science ideas – forces

Session 1: background – what is energy? if something is happening, energy is involved

[required equipment- basic electronic kit, wind up torch, food packets, glue sticks, elastic bands, slingshots, matches, tea lights, solar power kit, propeller car kit]

[required printables - table with headings of energy types, table with columns for fuel types and calories, pictures of things for energy chains]

kids writing -

1. list of diff energy types seen in room in correct columns

2. chart of foods in order of energy stored

3. sticking an energy chain – transfer of energy

kids speriments -

1. seeing if can create all types of energy from electrical

2. burning candles, wind up torches ? see if solar power kit still works. slingshots, wind up cars

ideas behind

1. types of energy

movement energy – kinetic energy – if something is moving it has energy

light energy – if something is shining- sun/light it is giving out energy

sound energy – if something is giving out sound

heat energy

2.transferring energy

electric energy – energy can be transferred from one place to another using electric energy- switch on lamp on circuit = electric to light and heat. wind up torch = movement to electric to light and heat

make circuit to drive fan, make circuit to make noise – yep, electrical can carry energy that can become all of these things. this energy is the same.

3.storing energy -

strain energy [energy stored in something stretched, rubber bands

chemical energy – matches, batteries, food – look at calories.

gravitational energy – lift something up

energy is conserved, it is impossible to create or destroy energy

look at energy chains


session 2 and 3: what is a force, gravity

required equipment – string, 1 yoghurt pot per child, 2 large paperclips per child, 1 elastic band per child, skewer. spring balance, weights scale. cars, slope, surfaces, stop watch

required printables – diagram to make forcemeter. table to add info

kids writing – large paper and felt tip to make wall results chart

kids ‘speriments

1. making a forcemeter/newton meter

2. investigting gravity and friction

3. making an antigravity device

a. measuring force . making a forcemeter/newtonmeter

difference between mass and weight – mass on moon 1/6 here

weighing scales

b. how to design an experiment – hypothesis and idea of ‘fair test’

think of variables – mass of object [measure in newtonmeter], force applied – push; slope

?start with rolling cars flat and then down a slope – think about what happening. why start. how can we change the distance the car goes?

children to decide what to measure, how to make it a controlled experiment [a fair test]

small push – measure, large push – measure, low slope no push, steep slope no push.

us pushing, then gravity pulling in the flat and slope.

c.friction; if time, consider changing surface, and see what difference.

other friction – ice cube etc.

useful friction – breaks, running.

not useful – wearing things out, rope burns

turns kinetic energy into heat

3) the ‘reverse gravity cone’ ? in 2 if time [card board, 2 half circles of thin card per child, sellotape, scissors]

4) gravity vs the heart experiment! ? in 2 if time


session 4: resistance

density – upthrust, salty water etc.

ie dropping blobs of shaped blue tack in water and timing

required equipment – blue tac, stopwatch, tall glass or see through plastic jar, salt, water, straws

required printables – table of shapes and seconds

kids writing – large paper and felt tip to make wall results chart

kids ‘speriments

1. investigating which shapes sink most quickly

2. how to make a just sinker float

discussion – density, molecules differences in liquids solids and gases.

dropping the same shape, size and weight bluetac blob through air and water of the same distance- which will be quickest, and why

then can we alter the speed that it drops through air and water by altering shape? start with water. table of shapes and dropping speeds. which takes the longest, which takes the shortest, and discussion on why.

can we make our blue tac float? upthrust.

is shape the only determinant – can we make the water ‘heavier’ and will things then float better in it. [straw with blue tac blobs that just sink and add salt to water]


session 5 aerodynamics

[required ingredients – lots of A4 paper! wool, washers, paperclips, material squares – ? muslins and hankies, sellotape, paper aeroplane designs]

[required printables - paper aeroplane folds, newtons laws]

dropping things in air.

1. at the top of the stairs a tightly folded and sellotaped piece of paper vs a crumpled – which one falls the most quickly and why

2. make a parachute and drop.

at what height does it work best? how does it work? what can we vary – sizes of parachute, height dropped and weight.

what happens if the parachute is wet?

3. so does this design work for paper aeroplanes?

design and make some!

4. demonstrate conservation of energy – coin experiment / newtons cradle

end note

Newton’s Laws of Motion

what we have spent these 4 science lessons doing is showing how forces act, and that the forces require energy. we have looked at different types of energy, and then different forces. we have looked at ‘speeding up’ forces like gravity and pushing things, and ‘slowing down’ forces like resistance and friction

we have experimented with Newton’s Laws of Motion

I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

SO, if it is a toy car sitting on the floor, it won’t move unless you push it. If it is a bit of blue tack sinking through water it will carry on sinking until it is stopped by hitting the bottom. remember that friction itself is a force, and this slows things down.

II. The relationship between an object’s mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector.

this is a high tech one!! it means that you can calculate how much force was used to move something [how hard you pushed] if you know how much mass [kilograms] the object [toy car] had and how quickly it speeds ups. this is how scientists can work out how much rocket fuel is needed to get a spaceship into space! one day we will have a go at doing this.

III. For every action there is an equal and opposite reaction.

so when you are pushing that toy car, it is also pushing you back. but we are much bigger and heavier, and its not noticeable. but if you are in a swimming pool with floats and you stand on one and then try and step onto another, what happens? yep, you end in the water, because pushing yourself forward to stand on the new float sends the old one backwards, and you land in the middle!

Actually, he wrote it all in latin

Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.
Lex II: Mutationem motus proportionalem esse vi motrici impressae, et fieri secundum lineam rectam qua vis illa imprimitur.
Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales et in partes contrarias dirigi.

physics like this hopes to explain how the world, the universe and everything within it works. It doesn’t matter if we remember all the ‘rules’ and ‘laws’ , just that we have fun and know that they are there.

3 responses to “science ideas – forces

  1. How about negative energy and how that can be passed on from one family member to another? We could end with a discussion on positive thinking. ;-)

    Sounds great.

  2. yeah, well chloe did tell us all about negative energy… we will come to that later i think – in the shrink years!!

  3. Pingback: Petits Haricots · science wednesday

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