Heat Energy Review

What is convection?
The transfer of thermal energy by the movement of a liquid or gas
What is conduction?
The transfer of thermal energy from one substance to another through direct contact
What is radiation?
The transfer of heat energy by electromagnetic waves such as visible light and infrared waves
What are examples of Conduction, Convection and Radiation?
Conduction-when the end of the spoon gets warmer when the spoon is in the bowl of soup
Convection- when the pot of water boils on the stove
Radiation- when your body absorbs rays from the sun (your body feels warmer)
What happens to molecules when heated?
The molecules speed up
How does thermal expansion make a hot air balloon rise?
The energy of the molecules increases as the air is heated, causing them to expand outward. This causes the volume of the air to increase and its density to decrease. The less dense air inside the balloon rises above the more dense air around the balloon, causing it to rise up.
How are convection currents formed in either a gas or liquid?
As a gas or liquid is heated, its molecules move farther apart and it becomes less dense; as it becomes less dense, it rises; when it cools, it becomes less dense and sinks.
Why are thermal energy joints useful?
Thermal energy joints are gaps in the pavement that allow for expansion without jeopardizing the integrity of the structure.
What's a conductor
It's a substance that conducts thermal energy well.
What's an insulator?
It's a substance that doesn't conduct thermal energy well.
What are 3 examples of a conductor?
Silver, Aluminum and Steel
What are 3 examples of an insulator?
Wood, Fiberglass and Plastic
What is temperature?
It is a measure of the average kinetic energy of the particles in an object
What is thermal energy?
It is the total kinetic energy of the particles that make up a substance
What is heat?
It is the energy transferred between objects that are at different temperatures.
What direction does heat travel?
Heat travels from warmer to cooler areas
What happens when most items are heated and cooled?
Most items will expand when heated and contract when cooled.
What is the exception in the principle that substances contract when cooled?
Water expands when it freezes
Which of the following has the greatest temperature and the greatest thermal energy, a candle and an iceberg?
The candle has the greatest temperature because it has a higher average of kinetic energy, the iceberg has the greatest thermal energy because its particles are more packed together.