| Systems warm up when energy is transferred to their thermal energy store. | Energy Transfer for Warming Up |
| What happens when energy is transferred to a system's thermal energy store? | The system warms up. |
| Systems cool down when energy is transferred out of their thermal energy store. | Energy Transfer for Cooling Down |
| What happens when energy is transferred out of a system's thermal energy store? | The system cools down. |
| Some systems need more energy than others to warm up because they are made of different substances. | Varying Energy Requirements |
| Why do some systems need more energy than others to warm up? | Because they are made of different substances. |
| It takes 130 J of energy to raise the temperature of 1 kg of gold by 1°C. | Energy to Raise Gold Temperature |
| How much energy is needed to raise the temperature of 1 kg of gold by 1°C? | 130 J of energy. |
| It takes 4200 J of energy to raise the temperature of 1 kg of water by 1°C. | Energy to Raise Water Temperature |
| How much energy is needed to raise the temperature of 1 kg of water by 1°C? | 4200 J of energy. |
| 1 kg of gold will warm up faster than 1 kg of water. | Comparison of Warming Speeds |
| Which will warm up faster, 1 kg of gold or 1 kg of water? | 1 kg of gold. |
| 1 kg of water can store more thermal energy than 1 kg of gold. | Thermal Energy Storage Comparison |
| Which can store more thermal energy, 1 kg of water or 1 kg of gold? | 1 kg of water. |
| Every substance has a specific heat capacity. | Specific Heat Capacity |
| What does specific heat capacity refer to? | The amount of energy it takes to raise the temperature of 1 kg of a substance by 1°C. |
| It takes 4200 J of energy to raise the temperature of 1 kg of water by 1°C. | Energy to Raise Water Temperature |
| How much energy is needed to raise the temperature of 1 kg of water by 1°C? | 4200 J of energy. |
| The specific heat capacity of water is 4200 J/kg°C. | Specific Heat Capacity of Water |
| What is the specific heat capacity of water? | 4200 J/kg°C. |
| Specific heat capacity is measured in joules per kilogram degree Celsius (J/kg°C). | Unit of Specific Heat Capacity |
| In what units is specific heat capacity measured? | Joules per kilogram degree Celsius (J/kg°C). |
| You can calculate the amount of thermal energy stored in a system after warming or cooling. | Calculating Thermal Energy |
| How do you calculate the change in the amount of thermal energy stored by a system? | Use the equation: Δ? = ? × ? × Δθ |
| For example, this is how to calculate the change in thermal energy when 0.5 kg of water is heated from 20°C to 50°C: | Example Calculation (Heating) |
| What happens to the thermal energy store when 0.5 kg of water is heated from 20°C to 50°C? | The water gains energy in its thermal energy store. |
| If 0.5 kg of water cools from 20°C to 5°C, the water would lose energy from its thermal energy store. | Example Calculation (Cooling) |
| What happens to the thermal energy store when 0.5 kg of water cools from 20°C to 5°C? | The water loses energy from its thermal energy store. |
| When cooling, the change in temperature and the change in thermal energy are negative. | Negative Change in Temperature |
| Why is the change in thermal energy negative when water cools down? | Because the change in temperature is negative, leading to a negative change in thermal energy. |
| A system needs an energy input in order to change state. | Energy Input for State Change |
| What is the energy needed for a substance to change state called? | Latent heat. |
| When a substance changes state, the energy supplied increases the internal energy stored. However, it does not change the temperature of the substance. | Internal Energy Increase |
| What happens to the internal energy and temperature when a substance changes state? | The internal energy increases, but the temperature does not change. |
| The specific latent heat of a substance is the energy required to change the state of 1 kg of the substance with no change in temperature. | Specific Latent Heat |
| What is the specific latent heat of a substance? | The energy required to change the state of 1 kg of the substance with no change in temperature. |
| To calculate the energy needed to change the state of a substance we use this equation: | Equation for Energy Needed |
| What equation is used to calculate the energy needed to change the state of a substance? | Mass × specific latent heat. |
| The unit of specific latent heat is joules per kilogram (J/kg). | Unit of Specific Latent Heat |
| In what units is specific latent heat measured? | Joules per kilogram (J/kg). |
| Thermal insulation helps to reduce unwanted energy transfer. | Thermal Insulation |
| What is a good example of thermal insulation to reduce unwanted energy transfer? | Buildings. |
| Buildings are often heated so that they are warm enough to live and work in. | Heating Buildings |
| Why are buildings heated? | To make them warm enough to live and work in. |
| Buildings lose heat to their surroundings. | Heat Loss in Buildings |
| What happens to the heat in buildings? | It is lost to their surroundings. |
| Many buildings use thermal insulation to reduce the rate of cooling. One example is an air gap between two walls, filled with a poor conductor like foam. | Reducing Rate of Cooling |
| How can buildings reduce the rate of cooling? | By using thermal insulation such as an air gap between two walls, filled with a poor conductor like foam. |
| Other examples in buildings include loft insulation and double glazing of windows. | Other Thermal Insulation Examples |
| What are other examples of thermal insulation in buildings? | Loft insulation and double glazing of windows. |
| In all of these examples, materials that are poor conductors are used to minimise energy transfers. | Materials Used in Thermal Insulation |
| Why are poor conductors used in thermal insulation? | To minimize energy transfers. |
