Convection, Conduction, and Radiation

1. Convection, Conduction, and Radiation

2. What is Heat Transfer??? • Heat transfer occur all of the throughout our everyday environment. We see it happening everyday but see it so much that we don’t even think about it while it is happening. • Like walking on the hot pavement in the summer time barefoot…. What happens to your feet?

3. Heat Transfer • Your feet get hot. • This is because heat transfers from things that are hot to things that are cool. • Heat transfers in three different ways in our environment.

4. Heat Transfer • There are three main different types of heat transfer: • Convection • Conduction • Radiation

5. What is Convection? • Convection is heat transfer that occurs in liquids and in gases.

6. How can I see convection? • Convection is slightly harder to see then the others. Have you ever been outside on a very hot day and have seen the "heat" bend light in the air, making swirlies in the air? • If you have ever watched a pot on the stove boil, then you are seeing convection occurring.   • What happens is that cold water or air sinks (because it is heavier then hot water or air) and the hot water or air rises.  As it rises it cools down and sinks.  This creates a circulation we call convection.

7. What is Conduction? • Conduction is what happens when heat is transferred between two bodies that are close or touching. • The better the conductor the more rapidly the heat will transfer.

9. Where can I see conduction in my life? • Pour hot water into a coffee cup and feel the heat conducting through the coffee cup. This is conduction. • You can also feel the cold when you have a glass of ice water and the cold comes through the glass.  

10. What is heat transfer Radiation? • This is when electromagnetic waves travel through space. When these waves come in contact with an object, they transfer the heat to the object.

11. Where can I see Radiation? • Sit by a sunny window.  Do you feel the warmth of the sun on your skin?  This is radiant heat or solar radiation. • You can also find this in toasters and electric ovens with heating elements.  The heat from the elements is radiant heat and this is what cooks the food.  An element on an electric stove does the same thing.