Energy, Heat, and Temperature Study Guide

What is energy?
Energy is the ability to cause change.

What is the law of conservation of energy?
Energy can be transferred or transformed, but it cannot be created or destroyed.

According to the law of conservation of energy, what should happen to the total amount of energy before and after an event?
The total amount of energy before something happens must be equal to the amount afterward.

The total energy amount doesn’t change.

A moving car smashes into a parked car and as a result, the parked car began to move.

Is this an example of energy transfer or energy transformation?

Energy transfer.

The kinetic energy of the of moving car was transferred to the parked car.

You start a camp fire by lighting couple of fire wood.

Is this an example of energy transfer or energy transformation?

Energy transformation.

Chemical potential energy of the fire wood transformed into thermal energy, sound, and light.

What is thermal energy or heat?
Thermal energy or heat is an energy due to random motion of atoms and molecules.

Thermal energy or heat always flows from…
Thermal energy or heat always flows from object with higher temperature to object with lower temperature.

What is temperature?
Temperature is the average kinetic energy of particles in an object.

How is heat (or thermal energy) different from temperature?
Heat is energy and temperature is not energy.

To raise temperature of an object, what must happen?
You must add energy.

Temperature of a cup of water dropped by 10C.

What does this indicate about the water?

The cup of water lost thermal energy to its surrounding.

When you leave your home, you body feels cold.

What does this mean?

You body feels cold because you are losing thermal energy or heat to the surrounding air.

What are three possible ways heat is transferred?
1. Conduction
2. Convection
3. Radiation

What causes the transfer of heat?
Difference in temperature

What is conduction of energy?
Conduction is the transfer of energy from a warmer object to a cooler object through direct contact.

What is a conductor of energy?
Conductor is an object that transfers energy quickly.

What is an insulator of energy?
Insulator is a poor conductor. It transfer energy slowly.

What is convection of energy?
During convection, energy is transferred by movement of particles in gases and liquids.

What causes gases and liquids to rise when they are heated?
When gases and liquids are heated, they become less dense and pushed upward by gases and liquids that are more dense.

What is radiation?
Radiation is energy that travels as electromagnetic waves.

What happens when an object absorbs radiation?
When an object absorbs radiation, its temperature increases due to increased thermal energy or heat.

The warmth you feel when you hold a hot-water bottle.
Example of conduction

The fact that it’s hotter upstairs in a house than downstairs, due to heat rising.
Example of convection

Feeling the heat of a campfire from a distance.
Example of radiation

A Styrofoam cooler slowly gaining heat from the surroundings on a hot day.
Example of conduction

The warmth you feel when you place your hands above a campfire.
Example of convection

The heat we can feel on Earth from the Sun.
Example of radiation