Lesson 4.2 - Heat Transfer in Nature

You have learned how convection transfers heat in liquids.  This is how heat is transferred in lakes and oceans.  Is heat transferred in the atmosphere in the same way? 

Read Investigation 5C Part 2: Observe Convection in Air on page 93 in your textbook. Then, answer these questions.

Question 1. Write a prediction for Part 2: Observe Convection in Air of this investigation.

Question 2. Explain how convection currents in gases transfer heat.

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Write a prediction for Part 2: Observe Convection in Air of this investigation. 

The smoke will be drawn down into the cold chimney and come up the hot chimney.

Question 2. Explain how convection currents in gases transfer heat.

Convection currents in gases transfer heat in the same fashion as convection currents in liquids. 

The heated gas is less dense than the colder gas.  It rises and is replaced by the colder, more dense gas.  The heat is transferred throughout the gas by the continual heating of the gas at one location and the heated gas being replaced by colder gas.  This movement is called convection currents.

Put another way, convection currents transfer heat by moving heated gas upwards and replacing it with cold gas that is then heated.  The cycle continues and the gas moves in a circular pattern.

In this investigation, the convection currents are not circular because the tubes are open to the atmosphere.  The convection current would be more visible as a circular pattern if the tubes at the top were connected, but this would make it impossible to get the smoke into the apparatus. 


Go to the next page to continue Lesson 4.