The air temperature in the room is 20°C. A student places an ice cube (0°C) in his hand. The student’s body temperature is 37°C. What is the correct direction of heat flow?

A. From the ice to the person, only
Incorrect. Heat travels from hotter to cooler.

B. From the person to the ice, only
Incorrect. Other heat transfer is happening.

C. From the person to the ice and the air, and from the air to the ice
Correct! You got it right.

D. From the ice to the person and air, and from the air to the person
Incorrect. Heat travels from hotter to cooler.

A 25g block of aluminum at 15°C is dropped into a cup of water measuring 5°C. Which of the following best describes the transfer of heat?

A. Both the aluminum and the water will adjust to the same temperature below 5°C.
Incorrect. Objects try to reach thermal equilibrium - a temperature that they reach that is between their beginning temperatures.

B. The water and the metal will adjust to the same temperature between 5°C and 15°C.
Correct! The aluminum and water will eventually be at the same temperature, between their starting temperatures.

C. The water will remain the same temperature, but the metal will cool to 5°C.
Incorrect. Objects try to reach thermal equilibrium - a temperature that they reach that is between their beginning temperatures.

D. Both the aluminum and the water will adjust to the same temperature above 15°C.
Incorrect. Objects try to reach thermal equilibrium - a temperature that they reach that is between their beginning temperatures.

In which of the following containers would the transfer of heat by CONVECTION be impossible by the substance?

A.
Incorrect. Convection can occur in liquids or gases.

B.
Incorrect. Convection can occur in liquids or gases.

C.
Incorrect. Convection can occur in liquids or gases.

D.
Correct! Convection does not occur in a solid.

A cold-blooded reptile basks on a warm rock in the sun. Its body is warmed by —

A. radiation
Incorrect. Radiation is just one of the ways.

B. conduction
Incorrect. Conduction is just one of the ways.

C. convection
Incorrect. Convection would not be heating the snake.

D. both A and B
Correct! Radiation from the sun and the snake touching the warm rock, would both transfer heat to the snake.