

(v) Makes accurate reading of ticker timer tape (velocity)

Reads number of spaces before contact

Reads number of spaces after contact

Measures distance before contact

Measures distance after contact

4

10

CXC SYLLABUS COVERAGE: CONSERVATION OF ENERGY

34


CYCLONIC STORMS

Lab # _____ Date: ______________

Aim: To investigate the relationship between wind speed and surface pressure in cyclonic storms

Apparatus: Data of storms (2013) acquired from http://www.nhc.noaa.gov/

Saffir-Simpson Scale of Hurricane Intensity

Method:

1. Closely examine the data of five storms in 2013 from the Caribbean Sea.

2. Draw a graph of Wind Speed (y-axis) versus Surface Pressure (x-axis) for each storm. (see

sample graph for scale)

3. Draw the straight line of best fit.

Results:

Table 1 showing the wind speed and surface pressure of five storms

Storm Wind Speed (kph) Surface Pressure (mb)

Barry (June 16 – June 20) 37 1009

46 1008

46 1009

74 1005

56 1007

Chantal (July 7 – July 10) 65 1011

83 1007

102 1003

93 1005

74 1010

Dorian (July 22 – Aug 4) 46 1009

83 1004

93 1002

65 1013

56 1012

Gabrielle (Sept 4 – Sept 13) 56 1010

37 1010

102 1003

46 1008

56 1007

http://www.nhc.noaa.gov/

35


Storm Wind Speed (kph) Surface Pressure (mb)

Karen (Oct 3 – Oct 5) 83 1006

102 1001

102 998

74 1004

65 1008

Table 2 showing the Saffir-Simpson scale of hurricane intensity

Type Category Wind Speed (kph)

Tropical Depression TD < 64

Tropical Storm TS 64 – 118

Hurricane 1 119 – 153




Hurricane 5 > 250

Discussion:

1. Based on your graph, what is the relationship between Wind Speed and Surface

Pressure?

2. Suggest a reason for the relationship between wind speed and surface pressure.

3. Using table 2, describe the type and category of each storm based on their greatest

wind speed.

4. Suggest a 6 month period of the year when cyclonic storms most likely to occur?

Conclusion: As wind speed ________________, surface pressure ________________.

Check out http://www.weatherwizkids.com/weather-hurricane.htm for more information on Hurricanes

http://www.weatherwizkids.com/weather-hurricane.htm

36


Sample Graph:

CRITERIA TESTED: ORGANISATION, RECORDING AND REPORTING

GRAPHS MARKS

(i) Axes labelled 2

(ii) Appropriate scales used 2

(iii) Accurate plotting for each storm (1 x 5) 5

(iv) Straight line of best fit 1

10



(i) States the relationship between Wind Speed and Surface Pressure 1

(ii) Suggests a reason for the relationship between Wind Speed and Surface

Pressure

2

(iii) Categorizes each storm according to the Saffir-Simpson Scale 5

(iv) Suggests a 6 month period storms are most likely to occur (Acc – 2; Fair

– 1)

2

10

CXC SYLLABUS COVERAGE: THE TERRESTRIAL ENVIRONMENT

37


EFFECT OF EXERCISE ON PULSE RATE

Lab # _____ Date: ______________

Aim: To determine the effect of exercise on pulse rate.

Apparatus: 1 stopwatch

Method:

1. Remain seated (or lie down) for the first pulse reading.

2. Place two fingers on the inner wrist of the left arm and locate the radial pulse.

3. Count the number of beats for 15 seconds.

4. Record the value in the results table 1.

5. Locate the carotid pulse (on either side of your neck) and count the number of beats for

15 seconds.

6. Repeat the pulse reading two more times.

7. Now, stand and measure the radial pulse reading for 15 seconds.

8. Again, record your results in table 2 and repeat two more times.

9. Do some form of mild exercise for about 1 minute.

10. Measure the radial pulse rate and record your results.

11. Repeat mild exercise and pulse reading two more times.

12. Record your results.

13. Rest for a period of 5 minutes, and while seated, measure the radial pulse reading a

total of three times.

14. Record your results.

15. Calculate the beats per minute (bpm) by multiplying the pulse readings by 4.

38


Results:

Table 1 showing Radial and Carotid Pulse Rates at rest.

Radial Pulse Rate (rest) Carotid Pulse Rate (rest)

Beats in 15 seconds

Beats per minute Beats in 15 seconds

Beats per minute

1

2

3

AVG

Table 2 showing Radial Pulse Rates before, during and after exercise.

Pulse Rate (before) Pulse Rate (during) Pulse Rate (after)

Beats in 15 seconds

Beats per minute

Beats in 15 seconds

Beats per minute

Beats in 15 seconds

Beats per minute

1

2

3

AVG

Discussion:

1. The normal pulse rate for a person at rest is between 60 – 100 bpm. How does your

pulse rate compare to this?

2. Was there any difference between the Radial Pulse and Carotid Pulse at rest? Do you

think there should be? Explain your answer.

3. Was there a difference in pulse rate at rest and before exercise? If so, what do you think

may be the reason?

4. What happened to the pulse rate during exercise and after exercise? Can you explain

the changes?

5. Do you think an athlete’s pulse rate will be higher or lower than your value? Explain.

6. Besides exercise, what other factor do you think will affect pulse rate?

Conclusion: The pulse rate ______________ with exercise.

39


(See Pulse Points in the Human Body in the Drawing Appendix)

Mark Scheme: Effect of exercise on pulse rate


ORGANISATION AND CONCISENESS MARKS

(i) Logical sequence of report 2

(ii) Sections named 2

(iii) Proper use of tables (correct values in correct cells before

calculations) ( 1 x 5)

5

(iv) Correct use of terminology and expressions (bpm, pulse rate etc.) 1

10



(i) Calculates the average bpm for each category (1 x 5) 5

(ii) Gives a suitable explanation for any difference between Radial and Carotid pulse

1

(iii) Gives a suitable explanation for any difference between rest and before exercise

1

(iv) Explains the changes between pulse rate during and after exercise 2

(v) Predicts whether an athlete’s pulse rate will be higher or lower than their value

1

10

CXC SYLLABUS COVERAGE: TRANSPORT SYSTEMS

40


Diagram 19: Pulse Points in the Human Body

41


ELECTRICAL CONDUCTORS AND INSULATORS

Lab # _____ Date: ______________

Aim: To determine whether a material is an electrical conductor or insulator

Apparatus: The apparatus was set up as shown below.

Method:

1. Attach opposite ends of the optical pin to the crocodile clips to complete the circuit.

(Ensure that the crocodile clips are not touching each other)

2. Turn on the switch.

3. Observe and record whether the bulb lights or not.

4. Repeat the procedure for each material to be tested.

Results:

Observation Conclusion

Material Light bulb ON or OFF Conductor or Insulator

Optical pin

Cork

Paper

Staple

Battery

Switch Connecting wires

Light bulb

Crocodile clips

42


Material Light bulb ON or OFF Conductor or Insulator

Matches

Styrofoam

Wooden splint

Paper clip

Glass rod

Foil

Steel nail

Thumb tack

Candle

Galvanize wire

Aluminium rod

Cardboard

Thread

Copper wire

Rubber band

Twine

Steel wool

J-Cloth

Plastic straw

Discussion:

1. From your experiment, what is meant by a material that is a conductor and a material

that is an insulator?

2. Would you say that all conductors in this experiment were metals? If so, what is the

property of metals that would make them conductors?

3. Were there any insulators that were metals? What property of non-metals makes them

insulators?

4. Why should you ensure that the crocodile clips do not touch each other in this

experiment?

5. If a metal does not show up as a conductor in this experiment, what is one possible

explanation?

6. What do you think would be a use of insulators in the home?

43


Conclusion: Materials were determined as either conductors or insulators in this experiment.

Mark scheme: Electrical Conductors and Insulators


SUMMARISES DATA – Makes Predictions / Inferences

MARKS

i. Definition of Conductor and Insulator 2

ii. States if conductors were metals or not 1

iii. States a property of metals related to electrical conductivity 1

iv. States if insulators were metals or not 1

v. States a property of non-metals related to electrical conductivity 1

vi. Determines why crocodile clips should not touch 1

vii. Determines a suitable use on an insulator in the home 1

TOTAL 8

SYLLABUS COVERAGE: ELECTRICITY AND LIGHTING

44


ENZYME ACTIVITY UNDER VARIOUS CONDITIONS

Lab # _____ Date: ______________

Aim: To investigate the activity of enzymes under various conditions

Apparatus: 6 test tubes

Hot plate

Water bath (or 500mL beaker)

Dilute Hydrochloric Acid (HCl)

Dilute Sodium Hydroxide (NaOH)

Iodine solution

Distilled water

Starch solution

Diastase

Pepsin

Benedict’s solution

Testing tile

Method:

1. Label 6 test tubes A to F respectively.

2. Pour 2mL of starch solution into each tube.

3. Add 2mL of water to tube A.

4. Add 2mL of Diastase to tube B.

5. Add 2mL of boiled Diastase to tube C.

6. Add 2mL of Diastase and 3 drops of HCl to tube D.

7. Add 2mL of Diastase and 3 drops of NaOH to tube E.

8. Add 2mL of Pepsin to tube F.

9. Shake the contents of each tube.

10. Pour a sample of each tube onto a testing tile.

11. Test each sample for the presence of starch.

12. Test the remainder of the sample in the tube(s) for reducing sugars where starch was

absent.

45


Results:

Observation

Tube Test for Starch Test for Reducing sugars

A

B

C

D

E

F

Discussion:

1. Explain the inferences in tubes A, B, C, D and E.

2. Why was tube A included in this experiment?

3. Why was tube F included in this experiment?

4. Based on your results, suggest an optimum pH for Diastase.

Conclusion: The action of enzymes under various conditions was investigated.

Mark scheme: Enzyme activity under various conditions

CRITERIA TESTED: ANALYSIS & INTERPRETATION

SUMMARISES DATA

Makes Predictions / Inferences MARKS

(i) Explains the inference in tubes A, C, D, E and F (5 x 1) 5

(ii) Explains the inference in tube B (for both Iodine and Benedict’s test) 2

(iii) States the purpose of including tube A 1

(iv) States the purpose of including tube F 1

(v) Suggests an optimum pH for Diastase 1

TOTAL 10

SYLLABUS COVERAGE: FOOD & NUTRITION

46


HEAT OF NEUTRALIZATION

Lab # _____ Date: ______________

Aim: To determine the volume of acid required to completely neutralize an alkali by temperature.

Apparatus: 1M Hydrochloric Acid (HCl)

1M Sodium Hydroxide (NaOH)

Styrofoam cup

Thermometer

Stirring rod

2 25cm3 measuring cylinders

2 50cm3 beakers

Acid-Base Indicator

Method:

1. Measure 25cm3 of NaOH and pour into a Styrofoam cup.

2. Add 2-3 drops of an acid-base indicator.

3. Note the colour of the NaOH solution.

4. Stir the NaOH then record the constant temperature reached.

5. Add 5cm3 of HCl to the cup and stir.

6. Record the highest temperature reached and note the colour of the acid-base solution.

7. Add an additional 5cm3 of HCl and stir.

8. Record the highest temperature reached and note the colour of the acid-base solution.

9. Repeat the procedure 5 more times until a total of 35cm3 of acid has been added.

Results:

Volume of HCl added (cm3) Temperature (0C) Colour of Solution

0

5

10

15

20

25

30

35

47


Discussion:

1. Write the word equation for the reaction between an acid and a base.

2. Draw a graph of Volume of HCl added (x-axis) versus Temperature ( y-axis) and

a. Determine the maximum temperature attained.

b. What does this value mean?

3. Explain the shape of your graph.

4. Is the reaction endothermic or exothermic? Explain your answer.

5. Why was a Styrofoam cup used instead of glassware such as a beaker or conical flask?

6. Do you think that this was an accurate method to determine the end-point of the

reaction? If not, why?

7. How could you improve the accuracy and reliability of this experiment?

8. Does the colour change help us know if the reaction has been completed? Explain your

answer.

Conclusion: The volume of acid required to completely neutralize an alkali by temperature was

__________ cm3.

Mark Scheme: Heat of Neutralization

MANIPULATION & MEASUREMENT

MARKS

(i) Proper use of a measuring cylinder

Placing flat on bench and reading at eye level

Accurately reading below the meniscus

Careful transfer of solution into Styrofoam cup

1 1 1

(ii) Use of the thermometer

Full immersion of bulb in solution

Avoiding hitting bulb on sides of container

Allowing acclimatization before reading

Accurately reading at eye level

1 1 1 1

(iii) Holding the Styrofoam cup during use of the thermometer 1

(iv) Removing the thermometer after each reading 1

(v) Neat and organized workspace 1

TOTAL 10

SYLLABUS COVERAGE: ACIDS, BASES & MIXTURES

48


LAW OF LEVERS

Lab # _____ Date: ______________

Aim: To verify the principle of moments - when an object is in equilibrium, the sum of anticlockwise

moments about any point equals the sum of clockwise moments about the same point.

Apparatus: Metre rule with hole at the 50cm mark

Retort stand

Plasticine

Cork with nail (or optical pin)

2 x 200g, 150g and 100g masses (with string)

Method: The apparatus was set up as shown below

m1

d1 d2

m2 ANTI-CLOCKWISE

MOMENT

CLOCKWISE

MOMENT

49


1. Place the 200g mass (m1) at 15cm (d1) away from the fulcrum. (This mass represents the

load)

2. Place another 200g mass (m2) on the other side of the fulcrum and adjust the distance

(d2) until the ruler is in equilibrium. (This mass represents the effort)

3. Record the distance, d2.

4. Replace m2 with a 150g mass then a 100g mass, each time recording d2 when the ruler is

in equilibrium.

5. Adjust d1 to 10cm and repeat the procedure for m2 with 200g, 150g and 100g.

6. Adjust d1 to 5cm and repeat the procedure for m2 with 200g, 150g and 100g.

Results:

Anti – clockwise moment Clockwise moment

m1 d1 m1 x d1 m2 d2 m2 x d2 Does m1 x d1 = m2 x

d2? (margin of error

100)

Load (g) Distance from fulcrum (cm)

Effort (g) Distance from fulcrum (cm)

200 15 200

200 15 150

200 15 100

200 10 200

200 10 150

200 10 100

200 5 200

200 5 150

200 5 100

Discussion:

1. Based on your results, determine what happens to d2 each time the Effort is decreased?

2. Explain why the lever (metre rule) can be balanced even though the Load (m1) and the

Effort (m2) may be different.

3. Does m1 x d1 = m2 x d2? What does it say about the Anti – clockwise and the Clockwise

moments at equilibrium?

50


4. A boy and girl are sitting on opposite ends of a see-saw. The boy weighs 40kg and is

sitting 3m away from the centre. The girl weighs 30kg. At would distance would the girl

have to sit for the see-saw to balance?

Conclusion: The principle of moments was verified – when the ruler was ________________, the

anti-clockwise moment about the fulcrum was _____________ to the clockwise

moments about the same point.

Mark Scheme: Law of Levers

MANIPULATION & MEASUREMENT

MARKS

(i) Assembly of apparatus 1

(ii) Balancing of ruler using plasticine 1

(iii) Keeping the ruler balanced when adding mass m1 1

(iv) Placing m1 at the correct distance away from the fulcrum 1

(v) Keeping ruler horizontal when adding mass m2 1

(vi) Accurately reading distance d2 at equilibrium 1

(vii) Removing m2 while supporting the ruler 1

(viii) Adjusting m1 to the correct distance for next measurement 1

TOTAL 8

CXC SYLLABUS COVERAGE: MACHINES & MOVEMENT

51


PHYSICAL PROPERTIES OF WATER

Lab # _____ Date: ______________

Aim: To compare the freezing, melting and boiling points of fresh water and sea water.

Apparatus: Hot plate

2 x 250mL beakers

2 x 50mL measuring cylinders

Electric chopper / tools to crush ice cubes

Retort stand

2 boiling tubes

Thermometer

Stirring rod

2 Ice trays

Approximately 1000mL distilled water and sea water

Method:

Part 1 – Fresh Water

1. Place about 100mL of crushed ice made from distilled water into a 250mL beaker.

2. Add 50mL of distilled water to the beaker and place the ice bath on the hot plate (OFF).

3. Put about 5mL of crushed ice into a boiling tube.

4. Clamp tube to the retort stand and lower into ice bath.

5. Place thermometer into the tube.

6. Record the initial temperature.

7. Stir the contents of the water bath and take the temperature every minute for two

minutes.

8. Turn the hot plate on high and continue taking temperature readings every minute for a

total of 30 minutes.

9. Record the readings in a suitable table.

52


Part 2 – Sea Water

1. Create an ice bath made from sea water following the procedure described in Part 1

(Steps 1 & 2)

2. Repeat the procedure described in Part 1 (Steps 3 – 9).

Results:

Temperature (0C)

Time (minutes) Fresh Water Sea Water

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

53


Discussion:

1. Plot a graph of Temperature (y-axis) versus Time (x-axis) for Fresh Water and Sea Water.

2. From your graph, deduce the freezing, melting and boiling points of fresh water. Use a

table to represent your findings.

Fresh Water Sea Water

Boiling Point (oC)

Melting Point (oC)

Freezing Point (oC)

3. From your graph, deduce the freezing, melting and boiling points of sea water.

4. Explain any differences between the values for fresh water and sea water.

5. Using the graph, describe how the temperature of the water changed over time. (Relate

to Heat Energy)

Conclusion: The freezing, melting and boiling points of fresh water and sea water were compared.

Check out http://www.ozh2o.com/h2phys.html for more information on the Properties of Water

Mark Scheme: Physical Properties of Water


MARKS

(i) Using a beaker for rough measurement 1

(ii) Accurate measurement using a measuring cylinder

Reading the meniscus

Reading at eye level

2

(iii) Careful crushing of ice cubes 1

(iv) Clamping / positioning of boiling tube 2

(v) Careful use of the hot plate 1

(vi) Use of the thermometer

Reading at eye level

Keeping bulb immersed

Accurate interpretation of scale

3

10

CXC SYLLABUS COVERAGE: WATER AND THE AQUATIC ENVIRONMENT

http://www.ozh2o.com/h2phys.html

54


PLANET PROPORTIONS

(Recommended by Stacy DeVeau, Arizona NASA Educator Resource Center, Embry-Riddle Aeronautical University)

Lab # _____ Date: ______________

Aim: To understand the sizes of planets when compared to one another using models.

Apparatus: 1lb Modelling Clay (Plasticine or Play Doh)

1 utility knife

1 30cm ruler

9 sheets of paper

1 marker

Method:

1. Label each sheet of paper with the name of one planet and dwarf planet.

2. Place the labelled sheets in order of closest to furthest from the Sun.

3. Roll the modelling clay into a big ball and then into a hot dog shape.

4. Cut the modelling clay into 10 equal parts.

5. Combine 6 parts by rolling into a ball and place on Jupiter.

6. Combine 3 parts, roll and place on Saturn.

7. Cut the remaining part into 10 equal parts.

8. Combine 5 parts with Saturn, 2 parts to make Neptune and 2 parts on Uranus.


10. Combine 3 parts with Saturn.


12. Put 2 parts on Earth, 2 parts on Venus and combine 4 parts with Uranus.

13. Combine the remaining 2 parts and cut into 10 equal parts.

14. Put 1 part on Mars, combine 4 parts with Neptune and take 4 parts and combine with

Uranus.


16. Put 7 parts on Mercury and combine 2 parts with Uranus.


55


18. Combine 9 parts with Uranus and put 1 part on Pluto.

Results:

Take a photograph of the planets in order of closest to the Sun to furthest.

Cut each planet in half and measure its diameter and record in the table below:

Planet / Dwarf Planet Diameter (cm)

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

Pluto

(Check out the video on “The Science Experiment” facebook page)

Discussion:

1. Based on your results which planet would now be considered as a dwarf planet?

Why?

2. Which was the largest planet?

3. What was the size of Earth compared to the eight others?

4. Which planet do you think would have the largest gravitational pull? Why?

5. Which planet do you think would have the greatest number of moons? Why?

6. Why do you think that Jupiter and Saturn are called Giant Gas planets?

7. State any TWO precautions, limitations OR sources of error that should be taken

in this experiment.

Conclusion: The relative sizes of the planets and dwarf planet were compared using models.

56


Check out http://intscience.weebly.com/downloads.html “Planet Proportions” for a video of the completed

experiment.

Also visit “cool websites” for links to NASA and other Solar System videos

Mark Scheme: Planet Proportions



(i) Deduces which planet would be considered Dwarf 2

(ii) States with reason which planet has the largest gravitational pull 2

(iii) States with reason which planet would have the greatest number of

moons

2

(iv) States why Jupiter and Saturn are called Giant Gas Planets 2

(v) States TWO precautions / limitations / sources of error 2

10

CXC SYLLABUS COVERAGE: THE UNIVERSE AND OUR SOLAR SYSTEM

http://intscience.weebly.com/downloads.html

57


PREFERENTIAL RUSTING

Lab # _____ Date: ______________

Aim: To determine which metal, Aluminium or Copper, will prevent Iron from rusting.

Apparatus: 5 boiling tubes

1 25mL measuring cylinder

150mL of salt water solution (about 25%)

3 iron nails

Aluminium foil

Copper wire

The apparatus was set up as shown below:

Method:

1. Label the five boiling tubes A, B, C, D and E respectively.

2. Place 25mL of salt water solution into each boiling tube.

3. Wrap a thin strip of aluminium foil around one nail and copper wire around another.

4. Place the plain nail into the tube labelled A.

5. Place a piece of rolled aluminium foil (preferably same size and shape of the nail) into

tube B.

6. Place a piece of copper wire into tube C.

A B C D E

58


7. Place the nail with aluminium foil into the tube labelled D.

8. Place the nail with the copper wire into the tube labelled E.

9. Observe the rates of rusting for about 40 minutes or until significant results are visible.

(Note: Observations made must compare rates of rusting among tubes)

Results:

Tube Observation

A Control

B Aluminium

C Copper

D Aluminium &

Iron

E Copper & Iron

Discussion:

1. What do you understand by the term “rusting”?

2. Why was the control tube included in this experiment?

3. Why do you think tubes B and C were included in this experiment?

4. Which tube did the iron nail show the least amount and greatest amount of rusting?

5. Explain the observations in tubes D and E.

6. What do you think is the significance of the experiment?

7. What do you think the term “preferential rusting” means?

8. Name one precaution OR source of error in this experiment.

Conclusion: The metal that can be used to prevent rusting in Iron is _______________.

59


Mark Scheme: Preferential Rusting


SUMMARISES & EVALUATES DATA MARKS

(i) Indicates why the control tube was included 1

(ii) Infers as to why tubes B and C were included 2

(iii) Explanation for the observation in tube D 2

(iv) Explanation for the observation in tube E 2

(v) Based on the results, gives the significance of the experiment 1

(vi) States what “preferential rusting” means 1

(vii) States one precaution or source of error 1

10


SIGNIFICANT CHANGES RECORDED MARKS

(i) Observations for Tube A compared to others 2

(ii) Observations for Tube B compared to others 2

(iii) Observations for Tube C compared to others 2

(iv) Observations for Tube D compared to others 2

(v) Observations for Tube E compared to others 2

10

CXC SYLLABUS COVERAGE: METALS AND NON - METALS

60


RATE OF EVAPORATION

Lab # _____ Date: ______________

Aim: To determine how temperature, wind and humidity affect the rate of evaporation.

Apparatus: 500mL beaker

50mL measuring cylinder

1 hand towel / handkerchief

2 clothes pins

Clothes line

Internet access

Method:

1. Fold and place hand towel into the 500mL beaker.

2. Measure 50mL of water and pour gradually over the hand towel until it is damp. (This is

the point where the towel is wet but does not drip)

3. Make a note of the volume of water used to dampen the hand towel.

4. Hang the hand towel on the clothes line.

5. Check the hand towel every 10 minutes and record the time taken for it to become dry.

6. During drying time of the hand towel, visit www.weather.com and type in country (and

area).

7. Record the Temperature, Humidity, Wind Speed and Barometric Pressure.

8. Repeat the procedure every day, at the same time, for about 2 weeks.

*Note: Time and place of the experiment must not change. Record Wind Speed as either Low (<

5mph), Moderate (bet 6 – 14mph) or High (> 14mph).

http://www.weather.com/

61


Results:

Day Temperature (oC)

Wind Speed (Low,

Moderate, High)

Humidity (%) Barometric Pressure

(mb)

Time taken to dry (min)

1

2

3

4

5

6

7

8

9

10

(add rows if necessary)

Discussion:

1. How does Temperature affect the rate of evaporation?

2. How does Wind Speed affect the rate of evaporation?

3. How does Humidity affect the rate of evaporation?

4. Do you think Barometric Pressure also has an effect on the rate of Evaporation? Explain

your answer.

5. Do you think that the above variables, excluding Barometric Pressure, are related in any

way or act independently on the rate of evaporation? Explain your answer.

(Helpful Hint: When two variables are constant, and the other changes, is the rate of

evaporation affected?)

Conclusion: As temperature _______________, wind speed _______________ and humidity

_______________, the Rate of Evaporation _______________.

Check out http://van.physics.illinois.edu/qa/listing.php?id=1440 for more information on the Rate of Evaporation.

http://van.physics.illinois.edu/qa/listing.php?id=1440

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Mark Scheme: Rate of Evaporation


MAKES ACCURATE RECORDINGS AND OBSERVATIONS MARKS

(i) Determines the point where the towel is damp 1

(ii) Determines the volume required to repeat proper dampening 1

(ii) Uses the internet to collect data (1 x 4) 4

(iii) Determines the point where the towel is dry 1

TABLE (NUMERICAL AND NON NUMERICAL)

(iv) Attention to kinds of data:

Units – 2 to 0

Non – unit - 1

3

10

CXC SYLLABUS COVERAGE: TEMPERATURE CONTROL AND VENTILATION

63


REACTIONS OF VARIOUS METALS WITH HYDROCHLORIC ACID

Lab # _____ Date: ______________

Aim: To investigate the reactions of various metals with Hydrochloric Acid.

Apparatus: 1 cm Magnesium ribbon

2 – 3 pieces of Zinc

2 – 3 pieces of Chromel wire

2 Iron staples

1 cm Aluminium wire

1 cm Tin foil

Scissors

7 test tubes

Test tube rack

Concentrated Hydrochloric Acid (conc. HCl)

5mL measuring cylinder / dropper

Forceps

Method:

1. Label each test tube with the element symbol that will be added to it. (E.g. Mg for

Magnesium ribbon).

2. Pour about 1mL of conc. HCl to each tube.

3. Add small amounts of each metal, one at a time, to the appropriate tube.

4. Observe the reaction of each tube and rate of effervescence.

5. Record your observations in the table below and give a score of 4 to the metal that had

the greatest reaction and a score of 0 for the metals with the lowest / no reaction. (row

reads “Reactivity”)

6. Let the tubes stand for 20 minutes and again record your observations.

7. Rank the order of reactivity for each metal from 1st (most reactive) to 7th (least reactive).

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Results:

Metal Mg Zn Cu NiCr Fe Sn Al

Immediate Observations

Observations after 20 minutes

Reactivity (0 – 4)

Order of Reactivity (1st – 7th)

Discussion:

1. Based on your results, create a table of the metals in an activity series, most reactive at

the top and least reactive at the bottom.

2. What was the gas given off when the most reactive metal was added to the conc. HCl?

3. Besides bubbles being given off, what was another observation about the tube with the

most reactive metal?

4. What type of precautions would you take in an experiment such as this? State any TWO.

5. What metal would you chose from the list above to build a car. Why?

Conclusion: The reactions of various metals with Hydrochloric Acid were investigated.

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Mark Scheme: Reactions of various metals with Hydrochloric Acid


USE OF BASIC LABORATORY EQUIPMENT MARKS

(i) Careful handling of conc. HCl reagent bottle (pour / replace stopper) 2

(ii) Measuring and transferring about 1mL HCl to each tube 2

(iii) Preparation of metals samples 2

(iv) Careful addition of metal to each tube using forceps 2

(v) Observation of tubes with care and due attention 1

(vi) Organisation of workplace to minimize accidents 1

10

CRITERIA TESTED: ORGANISATION, RECORDING AND REPORTING

SIGNIFICANT CHANGES RECORDED MARKS

(i) Correctly rates reactivity for each metal (0 – 4)

6 – 7 metals ranked correctly = 4



1 metal ranked correctly = 1

4

ATTENTION TO DETAILS OF DATA

(ii) Immediate observations for each tube (effervescence and heat)

All accurate = 3

Most accurate = 2

Some accurate = 1

None accurate = 0

3

(iii) Observations after 20 minutes

All accurate = 3

Most accurate = 2

Some accurate = 1

None accurate = 0

3

10

CXC SYLLABUS COVERAGE: METALS AND NON - METALS

[1]. Holtzclaw, HF, Robinson, WR and Odom, JD: General Chemistry with Qualitative Analysis, 9th Edition (DC Heath and Co.: Lexington) © 1991, p.

381.

66


TESTING TWO UNKNOWN SAMPLES OF FOOD FOR VARIOUS NUTRIENTS

Lab # _____ Date: ______________

Aim: To identify the nutrients in two unknown samples of food.

Apparatus:

5 test tubes

Test tube holder

Water bath

Iodine solution

Benedict’s solution

Dilute sodium hydroxide

Dilute hydrochloric acid

1% Copper sulphate solution

Methanol

Distilled water

Mortar and pestle

1 50mL beaker

Dropper

Spatula

2 unknown food samples

Method:

1. Label the test tubes A, B, C, D and E respectively.

2. Place 2cm3 of food sample 1 into each tube.

3. Carry out various food tests to identify Starch, Protein, Fats & Oils, Reducing sugars and

Non-reducing sugars.

4. Record your observations.

5. Repeat the procedure for food sample 2.

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Results:

Food sample 1

Test Observation Inference

Test for Starch: Add 2-3 drops of Iodine solution to the food sample.

Test for Protein: Add 2cm3 of NaOH solution to the sample. Add 2-3 drops of 1% CuSO4. Shake the contents of the tube.

Test for Fats & Oils: Add 5cm3 of methanol to the sample. Shake the contents of the tube and decant into a tube containing 5cm3 of distilled water.

Test for Reducing Sugar: Add 5cm3 of Benedict’s solution to the sample. Shake contents of the tube and place in a water bath for 5 minutes.

Test for Non-Reducing Sugar: Add 1cm3 of HCl to the sample. Place the tube in a water bath for 5 minutes. Allow the tube to cool and add NaOH drop wise until the fizzing stops. Add 5cm3 of Benedict’s solution and replace the tube in a water bath for 5 minutes.

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Food sample 2

Test Observation Inference

Test for Starch:

Test for Protein:

Test for Fats & Oils:

Test for Reducing Sugar:

Test for Non-Reducing Sugar:

Discussion:

1. What were the nutrients present in Food Sample 1?

2. Does this food most likely come from a plant or animal source? Explain.

3. What were the nutrients present in Food Sample 2?

4. Does this food most likely come from a plant or animal source? Explain.

5. List one possible source of error or precaution in this experiment.

Conclusion: Nutrients in two unknown samples of food were identified.

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Mark scheme: Testing two unknown samples of food for nutrients CRITERIA TESTED: ANALYSIS & INTERPRETATION

EVALUATES DATA

MARKS

(i) Correct inference based on the observation for each food test:

Sample 1 – Five Tests (5 x 1)

Sample 2 – Five Tests (5 x 1)

10

(ii) States a reason why food sample 1 is plant / animal based 2

(iii) States a reason why food sample 2 is plant / animal based 2

(iv) Lists one possible source of error / precaution 1

TOTAL 15

SYLLABUS COVERAGE: FOOD & NUTRITION


NEW DIAGRAMS

Diagram 1 Vertical Section of a Flower

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Diagram 2 Major Bones in the Human Body

72


Diagram 3 Cross Section of the Skin

© Ron Mahabalsingh 2015 - THE SCIENCE EXCHANGEintscience.weebly.com/uploads/1/3/3/6/13360003/supplement_2015.pdf · 110 THE HUMAN KIDNEYS A.6 EXCRETION New CROSS SECTION OF THE HUMAN

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