Energy Flashcards
(40 cards)
What do you measure energy in
Joules
Kilojoules
State some examples of energy stores
Coal
Gas
Oil
Food
What do humans need energy for
Keep them warm
Let them move around
Breathe
Talk
Which people need more energy
Athletes
Why do people need to be careful with how much energy they take in
If they take more than they need or use, the body will store it as fat
What is the law of conservation of energy
Energy cannot be destroyed or created. It can only be transferred from one form to another
What is an energy store
Something that can store energy
How does burning conserve energy
Energy stored in fuel = Energy released from burning
How is energy transferred in a light bulb
Electricity -> Light and Heat
How is energy transferred in a motor
Electricity -> Kenetic and Heat
What is most energy wasted as
Heat
What does it mean when energy is dissipated
Energy that has been lost as heat to the surroundings
How can kinetic energy be stored
Using a flywheel
What is heat
A type of energy
What happens when particles heat up
They vibrate/move around faster and gain kinetic energy
What does the energy you need to
increase the temperature of a material depend on
The mass of material
Type of material
The temperature rise you want
Which way does heat flow from and to
From hot objects to cold objects
What happens when objects are the same temperature
They are in thermal equilibrium
What 3 ways can energy get from one place to another
Conduction
Convection
Infrared Radiation
Explain how conduction works
Particles vibrate when heated. These collide with other particles and transfer the heat energy
What materials are good conductors
Solids
Metals
Explain how convection works
Particles get heated and spread out. This makes them less dense and the rise. When they rise, they lose heat to the surroundings and cool down. Finally they become dense and sink
What materials are good at convection
Gases
Liquids
Explain how radiation works
Objects that have a temperature or are hot, emit infrared radiation
