Energy Revision - Physics Flashcards
(9 cards)
What are the energy stores?
Kinetic energy - this depends on the speed of the object.
Gravitational potential energy - this depends on the height of the object.
Thermal energy - this depends on the temperature of the object.
Chemical energy - transfer of energy from the chemical energy store occurs due to chemical reactions.
Elastic potential energy - depends on the amount of extension or compression.
What are the energy transfers?
Mechanical working – when a force is applied to move an object through a distance
Electrical working – when charge flows (electricity)
Heating – when energy is transferred between hotter and colder regions
Radiation – when energy is transferred as a wave, for example as light or sound
What is the Law of Conservation of Energy?
The Law of Conservation of Energy means that energy doesn’t appear or disappear and energy cannot be created or destroyed but energy can be transferred between different stores of energy.
What is the difference between temperature and heat?
Temperature is a measure of how hot something is however heat is a measure of the thermal energy contained in an object.
What is radiation?
All objects transfer energy to their surroundings by infrared radiation. The hotter the object, the more infrared radiation it emits.
What is conduction?
Conduction is where energy is transferred by the vibrating particles in a substance. The energy is transferred from a hotter region to a cooler region. Conduction happens fastest in solids because the particles are close together.
What is convection?
Convection happens when particles with a lot of thermal energy in a liquid or gas move, and take the place of particles with less thermal energy.
What is evaporation?
Evaporation happens when a liquid is heated. The heat gives the liquid’s molecules more energy. This energy causes the molecules to move faster. If they gain enough energy, the molecules near the surface break away. These molecules escape the liquid and enter the air as gas.
What is condensation?
Condensation happens when molecules in a gas cool down. As the molecules lose heat, they lose energy. As a result they slow down. They move closer to other gas molecules. Finally these molecules collect together to form a liquid.
