Lesson 5.2 - Cooling Technologies

You use many technologies to heat your home and cook your food.  You use technologies to keep the food cold in your refrigerator, frozen in the freezer, and cool in a plastic cooler.  All vehicles need some way to keep the engines cool.  Learn more about heat transfer technologies and how they work.

Read Getting Rid of the Heat on page 100 in your textbook. Then, answer the following.

Question 1. Why is it necessary to remove the heat from an engine?

Question 2. What is a radiator and what is it made from?

Question 3. How is the heat transferred from the motor to the radiator?         

Question 4. How is the heat transferred from the radiator to the air?  

Question 5. Why is a fan necessary in the cooling system?

Question 6. Air-cooled engines such as those on motorcycles and lawnmowers do not have radiators.  How are they able to get rid of the heat produced by the engines? 

 

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Why is it necessary to remove the heat from an engine?

Internal combustion engines produce a lot of heat.  If this heat is not removed, the engine will overheat and be damaged.

Question 2. What is a radiator and what material is it made from?

A radiator is device that is used to transfer large quantities of heat to the air.  Radiators are made of good conductors such as copper and aluminum.

Question 3. How is the heat transferred from the motor to the radiator?   

A liquid coolant is used to transfer heat from the motor to the radiator.  The liquid is heated inside the motor by conduction.  The hot coolant is pumped to the radiator where it transfers the heat to the radiator by conduction.  Cooled coolant is then pumped back to the motor.  

Question 4. How is the heat transferred from the radiator to the air? 

Heat is transferred from the radiator to the air by conduction.  The cool air passes through the fins of the radiator and the hot radiator transfers the heat to the air.  The radiator also radiates some heat as infrared radiation.

Question 5. Why is a fan necessary in the cooling system?

A fan is necessary to move air through the radiator when the vehicle is not moving.  When the vehicle is moving at high speed, the fan is not needed because plenty air moves through the radiator.

Question 6. Air-cooled engines such as those on motorcycles and lawnmowers do not have radiators.  How are they able to get rid of the heat produced by the engines? 

Air-cooled engines have fins on the outside of the engine.  These fins have a large surface area that, when in contact with cool air, transfer the heat to the air.  Most air-cooled engines have a fan to increase the quantity of cool air that moves over the engine.  (Lawnmowers do not travel very fast! Small airplanes with air-cooled engines do not have that problem!)  


Go to the next page to continue Lesson 5.