Basics
What property tells us how fast the particles are moving?
Temperature
What is heat transfer through direct contact called?
Conduction
Compared with cool air, is warm air more dense or less dense?
Less dense.
Particles are faster, more spread out.
What kind of material slows heat transfer?
Insulator
What happens when two objects reach the same temperature?
There is no heat to be transferred. They are at thermal equilibrium.
What is the total energy of the moving particles in a substance?
Thermal Energy / Heat
What heat transfer method can move energy through empty space?
Radiation
What happens to warm fluid as it becomes less dense?
It rises.
Is a metal spoon usually a conductor or an insulator?
Conductor
What term describes objects at the same temperature with no net heat transfer?
Thermal Equilibrium
How is the average particle motion different from the total energy of all particles?
Temperature measures average particle motion(speed); thermal energy is the total energy of the particles in a substance.
Give one example of conduction in everyday life.
*Answers will vary*
What is a convection current?
A convection current is the movement of warmer and cooler fluid as their temperature and densities differ.
Why are pot handles often made from plastic or another insulating material?
The handle slows heat transfer, making it safer to hold.
Which way does heat flow between objects at different temperatures?
Heat flows from the warmer object to the cooler object.
What may happen to a substance’s temperature when it gains thermal energy?
It's temperature may rise.
How does radiation transfer energy without direct contact?
Radiation carries energy through electromagnetic waves and does not require contact or matter.
Describe how a convection current forms in a pot of heated water.
Water near the bottom warms, becomes less dense, and rises. Cooler, denser water sinks, creating a moving cycle.
How can an insulator help keep a cold drink cool?
It slows heat transfer from the warmer surroundings into the drink.
A hot object is placed in cool water. Which object loses thermal energy, and which gains it?
The hot object loses thermal energy, and the cool water gains it.
A warm object and a cool object touch. What happens to their temperatures over time, and why?
The warm object loses thermal energy and the cool object gains it. Their temperatures move toward the same value.
A person feels warmth from a campfire without touching it. Name the transfer method and explain how energy reaches the person.
Radiation. Energy travels from the fire through electromagnetic waves to the person.
Explain how temperature and density differences create convection currents in air.
Warm air expands and becomes less dense, so it rises. Cooler, denser air sinks, creating a circulating current.
Compare how a metal spoon and a wooden spoon transfer thermal energy when placed in hot soup.
Metal conducts thermal energy more quickly than wood. The metal spoon warms faster, while the wooden spoon acts more like an insulator.
A metal block and a cup of water begin at different temperatures. Describe how they exchange heat and when they reach thermal equilibrium.
Heat flows from the warmer substance to the cooler one. They reach thermal equilibrium when they have the same temperature and there is no net heat transfer.