The Scientific Method What is Science? Science--organized way of using evidence to learn about the natural world Goals: –Investigate and understand natural.

The Scientific Method

What is Science?

• Science--organized way of using evidence to learn about the natural world

• Goals:– Investigate and

understand natural world to explain events.

– Use explanations to make useful predictions

Chemistry and Physics

• Chemistry- the branch of science that deals with the identification of the substances of which matter is composed

• Physics- the branch of science concerned with the nature and properties of matter and energy

Scientific Method

• An organized way of solving problems– 1.Observations and

questions– 2.Hypothesis– 3.Experimental procedure– 4.Record results– 5.Draw conclusions

#1 Observations/Questions

• 1.Observations/Questions – What you see– Inferences are your logical

interpretations of what you see.– Questions then arise…….– Why should I care?

• Observe that people on average are losing their hearing at an earlier age .

60,000 individuals under the age of 18 in the U.S. have severe hearing loss

#2 Hypothesis

• 2.Hypothesis-scientific and testable explanation for observations– “If……then……”– If people turn up their

headphones too loudly, then they will suffer hearing loss in time

#3 Procedure• 3.Experimental procedure- designed to test

hypothesis • Split subjects you are testing into groups:

#1 Experimental Group-given the experimental factor or changed in some way

#2 Control Group:-NOT changed

Experimental group with Experimental group with music turned up to high music turned up to high

volumevolume

Control GroupControl GroupMusic turned up just above Music turned up just above

hearing levelhearing level

#3 Procedure

• Variable-factor in experiment that is subject to change.– Independent variable- factor in experiment that’s

purposely changed and is independent of anything else—music volume

– Dependent variable —factor that a scientist observes for responses in because it depends on what the scientist did earlier—loss of hearing, sensitivity to sound, ringing in ears, etc.

– Only test ONE independent variable while having MANY constants.

#3 Procedure

• Must be a controlled, reproducible procedure

Testing effects of Testing effects of only ONE independentonly ONE independentvariable all the rest are variable all the rest are CONSTANT!!!!!CONSTANT!!!!!

Other scientists Other scientists need to be able to need to be able to reproduce it and reproduce it and find same results.find same results.

#3 ProcedureEXPERIMENT

EXPERIMENTAL GROUP

Check the resultsin time

CONTROL GROUP

Difference is the independent variable

Compare the dependent variable

Check the resultsin time

#4 Results

• 4. Results– Record data – Qualitative data -physical traits

(qualities) that can be described– Quantitative data -measurements

(quantities) that can be taken– Pictures, tables, graphs– Trends noticed

#4 Results

Qualitative? Quantitative?

Experimental group: Control group: music turned up to music turned up just high volume above hearing level

#4 Results

• When you graph data:– Independent

variable goes on the x-axis (volume)

– The dependent variable goes on the y-axis (hearing sensitivity level)

x-axis volumey-a

xis h

earin

g se

nsitiv

ity le

vel

Must be even increments

#4 Results

• Precision vs. Accuracy– Precision- describes

how closely measurements are to one another

– Accuracy- compares a measurement to a real or accepted standard

#5 Conclusions

• 5.Conclusions– Hypothesis is either supported or

rejected. NEVER “PROVEN!”– If supported further testing – If rejected hypothesis changed and

tested again– Can be partly true– Findings always useful!!!

• Conclusion?

Hypothesis supported: loud music is one of the most common causes of hearing loss

Overview

State the Question or Problem

Form a Hypothesis

Set Up a Controlled Experiment

Record Results

Draw a Conclusion

Publish Results

Ethics

• When experiments are not possible– Animals in natural

habitat– Ethical concerns

Scientific Theories• Theory-a well-supported explanation of some

aspect of the natural world– ***It’s the closest you can get to scientific fact;

not a guess – It’s a hypothesis than has been tested and

supported many times– Used to make future predictions– If contradictory evidence found, theory revised or

replaced– There is no evidence against them

• A hypothesis is a POSSIBLE explanation, whereas a theory IS an explanation

Scientists’ Tools

• Common measurement system– Metric system or (SI)- a

measurement system used worldwide by scientists based on multiples of 10•Mass-grams (g)•Volume-liters (L)•Distance-meters (m)•Temperature- Kelvin (K) or

Celsius (OC)

Temperature• Fahrenheit scale- water

freezes at 32oF and boils at 212oF

• Celsius scale- 0oC is the freezing point of water and 100oC is the boiling point

F = (9)C + 32 5 • “30 is hot. 20 is nice. 10 put a coat on, 0 is ice.”

Temperature

• Kelvin is the actual metric scale for temp where 0 K is absolute zero and the coldest possible temperature equal to -273oC

K = 273 + oCWater freezes at 0oC

which is = 273K

Volume and Density

• Volume= length X width X height• Density= mass (g) volume (L)• Density video

Which is more dense?

http://www.stevespanglerscience.com/experiment/seven-layer-density-column

Kilo Hecto

Deka

UNITS

Gram

Liter

Meter

UNITS

deci centi

milli

Metric to Metric Map

“Use it and you will never get lost!”

How To Use Your Map

1) Start at the unit/prefix given to you (starting point).2) Count the number of steps/places to the unit/prefix you want

(final destination)each is a factor of 10.3) Move the decimal point the number of steps/places in the

same direction.

SMALLESTLARGEST

Kilo Hecto

Deka Gram deci centi

milli

Check for Understanding

How many mg are in 3.6 Kg?

Starting point Final Destination

3,600,000 mg6 places to the right of the decimal point

Kilo Hecto

Deka Meter deci centi

milli


How many hm are in 12.67 mm?

Starting pointFinal Destination

0.0001267 hm5 places to the left of the decimal point

Helpful Mnemonic

Try to create your own mnemonic to help you remember the prefixes and their order. This will be important because you will not receive the

metric map on your quiz.

Kings Have Diamonds

BUT Diamonds

Cost Money

Scientific Notation• Sometimes numbers are too big or too small

to write with ease and clarity– The Andromeda Galaxy (the closest one to our

Milky Way galaxy) contains at least 200,000,000,000 stars.

– The weight of an alpha particle, which is emitted in the radioactive decay of Plutonium-239, is0.000,000,000,000,000,000,000,000,006,645 kilograms.

• Scientific notation is used to express these large or small numbers in a convenient way

• Remember that:– 100 = 10 X 10 = 102

– 1000 = 10 X 10 X 10 = 103

– 10,000 = 10 X 10 X 10 X 10 = 104

ExampleWrite 4,776 in scientific notation

Place the decimal immediately to the right of the left-most non-zero number. This should give you a number between

one and ten.

4.776Count the number of digits between the old and the new

decimal point, this gives the power, n of 10 (10n).

4 776 X 103

Since the decimal is shifted to the left, the exponent is positive.

4.776 x 103

3 Digits


Write 0.0246 in scientific notation Place the decimal immediately to the right of the left-most non-zero number. This should give you a number between

one and ten

2.46Count the number of digits between the old and the new

decimal point, this gives the power, n of 10 (10n).

X 10-2

Since the decimal is shifted to the right, the exponent is negative.

2.46 x 10-2

2 Digits

0 02 46


Write 4.953 x 104 in standard form Write the decimal number.

4.953Move the decimal the number of places specified by the powers of ten: to the right since it is positive.

X 104 4 9530Rewrite the number in integer/standard form.

49,530

4 Places

Write 8.397 x 10-1 in standard form

Write the decimal number.

8.397Move the decimal the number of places specified by

the powers of ten: to the left since it is negative.

X 10-1 0 8 397Rewrite the number in integer/standard form.

0.8397

1 Place

Multiplying and Dividing With Your Calculator

1. Punch the number (the digit number) into your calculator.

2. Push the EE or EXP button. Do NOT use the x (times) button!!

3. Enter the exponent number. Use the +/- button to change its sign.

4. Voila! Treat this number normally in all subsequent calculations.


• You can use scientific notation to complete calculations without a calculator for ridiculously huge numbers

• Example• Multiply 2,500,000,000,000,000 times

4,000,000,000Answer?


• You can use scientific notation to complete calculations without a calculator for ridiculously huge numbers

• Example• Multiply 2,500,000,000,000,000 times

4,000,000,000Answer? 1 X 1025

1. Read the question. The question will provide you with information that identifies your starting point and your final destination.

• Starting point = the number and unit provided by the question

• Final destination = the units desired after converting

2. Write your starting point and your final destination.3. Determine how you will get from your starting point to

your final destination (simply find “connections” or conversion factors between your starting and final unit).

Metric to US Conversion Steps(Dimensional Analysis)

Metric to US Conversion Steps(Dimensional Analysis)

4. Create a fraction with your starting point.5. Write in the bottom unit of the new fraction. This should be the same as the top unit of the previous fraction.6. Write one set of “connections” or conversion factors into the fraction. Your bottom unit will guide you.7. Ask yourself, “Do I have the desired unit (final destination) on the top of the new fraction?”

NO YES

8. Cancel any units that are diagonal. (This should leave you with only the units that represent your final destination)9. Multiply the top of the fractions…multiply the bottom of the fractions…divide the top by the bottom.

(Go back to step 5) (Proceed to step 8)

Practice Conversions

1. How many seconds are in 6 minutes?

2. How many centimeters are in 27 inches?

3. If a truck weighs 15,356 pounds, how many tons is it?

4. If you had 10.5 gallons of milk, how many pints would you have?

5. Students go to school for 180 days. How many minutes is this equal to?

How many seconds are in 6 minutes?

6 minutes seconds

(6 minutes)1

( )( )

secondsminute

360 seconds

601

=(6)(60 seconds)

(1)(1)

=

Step 1 – Read the question and determine

what information it provides you with (starting point & final destination)

Step 2 – Write down your starting point and your final

destination1 minute = 60 secondsStep 3 –

Determine how you will

getfrom your

starting point to your final destination

(list any “connections” or conversion

factors) Step 4 – Create a fraction with your starting point

Step 5 – Write in the bottom unit of the new fraction (this is the same as the top unit of

your previous fraction)

Step 6 – Write the appropriate conversion

factor into the fraction. Your bottom unit will guide you.

Step 7 – Determine if this top unit is the desired unit (your

final destination). In this case the answer is YES, so

we move on to step 9

Step 8 – Cancel all diagonal units. Once this is done,

your final destination should be the only unit left – in this

case seconds

Step 9 – Multiply the top of the fractions; multiply the bottom of the fractions;

divide the product of the top by the product of the bottom

Starting Point

Final Destination

How many centimeters are in 27 inches?

27 inches centimeters

(27 inches)1

( )( )

cminch

68.58 centimeters

2.541

= (27)(2.54 cm)(1)(1)

=




destination1 inch = 2.54 centimetersStep 3 – Determine

how you will get

from your starting

point to your final

destination (list any

“connections” or

conversion factors)

Step 4 – Create a fraction by placing your starting

point over one










case centimeters



Starting Point

Final Destination

If a truck weighs 15,356 pounds, how many tons is it?

15,356 pounds tons

(15,356 lbs.)1

( )( )

tonlbs.

7.678 tons

12000

=(15,356)(1 ton)

(1)(2000)

=




destination2000 pounds = 1 tonStep 3 – Determine

how you will get

from your starting point to your final destination


factors) Step 4 – Create a fraction by placing your starting

point over one










case tonsStep 9 – Multiply the top of the fractions; multiply the bottom of the fractions;


Starting Point

Final Destination

If you had 10.5 gallons of milk, how many pints would you have?

10.5 gallons pints

(10.5 gallons)1

( )( )

quartsgallon

84 pints

41

=(10.5)(4)(2 pints)

(1)(1)(1) =




destination

1 gallon = 4 quarts1 quart = 2 pintsStep 3 –


getfrom your




point over one






final destination). In this case the answer is NO, so we

move back to step 5



case pints


divide the product of the top by the product of the

bottom

Starting Point

Final Destination

( )( )

pintsquart

21








Students go to school for 180 days. How many minutes is this equal to?

180 days minutes

(180 days)1

( )( )

hoursday

259,200 minutes

241

=(180)(24)(60 minutes)

(1)(1)(1) =




destination

1 day = 24 hours1 hour = 60 minutesStep 3 –


getfrom your




point over one






final destination). In this case the answer is NO, so we

move back to step 5

Step 9 – Cancel all diagonal units. Once this is done, your final destination should be the

only unit left – in this case minutes

Step 9 – Multiply the top of the fractions; multiply

the bottom of the fractions; divide the

product of the top by the product of the bottom

Starting Point

Final Destination

( )( )

minuteshour

601








The Scientific Method What is Science? Science--organized way of using evidence to learn about the natural world Goals: –Investigate and understand natural.

Documents

hearing level

earlierloss of hearing

independent variable

experimental factor

severe hearing loss

common causes of hearing

independent variablecompare

experimental procedure4