Energy Transfer Flashcards
How can heat be transferred from place to place?
Conduction, Convection and Radiation
Which kind of surfaces are better at absorbing light?
Dark, matt surfaces are better at absorbing heat energy than light, shiny surfaces.
What does it mean to emit energy?
Give out energy.
What does it mean to absorb energy?
Take in energy.
What is another name for thermal radiation?
Infrared radiation.
What happens as an object gets hotter?
It emits more infrared radiation.
What type of radiation is infrared radiation?
Electromagnetic
How is radiation different to conduction and convection?
It can pass through the vacuum of space.
What does the kinetic particle theory explain?
The kinetic particle theory explains the properties of the different states of matter.
Explain the arrangement and movement of particles in solids.
They are close together and have a regular pattern. They vibrate about in a fixed position.
Explain the arrangement and movement of particles in liquids.
They are close together and are randomly spaced. They move around each other.
Explain the arrangement and movement of particles in gas.
They are far apart and randomly spread. They move quickly in any direction.
Name some of the properties of solids and why they are like this.
They have a fixed shape and cannot flow. They are like this because the particles cannot move from place to place. They cannot be compressed or squashed. They are like this because the particles are squashed and have no space to move into.
Name some of the properties of liquids and why they are like this.
They flow and take the shape of their container. They are like this because the particles move around each other. They cannot be compressed or squashed. They are like this because the particles are close together and have no space to move into.
Name some of the properties of gases and why they are like this.
They flow and completely fill their container. They are like this because the particles can move quickly in all directions. They can be compressed or squashed. They are like this because the particles are far apart and have space to move into.
How does heat energy move?
Conduction
What is a poor conductor of heat?
An insulator
What is the difference between non-metals, gases and metals?
Metals are good conductors of heat but non-metals and gases are usually poor conductors of heat.
When does convection occur?
Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection.
When do liquids and gases expand?
When they are heated. This is because the particles in liquids and gases move faster when they are hot as to when they are cold.
What are evaporation and condensation?
Changes of state.
What is evaporation?
Evaporation involves a liquid changing to a gas.
What is condensation?
Condensation involves a gas changing to a liquid.
When does the rate of condensation increase?
The rate of condensation increases if the temperature of the gas is decreased.
When does the rate of evaporation increase?
The rate of evaporation increases if the temperature of the liquid is increased. It is also increased if: the surface area of the liquid is increased or if air is moving over the surface of the liquid.
What are U - Values?
U-values measure the effectiveness of a material as an insulator in buildings.
If a material has a high U - Value, is it a good heat insulator?
No. The lower the U-value is, the better the material is as a heat insulator.
What is payback time?
The payback time of an energy-saving solution is a measure of how cost-effective it is. Here is the equation to calculate payback time: payback time (years) = cost of installation (£) ÷ savings per year in fuel costs (£) The payback time will be shortest if the cost of installation is low compared to the savings made each year.
What is temperature?
A measure of how hot something is. It is measured in Degrees Celsius.
What is heat?
A measure of the thermal energy contained in an object. It is measured in Joules.
What is Specific Heat Capacity?
The specific heat capacity of a substance is the amount of energy needed to change the temperature of 1 kg of the substance by 1°C.
Why does water have such a high Specific Heat Capacity?
Water has a particularly high specific heat capacity. This makes water useful for storing heat energy, and for transporting it around the home using central heating pipes.
What is the equation for working out Specific Heat Capacity?
E = m × c × θ E is the energy transferred in joules, J m is the mass of the substances in kg c is the specific heat capacity in J / kg °C θ (‘theta’) is the temperature change in degrees Celsius, °C
