This lesson covers:
- The seven main energy stores
- How energy can be transferred between different stores
- Examples of energy transfers between stores
Seven main energy stores
There are seven main types of energy stores.
- Gravitational potential energy store – objects raised above ground level.
- Kinetic (movement) energy store – moving objects.
- Elastic potential energy store – stretched or compressed objects.
- Chemical energy store – food, fuel, batteries.
- Magnetic energy store – magnets.
- Electrostatic energy store – electric charges.
- Thermal energy store – objects when they release heat.
Energy transfers between stores
When something happens to an object, energy is transferred from one store to another.
There are four main ways energy can be transferred:
- Mechanically – through forces causing movement.
- By heating – from hotter to colder objects.
- Electrically – charges moving in a circuit.
- By radiating – waves carrying energy.
Examples of energy transfers – elastic potential to kinetic
Elastic potential to kinetic:
When a ball springs off a trampoline, energy transfers from the trampoline’s elastic potential store to the ball’s kinetic store.
Examples of energy transfers – kinetic to gravitational potential
Kinetic to gravitational potential:
When a ball rolls down a hill and then off of a ramp, kinetic energy transfers to gravitational potential energy.
Examples of energy transfers – chemical to light and thermal
Chemical to light and thermal:
When burning fuels, energy is transferred from chemical stores to the thermal store. Some energy is radiated as light.
PRACTICE QUIZ
1. What are the seven main energy stores?
Answer: The seven main energy stores are gravitational potential energy, kinetic energy, elastic potential energy, chemical energy, magnetic energy, electrostatic energy, and thermal energy.
2. What is gravitational potential energy?
Answer: Gravitational potential energy is the energy stored in an object due to its height above the ground. The higher the object, the more gravitational potential energy it has.
3. What is kinetic energy?
Answer: Kinetic energy is the energy of motion. Any moving object possesses kinetic energy, which depends on its mass and velocity.
4. What is elastic potential energy?
Answer: Elastic potential energy is the energy stored in objects that can be stretched or compressed, such as springs or rubber bands.
5. What is chemical energy?
Answer: Chemical energy is the energy stored in chemical bonds within molecules. It is released during chemical reactions, such as burning fuel or digesting food.
6. What is magnetic energy?
Answer: Magnetic energy is the energy stored in magnetic fields. It is associated with the positions and interactions of magnets or magnetic materials.
7. What is electrostatic energy?
Answer: Electrostatic energy is the energy stored in electric charges due to their positions relative to each other. Like charges repel, and opposite charges attract, storing energy in the system.
8. What is thermal energy?
Answer: Thermal energy, or heat energy, is the energy that comes from the temperature of an object. It is due to the kinetic energy of the particles within the object.
9. How is energy transferred mechanically?
Answer: Energy is transferred mechanically when a force causes an object to move. This transfer can be seen in actions like pushing, pulling, or lifting.
10. How is energy transferred by heating?
Answer: Energy is transferred by heating from a hotter object to a cooler one, usually through conduction, convection, or radiation.
11. How is energy transferred electrically?
Answer: Energy is transferred electrically when electric charges move through a circuit, such as when a battery powers a light bulb.
12. How is energy transferred by radiation?
Answer: Energy is transferred by radiation through electromagnetic waves, such as light, infrared, or radio waves, without the need for a medium.
13. What is an example of energy transfer from elastic potential to kinetic energy?
Answer: An example is a ball springing off a trampoline. The elastic potential energy in the trampoline transfers to the ball’s kinetic energy as it moves upwards.
14. What is an example of energy transfer from kinetic to gravitational potential energy?
Answer: An example is a ball rolling up a hill. As it moves up, its kinetic energy converts to gravitational potential energy.
15. What is an example of energy transfer from chemical to thermal and light energy?
Answer: An example is a burning candle. The chemical energy in the wax is converted into thermal energy (heat) and light energy.
16. What is the principle of conservation of energy?
Answer: The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or converted from one form to another.
17. How does a pendulum demonstrate energy transfer?
Answer: A pendulum demonstrates energy transfer between gravitational potential energy and kinetic energy. At its highest point, it has maximum potential energy, which converts to kinetic energy as it swings down.
18. What is the role of friction in energy transfer?
Answer: Friction converts kinetic energy into thermal energy, often resulting in a loss of useful energy from a system.
19. How does energy transfer in an electric circuit?
Answer: In an electric circuit, energy is transferred from a power source (like a battery) to electrical devices (like bulbs or motors) through the movement of electric charges.
20. What is an energy transformation?
Answer: An energy transformation is the process of changing energy from one form to another, such as converting chemical energy in food to kinetic energy in muscles.
21. How does energy transfer in a car engine?
Answer: In a car engine, chemical energy from fuel is converted into thermal energy through combustion, which then transforms into kinetic energy to move the car.
22. What is the efficiency of energy transfer?
Answer: Efficiency is the ratio of useful energy output to the total energy input, expressed as a percentage. It indicates how effectively energy is converted or transferred.
23. What is an example of energy transfer in a roller coaster?
Answer: On a roller coaster, energy transfers between gravitational potential energy (at the peaks) and kinetic energy (during the drops and loops).
24. How does the law of conservation of energy apply to closed systems?
Answer: In closed systems, the total energy remains constant over time. Energy may change forms or transfer between objects, but the total amount does not change.
25. What is an example of energy transfer in a wind turbine?
Answer: In a wind turbine, kinetic energy from the wind is converted into mechanical energy as the blades turn, which is then transformed into electrical energy by a generator.
26. How does thermal energy transfer in conduction?
Answer: In conduction, thermal energy transfers through direct contact between particles, with energy moving from hotter to cooler regions.
27. How does thermal energy transfer in convection?
Answer: In convection, thermal energy transfers through the movement of fluids (liquids or gases), where warmer, less dense regions rise and cooler, denser regions sink.
28. How does thermal energy transfer in radiation?
Answer: In radiation, thermal energy transfers through electromagnetic waves, such as infrared radiation, without needing a medium.
29. What is an example of energy transfer in a hydroelectric power plant?
Answer: In a hydroelectric power plant, gravitational potential energy of water stored in a reservoir is converted into kinetic energy as it flows downhill, which then turns turbines to generate electrical energy.
30. How does energy transfer in photosynthesis?
Answer: In photosynthesis, light energy from the sun is converted into chemical energy stored in glucose molecules by plants.
31. What is an example of energy transfer in a battery-powered device?
Answer: In a battery-powered device, chemical energy stored in the battery is converted into electrical energy, which powers the device’s functions.
32. How does energy transfer in a microwave oven?
Answer: In a microwave oven, electrical energy is converted into microwave radiation, which transfers thermal energy to heat food.
33. What is an example of energy transfer in a solar panel?
Answer: In a solar panel, light energy from the sun is converted into electrical energy through the photovoltaic effect.
34. How does energy transfer in a refrigerator?
Answer: In a refrigerator, electrical energy is used to power a compressor, which transfers thermal energy from inside the fridge to the outside, keeping the interior cool.
35. What is an example of energy transfer in a flashlight?
Answer: In a flashlight, chemical energy in the batteries is converted into electrical energy, which is then transformed into light energy by the bulb.
36. How does energy transfer in a pendulum clock?
Answer: In a pendulum clock, gravitational potential energy is converted into kinetic energy as the pendulum swings, and this motion is used to keep time.
37. What is an example of energy transfer in a plant growing?
Answer: In a growing plant, light energy from the sun is converted into chemical energy through photosynthesis, providing the energy needed for growth and development.
38. How does energy transfer in an electric heater?
Answer: In an electric heater, electrical energy is converted into thermal energy, which is then radiated or convected to heat the surrounding space.
39. What is an example of energy transfer in a muscle contraction?
Answer: In muscle contraction, chemical energy stored in ATP molecules is converted into kinetic energy, enabling movement.
40. How does energy transfer in a combustion engine?
Answer: In a combustion engine, chemical energy in fuel is converted into thermal energy through combustion, and this thermal energy is then converted into kinetic energy to power the engine.
41. What is an example of energy transfer in a windmill?
Answer: In a windmill, kinetic energy from the wind is converted into mechanical energy to grind grain or pump water.
42. How does energy transfer in a hydrothermal vent?
Answer: In a hydrothermal vent, thermal energy from the Earth’s interior is transferred to water, creating hot, mineral-rich fluids that support unique ecosystems.
43. What is an example of energy transfer in a radio?
Answer: In a radio, electrical energy is converted into electromagnetic waves (radio waves), which are then converted back into electrical energy and finally into sound energy.
44. How does energy transfer in a geothermal power plant?
Answer: In a geothermal power plant, thermal energy from the Earth’s interior is converted into mechanical energy by turbines, which is then transformed into electrical energy.
45. What is an example of energy transfer in an incandescent light bulb?
Answer: In an incandescent light bulb, electrical energy is converted into thermal energy, which then produces light energy.
46. How does energy transfer in a nuclear power plant?
Answer: In a nuclear power plant, nuclear energy from fission reactions is converted into thermal energy, which generates steam to drive turbines, producing electrical energy.
47. What is an example of energy transfer in an electric motor?
Answer: In an electric motor, electrical energy is converted into mechanical energy to perform work, such as turning a fan blade.
48. How does energy transfer in a chemical reaction?
Answer: In a chemical reaction, chemical energy stored in bonds is converted into other forms of energy, such as thermal, light, or electrical energy, depending on the reaction.
49. What is an example of energy transfer in a bicycle?
Answer: In a bicycle, chemical energy from the rider’s muscles is converted into kinetic energy to move the bike, with some energy lost as thermal energy due to friction.
50. How does energy transfer in a wind-up toy?
Answer: In a wind-up toy, elastic potential energy stored in a spring is converted into kinetic energy, causing the toy to move.