Heat & Thermal Energy
What is the energy that moves from a hotter object to a colder object?
Heat
What type of heat transfer happens through direct contact?
Conduction
Which type of heat transfer happens in liquids and gases?
Convection
Which type of heat transfer does NOT need matter or contact?
Radiation
What happens to most materials when they are heated?
They expand
What do we call the energy stored in an object that relates to its temperature?
Thermal energy
Which state of matter conducts heat best?
Solids
What happens to warm fluid in convection?
It rises.
How does radiation transfer heat?
Through energy waves
What happens to particles when a material cools?
They move slower and get closer together
In what direction does heat always flow on its own?
From hot to cold
Why do metals conduct heat better than wood or plastic?
Their particles are packed tightly and transfer energy easily
Why does cool air sink during convection?
It is more dense.
What type of heat transfer allows the Sun to heat Earth?
Radiation
What is thermal contraction?
When a material shrinks as it cools
What causes heat to transfer between objects?
A difference in temperature
What happens to particles during conduction?
Fast-moving particles bump into slower particles and pass energy along
What is the circular movement of warm rising fluid and cool sinking fluid called?
Convection current
This form of energy allows heat to travel without particles touching or moving.
Electromagnetic waves or energy waves
Which state of matter expands the most when heated?
Gases
Why do hotter objects have more thermal energy at the particle level?
Their particles move faster
Why does a metal spoon feel hotter than a wooden spoon in hot soup?
Metal is a good conductor; wood is an insulator
Why are heaters placed near the floor and air conditioners near the ceiling?
Warm air rises and cool air sinks
Why is radiation different from conduction and convection?
It does not require particles to move or touch
Why do bridges have expansion joints?
To allow materials to expand and contract without cracking