SATs - Science Exercise 16 - Physical Science Levels 5 - 7

Index
	Physical Science - Levels 5 - 7 - Answers [ Questions ]
	A top class sprinter can run the 100m race in 10 seconds. Calculate his average speed in m/s. Show your working. speed = distance/time = 100m / 10s = 10 m/s A clamp stand was set up as shown in the diagram. The rod of the stand was heated strongly. As it got hotter and hotter, the pointer moved from the zero on the scale over to its present position.
	Explain in terms of atoms, why this happened. When heated, atoms vibrate more and they push each other apart. They take up more space, causing the rod to expand
	What happens as the stand is allowed to cool? The atoms vibrate less, so pull closer together, causing the rod to contract
	When a gas is heated it will expand much more than a solid. Use your understanding of atoms and molecules to explain why this is so. Gases expand a lot because the forces between their atoms or molecules are very, very weak. Solids have very strong forces holding them as close together as possible


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Physical Science - Levels 5 - 7 - Answers