Temperature, Thermal Energy, and Heat
What is the total energy of all the particles in an object called?
thermal energy
What is the process by which heat transfers from one particle of matter to another when the particles collide?
conduction
Suppose you want to know the amount of heat needed to raise the temperature of 2kg of copper by 10 degrees Celsius. What property of the copper do you need to know?
the specific heat of copper
Use the illustration on p. 53
Which statement is true?
D has twice the thermal energy as A.
What is the scale the U.S. uses?
Fahrenheit
The temperature scale used in most of the world.
Celsius Scale
A convection current is....
the circular motion of a fluid caused by the rising of fluid as it warms and the sinking of fluid as it cools.
Wool is a good insulator which means....
it does not transfer heat well.
What does a thermometer measure?
the average kinetic energy of the particles in an object.
What is the lowest temperature possible in Kelvins called?
absolute zero
How does heat flow when you place an ice cube in your hand?
Heat flows from my hand to the ice cube.
Identify each example of heat transfer as conduction, convection, or radiation:
Opening the windows in a hot room
a lizard basking in the sun
putting ice on a sprained ankle
convection, radiation, conduction
When they are hung, telephone lines are allowed to sag. Why?
The lines contract when they get cold. They need slack so they don't contract and snap.
Which statement describes the direction of heat flow?
Heat flows from a warmer object to a cooler object.
What is heat?
the transfer of thermal energy from warmer objects to cooler objects.
Use the illustration on p. 51
Compare the average motion of the particles in the three containers.
The average motion of articles is greater at higher temperatures. The average motion is the same for A and B, greater for C.
How can heat be transferred across empty space?
Radiation which uses waves that don't need matter.
Use the illustration on p. 52
Why are two panes of glass used in the window shown? (hint: air is an insulator)
Air is a good insulator; so the air between the window panes helps prevent heat transfer.
The specific heat of iron is 450 J/(kg*K). How much thermal energy must be transferred to 15 kg of iron to raise its temperature by 4.0 K?
27,000 J
The amount of energy required to raise the temperature of 1 kilogram of material by 1 kelvin is called what?
specific heat
Use the illustration on p. 51
Compare the total amount of thermal energy in containers A and B.
The thermal energy in B is twice the thermal energy in A. It has twice as many particles at the same temperature.
Suppose you try to heat your home using a fireplace in one of the rooms. Would a fan be helpful?
Yes, the fan could be used to move the warmed air toward the rest of the house.
Suppose you were out camping and the weather turned cold. How would you keep war? Explain, and tell whether conduction, radiation, or convection is involved with heat transfer.
Use a fire: radiation; the air would warm around the fire: convection
Warm up water in a pot for cocoa, when the warm water is put in the cup, it transfers through conduction to my hands.
Which of the following can be classified as a good conductor of thermal energy?
silver
thermal expansion