Bill Nye: Heat
Name: ________________ Hr.: __
Date: __________ Due: ________
Bill Nye the Science Guy shows you that the science of heat is hot!
Snow cones, flowers, hot dogs, people — everything is made of molecules. No matter what
phase they’re in, solid, liquid, or gas, molecules are always moving, even if just a little bit. The
speed of the molecules depends on their temperature. Cold things have slow-moving
molecules, while hot things have fast-moving molecules. In fact, temperature is really a
measurement of molecule speed. For a cold thing to get warm, its molecules have to speed
up.
Heat moves in three different ways — conduction, convection, and radiation. Conduction is
the flow of heat between two solid objects that are touching. Heat conducts from your warm
fingertips into a cold can of soda. Convection is the transfer of heat with a liquid or gas. A hot
bath feels warm all over not just where you’re sitting. Convection also happens naturally. When
air gets warmed by a hot burner, it’s molecules speed up and spread out. Then, cold air
molecules squeeze the warm spread-out molecules up. That’s why people say hot air rises. It’s
natural convection. Radiation is when heat beams or radiates from a warm object to cold
surroundings. Sit in front of a window at night. Hold your hand up with your palm facing the
window, then twist your wrist so your palm faces inside. You’ll feel the heat radiate from your
hand into the dark outside.
Did You Know That?
The average temperature on the moon is only -180 degrees Celsius (-292 degrees
Fahrenheit)?
Absolute Zero is the temperature where no molecules move?
Crocus flowers can sense temperature changes of half a degree Celsius (0.9 degrees
Fahrenheit)?
Questions:
1. Heat is ______________________so heat can do work.
2. What are the three ways in which heat moves?
a. ________________________________________
b. ________________________________________
c. ________________________________________
3. Which type of heat movement are the following examples of:
a. heat from our sun: __________________________
b. a warm tropical breeze: __________________________
c. a metal spoon in hot soup: _________________________
4. Anything that has ________________________ has heat.
5. Compare the movement in molecules in hot thing to the movement of molecules in cold
things. __________________________________________________________________
6. The transfer of heat by currents through a fluid (liquid or gas) is called
___________________________________________.
7. In natural convection, warm gases or liquids ______________________, while cool fluids
___________________________.
8. Heat can travel through a vacuum (empty space) only through the type of movement called
____________________________. The other two types of movements HAVE to have
molecules.
9. Brownies cook in the metal pan primarily through the movement of heat called
_______________________________. They cook in the glass pan primarily through
_________________________________,
10. When warm air rises from a toaster, that’s _________________________________,
11. What two units are used to measure heat? _____________________________________
12. What has to happen for heat to transfer? (Except sometimes with radiation.)
________________________________________________________________________
________________________________________________________________________
13. Which type of heat transfer will most affect the movement of your hot air balloon?
___________________________________________
14. Explain your answer to number 13.
________________________________________________________________________
________________________________________________________________________