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The aim of this task is to enable you to explore the ideas your pupils hold aboutimportant concepts in science. Many pupils bring to science lessons a range ofalternative meanings for terms and differing understandings of importantscientific concepts. These differing meanings and understandings are oftenreferred to as misconceptions, alternative frameworks or alternativeconceptions.
In preparation for this unit you are asked to spend some time exploring whatideas your pupils hold about important scientific ideas. Use the pre-unit tasksheets for pupils and teachers as a means of doing this. Your analysis of theirresponses will be the focus of a discussion during Session 1. You will receivecopies of these task sheets from your Key Stage 3 science consultant.
Collecting evidence
Carry out the task first with a class of pupils in Year 7. A minimum of 20 pupilsshould complete Pre-unit Pupil’s Task Sheet 1.
Explain to them that this is not a test. They should not feel threatened by theexperience. You are not checking up on what they know. Marks will not berecorded for future use in school. Explain that the task is to be used to help findout what they THINK about scientific ideas, and that their responses will helpplan future lessons.
Ask them to read through each statement, and indicate whether they ‘agree’,‘disagree’, or are ‘not sure’ about whether it is correct. Collect the sheets in.There is no need to ‘go over’ the right answers with the pupils. However, thistype of activity is useful for discussion and many pupils want to know if they areright, and to argue their reasons with peers who selected differently. You mustdecide, at the outset, whether you are going to allow time for such a discussion.
Carry out the same activity with a class of pupils in Year 9, of similar ability.
Analysis
Each of the statements on the sheet represents a common misconception heldby pupils.
Count up and record the number of ‘agree’, ‘disagree’ and ‘not sure’ selectionsthe pupils have made. Complete Pre-unit Teacher Task Sheet 2.
This will give an indication of the degree to which your own pupils hold the ideasoutlined on the pupil task sheet.
What are the three most commonly held alternative conceptions(misconceptions) in each year group?
Compare the responses from Years 7 and 9.
Are there any similarities or differences in the misconceptions of the two year groups?
Is there any evidence of a reduction in the extent of the misconceptions?
Bring the results of your pre-unit task to the training.
The school is an 11–16 comprehensive in a small, rural town in thenorth of England. The school population is approximately 650.Very few pupils are entitled to free school meals. About 30% ofpupils are on the special educational needs register.
Organisation
The pupils are set for science. The class on the video is in Year 8,the 2nd set out of 5.
The school has been a CASE school for a year and these pupilshave been taught CASE lessons regularly since they were in Year 7. They are used to working in this way. The groups are self-selected friendship groups.
On the day of filming, 22 out of 28 pupils were present – 14 boysand 8 girls. The high level of absence was largely due to the fact itwas the last day of the half term and some pupils had gone onholiday early.
The lesson filmed was a 90 minute timetabled lesson. It has beenedited to make it possible to show the lesson’s features in atraining session.
The lesson is based on Unit 8I ‘Heating and cooling’, from the QCA scheme ofwork. The teacher has modified the possible teaching activities to provide afocus on teaching thinking.
Objectives
• To use the particle model to explain changes of state and know thatchanges of state occur at a fixed temperature
• To use thinking skills
Teaching strategy
Introduction
The teacher explains the objectives of the lesson and links to prior learning;details of how to complete the task and what the expectations are.
Main part of lesson
Pupils work in groups, completing the tasks and producing a group answer.
Activities
All recording by the pupils was carried out on a prepared worksheet.
1. Pupils predict what will happen as a substance cools. They complete andsketch a graph and explain why they have chosen that shape.
2. They are provided with liquid stearic acid and water or Vaseline at 80oC. As itcools (in a container of ice), they record the temperature every 30 secondstogether with any observations.
3. The results are graphed.
4. Pupils compare the outcomes with the prediction and record theirconclusions giving reasons and/or using precise language (reasoning skills).
5. In discussion groups, pupils produce a model to explain their results.
Plenary
The teacher manages the class discussion, enabling pupils to argue, articulateand justify their findings. The final summary enables pupils to reflect on whatthey have learned, the way they think and look forward to future developmentsof this topic.
A ‘good enough’ version of the billiard ball model to explain a range of physical phenomena
Basic premises
• All matter consists of tiny particles.
• Types of particle vary in their volume.
• Types of particle vary in their mass.
A crystalline solid has a set shape and a fixed volume that is independent of thatof its container. To represent this the particles in the particle model:
• are arranged in rows and sheets;
• are close together;
• are held together tightly;
• have energy and vibrate around a point;
• cannot easily change places.
A liquid has a fixed volume and takes up the shape of its container up to thelevel of the surface of the liquid. To represent this the particles in the particlemodel:
• have no set pattern;
• are also close together;
• are not so tightly held together as in a solid;
• have more energy and move randomly;
• can change places.
A gas takes up the whole volume of its container. If that container is open, it willdiffuse into the air. To represent this the particles in the particle model:
• are not arranged in any way;
• are far apart;
• are very weakly held together;
• have much more energy and move very rapidly in all directions;
• constantly change places in no pattern.
Note: the distance between particles in air is about nine diameters.
Developing a sequence of ‘good enough’ cell models
Handout 4.7
Teaching model
Plastic bag filled withwater or jelly and atable tennis ball
Plastic bag filled withwallpaper paste(shows vacuole)placed in jar (showscell wall)
Different materials canbe used to show howcells are specialisedand adapted to theirfunction such asballoons for guardcells, football for eggand marble with tail forsperm (to showrelative size)
Plastic bag cellsplaced in fish tank toshow tissue; comparethis with looking downthe microscope to seelayers
Visking tubing andparticle-sieve models
Nucleus made ofjumble of pipecleaners, animations
Can be used toexplain
All living things havesimilar structures
Differences betweenplant and animal cells
Differences in cell formreflect their functions
Tissue under themicroscope containsmany cells that are thesame
Gas exchange in thelungs, respiration,digestion, wateruptake in root hair,photosynthesis
Reproduction andgrowth
Scientific idea
The cell is the basicbuilding block of livingmaterial, consisting ofnucleus, cytoplasmand membrane
Plant cells also have acell wall and vacuole
Cells are adapted totheir function and havespecialised forms
Tissue is composed ofgroups of the sametype of cells anddifferent tissues canform organs
The cell membrane isdifferentiallypermeable
Nucleus containsgenetic material andcan divide causing celldivision
Alternative approaches to teaching energy at Key Stage 3
Energy transfer
In this approach the energy is located in one place, and when somethinghappens energy is transferred from that place to another.
Typical language to use:‘The energy in the battery is transferred to the bulb by electricity and then fromthe bulb to the surroundings by heating and light.
‘Energy from the Sun is transferred to the leaf cells by light.’
‘Energy is transferred from the reaction between magnesium and hydrochloricacid to the surroundings by heating.’
‘A weightlifter transfers energy from his muscles to the bar by lifting (moving)his arms.’
Energy transformation
Here energy takes on different forms, for example chemical, heat, light, etc.Energy is transformed or changed from one form or type to another when achange occurs. In this approach teachers use words such as ‘changed’ or‘converted’.
Typical language to use:‘The chemical energy in the battery is transformed into electrical energy inthe wires and then to light energy and heat in the bulb.’
‘The light energy from the Sun is changed into chemical energy in the leaf.’
‘Chemical energy in the magnesium and hydrochloric acid is changed intoheat when they react together.’
‘The chemical energy in the weightlifter’s muscles is changed into kineticenergy when lifting the bar and is changed into potential energy at the topof the lift.’
Neither of these approaches is right or wrong. The two points of substance arethat:
• pupils need to be aware that either energy transfer or energy transformationmight be used in different Key Stage 3 text books, tests or examinations;
• teachers in a science department need to adopt a consistent approach toteaching energy across the science curriculum.
‘ … there is a certain quantity,which we call energy, that does notchange in all the manifold changeswhich nature undergoes.
That is a most abstract idea,because it is a mathematicalprinciple: it says that there is anumerical quantity, which does notchange when something happens.It is not a description of amechanism, or anything concrete:it is just a strange fact that we cancalculate some number and whenwe finish watching nature gothrough her tricks and calculatethat number again it is the same.’
‘Imagine Dennis who has blocks that areabsolutely indestructible and cannot bedivided into pieces. Each is the same asthe other. Let us suppose he has 28.
His mother puts him with his 28 blocks intoa room at the beginning of the day.
At the end of each day, being curious, shecounts them and discovers a phenomenallaw. No matter what he does with theblocks, there are always 28 remaining.
This continues for some time until one dayshe only counts 27, but with a little searching she finds one under a rug. Sherealises she must be careful to look everywhere.
One day later she can only find 26. She looks everywhere in the room, butcannot find them. Then she realises the window is open and the two blocks arefound outside in the garden.
Another day, careful counts show there are 33 blocks. This causesconsiderable dismay until it is realised that Bruce came to visit bringing hisblocks with him and left a few.
She removes the five extra blocks and gives them back to Bruce and all returnsto normal.
We can think of energy like this except there are no blocks.’
We can use this idea to track energy transfers during changes. We need to becareful to look everywhere to ensure that we can account for all the energy.
Source: Primary School Teachers’ and ScienceProject 1991 – Pack 2 Understanding Energy,published by Oxford University Department ofEducational Studies and Westminster CollegeOxford ISBN 0 903535 11 4
1. Draw a huge leaf in chalk in the playground/hall with gaps for pupils to get inand out.
2. Assign pupils different tasks:
• At least one pupil outside the leaf holds three trays containing cards forwater, carbon dioxide and oxygen.
• At least one pupil inside the leaf holds a tray containing cards for sugar.
• At least one pupil will carry out photosynthesis only in the light.
• At least three pupils carry cards into and out of the leaf.
• Two pupils stand round the leaf and shine torches to represent daytime.
• The remaining pupils are observers and write down what is happeningduring the day and night.
3. Give pupils a job description and explain what they have to do. Start withnight-time, use freeze-frame to check pupils understand what they aredoing. (Freeze-frame: Call ‘freeze’ and pupils stop; ask some of the pupils toexplain what job they are doing and the observers to describe what ishappening overall.)
4. Turn the torches on and start the game.
5. Run through day and night a few times to check everyone understands.
6. Extension:
• If pupils have learned that plants respire all the time as well asphotosynthesising during the day, this process can be included. Thepupils that represent respiration will be active even when the torches areswitched off.
• Ask pupils to find fault with the model, e.g. the leaf does not take inwater from the atmosphere (unless it’s an airplant).
These are the cards to use. They Velcro together and are written on both sides:
front: back: front: back:
front: back:
The respirers split the velcro of sugar and turn over all the half cards to putwater together: su gar + oxygen ➝ wa ter + carbon dioxide
The photosynthesisers split the Velcro of water and turn over all the half cardsto put sugar together: wa ter + carbon dioxide ➝ su gar + oxygen
Weathering C, P, B Chemical attack; physical breakdown; organisms having physical and chemical effects
Erosion and P, C Physical movement of material; chemical transport transport in solution
Deposition P, C, B Physical deposition, e.g. by slowing currents; chemical deposition, e.g. when saline waters evaporate; biological deposition, e.g. by trees falling into coal swamps
Compaction and P, C Physical compaction; chemical crystallisation of cementation natural cements
Metamorphism P, [C] Change without melting due to increased heat and/or pressure [while new minerals, chemically different from the originals may form, the bulk chemistry of the rock remains unchanged]
Melting P Change of state due to changes in temperature and/or pressure [but chemical changes can result from partial melting, since different minerals melt at different temperatures]
Rising P Rising of magma from hot to cooler regions, since magma has lower density than the surrounding rock
Crystallisation P, C Physical change of state from liquid to solid as under the Earth’s chemicals slowly crystallise into mineral surface compounds
Extrusion (as P, C Physical change of state from liquid to solid as lava, ash, chemicals quickly crystallise into mineral bombs, etc.) compounds
Uplift P Rock sequences rising due to Earth movements
Deformation P Folding = plastic deformation, faulting = brittle (folding, faulting, deformation, metamorphism as abovemetamorphism)