Heat, Conduction, and Radiation
Define insulator with 3 examples
A material that does not allow heat to move through 1) Glass 2) Rubber 3) Plastic
Convection
During the summer it's cooler in the basement of your home than the upstairs.
Explain how all 3 methods are involved in the following example: After turning on a lamp you put your hand over the bulb and feel heat.
Energy transfers via conduction through the wire and the heat radiates out from the light bulb in all directions. The air above the light bulb heat up and rises (convects).
Conduction
Eric the cat heats himself on a cold winter day by sitting on the hood of a warm engine.
Explain how the following situation occurs using conduction, convection, and radiation. A pot of water boils on a hot stove.
Heat conducts to the pan, water heats by conduction and heat from radiation.
On a hot summer day, should you close all of the blinds and curtains in your home or leave them open? Why?
Keep them closed because the heat from the sun will radiate inside making it warm.
Conduction
Packing cans of soda in a cooler full of ice will cause them to become very cold.
Radiation
Sunlight is absorbed by the Earth after it has made a 100,000,000 mile journey through space.
Convection
The best place to put a heater is at floor level.
In the evening snow falls on a cement sidewalk and on a blacktop playground. Which surface will melt the snow faster and why?
The blacktop because it conducts heat better.
Conduction
The handle of metal spatula gets hot while sitting in a hot skillet.
Define conduction with 3 examples
The process of transferring energy by direct contact 1) A pot sitting on a hot burner 2) Touching a metal spoon that is sitting in a pot of boiling water 3) Picking up a hot cup of coffee
Radiation
The reason black top is hot in the first place.
Conduction
The red alcohol in a thermometer rises when the bulb of it is put in boiling water.
Define convection with 3 examples
The transfer of heat through a fluid (liquid or gas) caused by molecular motion 1) When hot air rises 2) Boiling water 3) Hot air balloon
Define radiation with 3 examples
Transfer of heat energy through electromagnetic waves 1) Heat from a campfire 2) The sun on your skin 3) Heat from a lightbulb
Radiation
You sit in front of the fireplace and feel the warmth coming from it.
Conduction
Your feet burn when you walk barefoot on a black road on a hot summer day.
A cook uses an iron frying pan to cook a meal. After cooking, he places the hot frying pan on the counter. After a while, the frying pan, the counter, and the air in the room will be at the same temperature. Why?
a. Because thermal energy will be transferred from the frying pan to the counter and from the frying pan to the air b. Because coldness will be transferred from the counter to the frying pan and from the air to the frying pan c. Because thermal energy will be transferred from the frying pan to the counter and from the frying pan to the air, and coldness will be transferred from the counter to the frying pan and from the air to the frying pan d. Because thermal energy will be transferred from the frying pan to the air,but thermal energy will not be transferred from the frying pan to the counter.
Which of the following has thermal energy?
a. Both a piece of metal that feels hot and a piece of metal that feels cold b. A piece of metal that feels hot but not a piece of metal that feels cold c. A piece of metal that feels cold but not a piece of metal that feels hot d. Neither a piece of metal that feels hot nor a piece of metal that feels cold
A boy has two identical cookies except that one cookie is hot, and the other cookie is the same temperature as the air in the room. He places both cookies on a cold plate. Which cookie will transfer more thermal energy to the plate and why?
a. The hot cookie will transfer more thermal energy because only hot objects transfer thermal energy. b. The hot cookie will transfer more thermal energy because the temperature difference between the hot cookie and the cold plate is bigger than the temperature difference between the cookie at room temperature and the cold plate. c. Both cookies transfer the same amount of thermal energy because they are both the same size, and the amount of thermal energy transferred depends on size but not on temperature. d. Neither cookie transfers thermal energy to the plate; instead, coldness is transferred from the plate to the cookies.
The temperature of a plastic cup is 70˚F. It is filled with water that is 40˚F. Which of the following describes how thermal energy is transferred?
a. Thermal energy is transferred from the water to the cup until they are both at 45˚F. b. Thermal energy is transferred from the cup to the water until they are both at 45˚F. c. Thermal energy is transferred from the cup to the water until the cup is 60˚F and the water is 50˚F. d. No thermal energy is transferred between the water to the cup so the cup will stay at 70˚F and the water will stay at 40˚F.
A student is holding a cold piece of metal in her hand. While she is holding the piece of metal, her hand gets colder. Does the piece of metal get warmer? Why or why not?
a. Yes, the piece of metal will get warmer because some cold is transferred from the metal to the student's hand. b. Yes, the piece of metal will get warmer because some thermal energy is transferred from the student's hand to the metal. c. No, the piece of metal will stay at the same temperature because an equal amount of thermal energy and coldness is exchanged between the student's hand and the metal. d. No, the piece of metal will stay at the same temperature because neither thermal energy nor coldness is transferred between the student's hand and the metal.
Which of the following is the worst conductor heat in this group?
a. air b. a vacuum c. plastic d. aluminum
Which of the following is the best conductor of heat?
a. air b. plastic c. water d. aluminum
How does the heat of the sun reach the earth's atmosphere
a. by conduction, convection and radiation b. by convection and radiation c. by conduction and convection d. by radiation only
Which of the following is NOT a method of heat transfer?
a. conduction b. convection c. condensation d. radiation
The process by which a pot of water on your electric stove starts to heat is
a. conduction b. convection c. radiation d. evaporation
The main method of heat transfer that causes a pot of water to boil is
a. conduction b. convection c. radiation d. insulation
The type of heat transfer can occur in a vacuum
a. conduction b. convection c. radiation d. insulation
If a thermos bottle was not "silvered" on its surfaces, it would be able to transfer heat by
a. conduction. b. radiation. c. convection. d. it would not be able to transfer heat at all.
The fact that, in general, liquids and gases expand when heated gives rises to
a. convection currents in fluids due to changing masses. b. convection currents in fluids due to changing densities. c. heat transfer by conduction. d. convection currents in fluids due to constant temperatures.
Heat transfer by conduction
a. is not possible from human being to their environment b. does not occur from light bulbs they are too bright. c. requires some sort of material to facilitate the heat transfer d. none of the above.
Heat transfer by radiation
a. is not possible from human beings to their environment. b. does not occur from light bulbs they are too bright. c. does not require any material between the radiator and the object receiving the radiation. d. none of the above.
The transfer of heat by convection will only occur in
a. metals, like gold or copper b. fluids, liquids or gases c. space, a vacuum d. small areas
Is energy being transferred in either of these situations? Consider the following situations:
i. Situation 1: A person touches a cold piece of metal. ii. Situation 2: A lamp shines light on a table. b. Energy is transferred in both situations. c. Energy is NOT transferred in either situation. d. Energy is transferred when a person touches a cold piece of metal, but energy is NOT transferred when a lamp shines light on a table. e. Energy is transferred when a lamp shines light on a table, but energy is NOT transferred when a person touches a cold piece of metal.
