1 / 19
Télécharger la présentation

O.L.O.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. O.L.O. • To recap on our forces work from last week. • To be able to draw conclusions from last week’s experiment. • To learn about another force that acts in air. • To understand how the area of a piece of paper affects how quickly it falls.

  2. Forces Recap What do we remember from last week?

  3. A force in water • What is the name of the force that slows down objects sinking in water? • What is the name of the force that acts downwards on the sinking object?

  4. Water resistance in action… • When we jump into a swimming pool, it is water resistance that prevents us from hitting the bottom. • How can we make ourselves get to the bottom of the pool in the fastest time? Why?

  5. In the pool… • Have ever tried ‘running’ through water at the shallow end of the swimming pool? What is it like? Why? • Water resistance is the force which is responsible for making it difficult for us to move though the water.

  6. Surface area and Stream Lining… • The greater the surface area of the object, the more resistance it will get from the water. • If we spread our body out as we jump in the pool it will hit more water molecules. • The amount of water resistance pushing against him is great. • The swimmer will sink to the bottom of the pool much more slowly.

  7. Streamlined… • If we dive neatly into the water less water will hit us and we will get to the bottom of the pool faster. • We are in a streamlined position. • If we turned sideways we move through the water quicker. • A big splash (belly flop) more resistance… • A little splash (tight dive) less resistance…

  8. More streamlining • A float helps swimmers. Have you noticed how hard it is to swim if you stand the float up? • Swimmers can wear special suits made of lycra that help reduce the amount of water resistance. • The amount of W.R.on a dolphin, fish and boat are quite small – they are streamlined and can ‘cut through’ the water easier.

  9. What do our results tell us? • Which shape took the longest amount of time to sink to the bottom? Why? • Which shape took the shortest amount of time to sink to the bottom? Why? • Were your results what you expected? • You could try different liquids e.g. syrup

  10. Results and Conclusions • The shape which looked this ------------- took the longest time to sink. This is because it was w-----and therefore created a lot of water resistance. • The shape which looked like this -------took the shortest time to sink. It has less surface area. • The w------- the shape the s-------- it sinks.

  11. A force in air • What do we call the force that acts in air? • What does this force do to objects? • What is the name of the force acting in the opposite direction – downwards?

  12. Air Resistance • Air resistance is the force that pushes against a moving objects as they pass through the air. • It can act upwards and sideways. Give an example. • Like water resistance, it is a type of friction. • Air resistance slows you / objects down as they try to move through the air.

  13. Air resistance in action • Can you think of situations when you have experienced air resistance? • Riding your bike… how can you reduce the air resistance. • Running around in the playground…on what type of day is air resistance greater? • Riding downhill on a sledge… how can you make yourself go faster?

  14. More real life examples… • A water slide at a swimming pool or a slide in an adventure playground • A parachute… what happens when you open the parachute? Why is a parachute so large? • A dragster… Why does it need a parachute?

  15. Class experiments… • The running race… • Parachute games…keep it moving; swop places and cat and mouse.

  16. Predicting and Fair Testing • Which piece of paper will take the longest time to hit the ground? Why? • Which piece of paper will take the shortest time to hit the ground? Why? • What will be the one factor we will be changing? • What will we keep the same?

  17. Its your turn… • In 3s you are going to find out which size piece of paper takes the longest to fall. • You will need to give each other jobs. • Repeat 3 times and record your results. • Find something to stand on on the field.

  18. What do our results tell us? • Which piece of paper took the longest amount of time to hit the ground? Why? • Which piece of paper took the shortest amount of time to hit the ground? Why? • Were your results what you expected?

  19. Results and Conclusions • The g--------the area of the paper the f---- it falls to the ground. This is because there was more -------------. • The s------ the area of the paper the s---- it falls to the ground. This is because there was more -----------. • With a parachute, the w----- the canopy the s-----it falls to the ground.

More Related