Unit 4E Friction
Unit 4E Friction
QCA Suggested Activities
/ Extending and enriching activities/questionsShow children forcemetres and point out the spring inside them. Ask them to suggest how they work. Help children to practise reading the forcemeter eg when another child pulls on it, pulling open a drawer, dragging an object across the floor. Ask children to suggest whether it would be more or less difficult to get an object moving on a smooth or rough surface. Ask children how they might answer this question and. If appropriate, demonstrate using a forcemeter attached to an object eg a weighted margarine tub or a weighted shoe, how this question might be investigated. Discuss with the children what different forcemeter readings show. / ¨ use a range of forcemeters (calibrated in Newtons, range between 10n and 50n) and challenge the children to pull different forces eg 5n, 7n, 8n etc. Hide the scale to see if they can pull accurately.
¨ children use different forcemeters to try to pull exactly the same force on each one.
¨ predict force then pull various objects to check their predictions.
Ask children to investigate on which surfaces objects slide most easily. Present children with at least three different surfaces, and ask them what they think will happen. Help children to decide what to do and how to ensure their test is fair. Ask the children to present their results in a bar chart, helping them where appropriate. Discuss with the children the different methods they chose to investigate the question, and whether some were better than others for answering the question. Ask children to suggest what this work indicates about surfaces for roads, if cars and bicycles are to be safe and not slide / ¨ children could extend their work by investigating changing surfaces to allow objects to move more easily eg by coating the surface with different materials such as liquids, Vaseline, chalk etc.
¨ children should make their own suggestions about how they should test their ideas.
¨ link this work to everyday uses such as lubricants in engines, oil on bicycle chains
Unit 4E Friction
QCA Suggested Activities
/ Extending and enriching activities/questions¨ talk with children about surfaces between which there is a low or high friction and make a list showing everyday situations where high friction is helpful eg tyres on cars and bicycles, goalie gloves, tying shoe laces and everyday situations where low friction is useful eg skating, playground slides / ¨ children identify several places where friction is important in every day situations.
¨ extend the activity by thinking about situations where less friction is needed or where it can be a problem eg skating, bare patches on a ski slope etc.
¨ ask children to describe what it is like to walk through water eg in a swimming pool and to suggest why it is difficult. Elicit their ideas about why fish and boats can move through water. If necessary prompt them to think about shape. Show children a tall cylinder filled with water and talk with them about what they could do, using this apparatus and a small piece of plasticine, to find out which shapes move easily through water. Help children to decide what to measure egtime from dropping the plasticine into the cylinder until it gets halfway down or to the bottom and how to make the test fair egby always using the same piece of plasticine made into different shapes, always using the same height of water in the cylinder. Ask children to record results in a table and to interpret these in terms of the shape of the object and water resistance. Discuss children’s ideas with them. / ¨ extend this activity by comparing different liquids e.g liquid soap, orange juice, syrup etc
¨ do the shapes fall in a similar way through the air?
¨ make comparisons between air and water resistance
¨ take the children outside and ask them to run across the playground with a large sheet of card in front of them. Discuss what they can feel and ask them to try to explain what is happening. Extend the discussion to riding a bicycle into the wind or walking on a windy day. Demonstrate how the size of the surface affects how fast something falls through the air. / ¨ extension activities could include devising a test with varying materials to place on car windscreen, or as a spoiler to see the affect of a car travelling down a ramp. (Maybe motorised cars)
Unit 4E Friction
QCA Suggested Activities
/ Extending and enriching activities/questions¨ ask children to investigate parachutes egdoes the size of a parachute affect how long it takes to fall? Ask them what they plan to measure in order to answer the question. When children have made and recorded some measurements discuss them with the children and help them look for patterns in them. Help children to relate this to their understanding of air resistance. / ¨ children could carry out alternative investigation where they use their understanding about air resistance and parachute size to help them drop objects in a specific order. (Parachute Challenge)
¨ use a forcemeter to measure forces, reading the scale accurately
¨ explain that a bigger reading on the forcemeter shows it is more difficult to get an object moving than a smaller reading
/ ¨ use a variety of forcemeters eg 2.5N, 5N, 10N, 15N 30N etc. to measure the force needed to pull specific amounts. Describe the differences between each forcemeter.¨ find a range of objects to demonstrate differences in force needed to move objects.
¨ explain what they found out in terms of bigger/smaller forces and encourage the use of accurate measurements
¨ explain how the evidence collected answered the question, egif I have to make the slope steeper before it moves then the surface stops it sliding; or it will slide best on the surface where the reading on the forcemeter is smallest
¨ carry out a fair test
¨ make measurements and construct a bar chart which matches the measurements
¨ explain their results orally or in writing egby saying that the objects slid most easily on the smoothest surfaces. This is what I thought would happen
/ ¨ carry out test independently, making predictions, choosing variables and recognising fair test¨ record accurate measurements and construct bar chart to show results
¨ make comparisons between results
¨ explain their findings using results and make conclusions eg the smoother the surface the more easily the object moved
¨ group surfaces into ‘high friction’ and ‘low friction’
¨ given an everyday context egholding the handlebars on a bicycle or pulling a drawer out of a desk decide whether it is important for friction to be high or low
/ ¨ ask children to group different surfaces into 'high friction' and 'low friction' then order them from 'high' to 'low'¨ find examples of uses friction in every day life and compare these to examples of where friction is not useful
Unit 4E Friction
QCA Suggested Activities
/ Extending and enriching activities/questions¨ describe how they carried out a fair test
¨ identify which shapes move easily through water and explain this in terms of reduction of resistance
/ ¨ challenge the children to find a shape which moves more slowly through water, exploring a range of shapes to decide which type of shape works better than others¨ explain their results in terms of water resistance
¨ explain in terms of forces why you need to pull hard on a large surface, ega kite, an umbrella, a sail to hold it steady on a windy day egthe air/wind is pushing the umbrella up so I have to pull hard to hold it steady
/ ¨ ask children to demonstrate examples of air resistance and report their findings to the rest of the class¨ describe a fair test egI used a square parachute with the same weight each time and changed the size of the parachute
¨ make measurements of the time taken for the parachute to fall
¨ explain patterns in their results in terms of air resistance, egthe largest parachute took longest because it trapped most air which stopped it falling quickly
/ ¨ plan and record a fair test on parachutes making accurate measurements and using their results to reach conclusions¨ use what they have found out to answer the parachute challenge activity
Review work on friction by asking children to write and illustrate a story to show how friction is important. Read and talk about the stories with the children,
/ Review work by asking children to imagine what life would be like without friction. Would we be able to sit, walk, run etc? Children could write a story about the day friction gradually disappeared!1