Lesson 2.3 - Heat Transfer

Early scientists knew that heat somehow moved from one object to another.  The caloric theory of heat explained transfer as the caloric fluid flowing from one object to another.  Today, many people still think that cold can flow from one object to another.  "The cold from the ice cube flows into my hand" is a common misconception.  Do you think the cold from an ice cube flows into your hand?

Heat is transferred from hot objects to cold objects.  The old theory of caloric still seems to influence the way people talk about heat transfer; they say heat flows, implying it is some kind of fluid when it is not.  Even the textbook uses the words "heat flows".  This course will use the correct term: "Heat is transferred." 

Read Forms of Heat Transfer in Figure 5.8 and Science Myths on page 88 in your textbook

Question 1. Does heat move from cold objects to hot objects or from hot objects to cold objects?

Question 2. When does heat transfer stop?

Question 3. What do you predict you would feel if you were holding the metal bar at the green coloured end?

Question 4. What was the aether?  Why was the aether needed?

 

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Does heat move from cold objects to hot objects or from hot objects to cold objects? 

Heat is travels from hot objects to cold objects.

Question 2. When does heat transfer stop?

Heat transfer stops when the temperature of the two objects is the same.

Question 3. What do you predict you would feel if you were holding the metal bar at the green coloured end?

You should have predicted that the metal bar would start to feel warm as heat is transferred from the flame to the first metal rod and then to the second metal rod that you are holding.

Question 4. What was the aether?  Why was the aether needed?

The aether was a low density solid that space was made up of.  Scientists needed aether to explain how waves travelled through space.  They could not imagine how waves could move through empty space.

 


Now, do Assignment 5B.   Page forward to access the computer-scored assignment.