14/11/2018 Heating and Cooling W Richards Worthing High School

Heat and Temperature 14/11/2018 Heat is a type of energy that will flow from a warm area to a colder one. For example… This cup of coffee will ____ ____ because it is _____ ____ heat energy into the surroundings. This drink (taken out of the fridge) will _____ ___ because it is _____ ___ heat energy from the surroundings. Words – giving out, warm up, taking in, cool down

Heat energy 14/11/2018 How much heat energy an object has depends on its temperature AND how much of it there is… The sparkler is at a higher temperature than the bath, but the bath is MUCH heavier, so it has more heat energy.

Particle theory revision 14/11/2018 Particle theory is all about explaining the properties of solids, liquids and gases by looking at what the particles do. View animation SOLIDS In a solid the particles ______ around a _____ position. There is a ______ force of attraction between each particle and they are very _____ together Words – strong, close, vibrate, fixed

Words – fixed, collide, quickly, close, very, solids 14/11/2018 LIQUIDS GASES In a liquid the particles are _____ together but can move in any direction. They won’t keep a _____ shape like _____ do. In a gas the particles are _____ far apart and move _____ in all directions. They often ______ with each other and because they are far apart they can be easily compressed. Words – fixed, collide, quickly, close, very, solids

Heating a solid 14/11/2018 When a solid is heated it expands. We can use particle theory to explain why: View animation When a solid, liquid or gas heats up it will expand. When a solid, liquid or gas cools down it will contract.

Changes of state 14/11/2018 View animation

Changes of State 14/11/2018 What are these processes called? Choose from freezing, evaporating, melting, condensing

Heating ice 14/11/2018 Temp/OC 150 100 50 -50 This flat line shows where energy is being used to push the particles further apart for evaporation This flat line shows where energy is being used to break bonds – this has to be done during melting Time/s

Conduction 14/11/2018 CONDUCTION is when heat moves through a ________. Metals are better conductors of heat than plastic or wood. This is why… These parts are made of plastic or wood: These parts are made of metal:

Conduction 14/11/2018 In this experiment we saw that liquid water is a poor conductor of heat. The ice cube did not melt even though the water above it was boiling. Air is also a poor conductor of heat. This is how many types of house insulation and clothing keep us warm.

Words – sun, absorbs, nothing, warmer, waves Radiation 14/11/2018 When you wear a black t-shirt on a hot, sunny day you would feel ______ than if you wore white. This is because black ________ infrared radiation (i.e. heat) from the sun better than white does. I’m cool! I’m very hot! Conduction is when heat travels through a solid and convection happens in a liquid or gas, but radiation can happen through absolutely ________ because the heat is moving by ______. This is how heat reaches us from the ____. Words – sun, absorbs, nothing, warmer, waves

Words to use: expands, radiators, dense, heated, current, float Convection 14/11/2018 Convection is all about when a gas or liquid (“fluid”) moves and carries heat with it. When the fluid is heated it ____________. This means that it will become less __________ than the colder fluid around it. Because of this the warmer fluid will try to “_______” over the colder fluid, and this is why warm air rises. This is called a convection ___________. This is how heat reaches us from the ___________ in this room. Words to use: expands, radiators, dense, heated, current, float

Evaporation 14/11/2018 Heat can also be lost when water evaporates (this is how we cool off when we sweat): View animation This water will evaporate because the water molecules have enough energy to “escape” from the rest of the water. When they do so they will take heat with them.