Unit 3 - Lesson 9: Conservation of Energy & Energy Transfers Flashcards
Does energy have mass?
No. It is not a particle.
Energy cannot be created or destroyed. What do we call this?
The conservation of energy. We can also say that energy is conserved.
What does the conservation of energy mean?
The conservation of energy means if we need energy to power our car or help us run, that energy has to have come from somewhere else.
Can energy be stored?
Energy can remain in an energy store for millions of years or it can be transferred to a different store very quickly. We can store energy until we need it.
For example, the chemical energy stored in the bonds between the chemicals in your spaghetti will remain in that store until it’s transferred to you when you eat it. You may then use that energy for running. The chemical energy in the food has been transferred to helping you move (kinetic energy).
What is a Newton’s cradle?
A newton’s cradle demonstrates the conservation of energy. Energy is continuously transferred between the gravitational potential energy (GPE) store and the kinetic energy (KE) store. The energy is conserved. This means the amount of GPE in a ball is equal to the amount of KE in the ball it hits. The toy is called Newton’s cradle because it demonstrates Newton’s third law of motion: everything has an equal and opposite reaction.
Give a description of a chemical energy store.
The energy stored in the bonds between chemicals. This energy is released during reactions. This is often associated with energy obtained from organic matter (things that are or once were living).
Give a description of a kinetic energy store.
The energy an object has when moving.
Give a description of an electrostatic energy store.
The potential energy that exists when opposite charges build up separated from each other. The energy is released when the charges are released.
Give a description of gravitational potential energy stores.
When an object is raised higher off the ground, it gains potential energy to fall back to Earth. This is due to the gravitational field of the Earth.
Give a description of thermal (heat) energy stores.
This is heavily linked to kinetic energy. When a particle vibrates, it has kinetic energy. The more it vibrates, the hotter it becomes. A thermal energy store is when this heat is maintained. Heat can mean cold or hot temperatures.
Give a description of magnetic energy stores.
The energy stored in magnetised materials.
Give a description of elastic potential energy stores.
The energy stored in a stretched or squashed material.
Give a description of nuclear energy stores.
The energy stored within an atom’s nucleus. It’s released through the splitting or joining of these nuclei (plural for nucleus). This is usually associated with nuclear power and nuclear fusion in a star.
What four methods are there to transfer energy between stores?
- Mechanically - by a force acting on it
- Electrically - by charge moving in a potential difference
- By heating - energy transferred from hot to cold
- By radiation - the energy transferred by a wave (EM, light or sound)
Give an example of transferring energy by HEATING.
BUNSEN BURNER.
Here, chemical energy (the bonds of the gas) is being converted into thermal energy of the water being heated. The energy is transferred by heating (mainly conduction).
Give an example of transferring energy ELECTRICALLY.
ELECTRIC FAN.
Here, electrostatic energy (the power source) is transferred electrically to produce kinetic energy (the fan blades move).
