When watching a daytime circus in a large, darkcolored tent, you sense significant heat transfer from the tent. Explain why this occurs.

Compare the rate of heat conduction through a 13.0-cm-thick wall that has an area of 10.0m2 and a thermal conductivity twice that of glass wool with the rate of heat conduction through a window that is 0.750 cm thick and that has an area of 2.00m2, assuming the same temperature difference across each.

Find the net rate of heat transfer by radiation from a skier standing in the shade, given the following. She is completely clothed in white (head to foot, including a ski mask), the clothes have an emissivity of 0.200 and a surface temperature of 10.0C, the surroundings are at 15.0C, and her surface area is 1.60m2.

Putting a lid on a boiling pot greatly reduces the heat transfer necessary to keep it boiling. Explain why.

Suppose you walk into a sauna that has an ambient temperature of 50.0C. (a) Calculate the rate of heat transfer to you by radiation given your skin temperature is 37.0C, the emissivity of skin is 0.98, and the surface area of your body is 1.50m2. (b) If all other forms of heat transfer are balanced (the net heat transfer is zero), at what rate will your body temperature increase if your mass is 75.0 kg?

The “steam” above a freshly made cup of instant coffee is really water vapor droplets condensing after evaporating from the hot coffee. What is the final temperature of 250 g of hot coffee initially at 90.0C if 2.00 g evaporates from it? The coffee is in a Styrofoam clip, so other methods of heat transfer can be neglected.

On a hot dry day, evaporation from a lake has just enough heat transfer to balance the 1.00kW/m2 of incoming heat from the Sun. What mass of water evaporates in 1.00 h from each square meter? Explicitly show how you follow the steps in the Problem-Solving Strategies for the Effects of Heat Transfer.

When a cold alcohol thermometer is placed in a hot liquid, the column of alcohol goes down slightly before going up. Explain why.

Construct Your Own Problem Consider a person outdoors on a cold night. Construct a problem in which you calculate the rate of heat transfer from the person by all three heat transfer methods. Make the initial circumstances such that at rest the person will have a net heat transfer and then decide how much physical activity of a chosen type is necessary to balance the rate of heat transfer. Among the things to consider are the size of the person, type of clothing, initial metabolic rate, sky conditions, amount of water evaporated, and volume of air breathed. Of course, there are many other factors to consider and your instructor may wish to guide you in the assumptions made as well as the detail of analysis and method of presenting your results.