What is potential energy?
Energy of position or condition / stored energy that hasn’t been used
Potential energy is related to the position of an object.
What is kinetic energy?
Energy of motion
Kinetic energy is the energy an object possesses due to its movement.
How do the height and mass of an object affect its gravitational potential energy?
Greater mass & height = more GPE
Gravitational potential energy increases with both mass and height.
What is the Law of Conservation of Energy?
Energy can be transferred or transformed, but it cannot be lost or destroyed
This law emphasizes that energy remains constant in a closed system.
How does a car’s efficiency relate to the kinetic energy of motion?
Only about 25% of energy is transformed into KE of motion
The remaining 75% is lost as thermal energy and sound.
What is thermal energy?
The internal energy of a substance due to the movement of particles within that substance
Thermal energy is related to the temperature of the substance.
How is thermal energy transferred?
Transfers from hotter objects → cooler objects
This transfer occurs until thermal equilibrium is reached.
What determines the amount of thermal energy that can be stored in an object?
- The mass of an object
- The material of an object
Different materials have varying capacities to store thermal energy.
Define insulator and give examples.
Materials that slow down energy transfer: Plastic, wood, foam, rubber, cloth
Insulators are used to reduce heat loss.
Define conductor and give examples.
Materials that let heat move through them: Metal, water, steel
Conductors are effective in transferring thermal energy.
Why do metals feel colder than plastics?
Metals are better conductors
They transfer heat away from the skin more efficiently than plastics.
What happens to the water temperature when hot and cold water are mixed?
- Equal volumes: average temperature
- More hot: warmer temperature
- More cold: cooler temperature
The final temperature is influenced by the proportions of hot and cold water.
How do faster vs. slower moving molecules in a liquid relate to temperature?
- Faster molecules = higher temperature
- Slower molecules = lower temperature
Temperature is a measure of the average kinetic energy of molecules.
What does it mean to absorb energy?
An object that takes in or soaks up energy
Example: A black cloth taking in sunlight and getting hot.
What does it mean to transmit energy?
The act of passing through an object
Example: Light going through a window.
What does it mean to reflect energy?
Light bouncing off an object
Example: A mirror reflecting your face.
Define conduction and give an example.
Heat transferred by touch between two objects: A metal spoon getting hot in soup
Conduction occurs through direct contact.
Define convection and give an example.
Heat transferred in liquids or gases: Boiling water
Convection involves the movement of fluid.
Define radiation and give an example.
Waves transfer heat without direct contact: Tanning (sun)
Radiation can occur through a vacuum.
How do solar ovens work?
Use sunlight as energy, absorb sunlight, trap heat inside
They cook food using the thermal energy provided by the sun.
What does more thermal energy in the atmosphere mean for weather events?
More thermal energy means hurricanes
Increased thermal energy can lead to more severe weather phenomena.
What is energy efficiency?
Using less energy to get the same outcome as using more energy
Efficiency is a measure of how well energy is utilized.
What is gravitational potential energy?
The energy stored in an object based on the height
It is calculated based on the object’s mass and height above the ground.
What is kinetic energy?
The energy an object has because it’s moving
Kinetic energy is dependent on the mass and velocity of the object.
