Conduction, Convection, and Radiation

Subject Area

Thermal Physics

Age or Grade

9^th grade, Active Physics Curriculum

Estimated Length

50 minutes

Prerequisite knowledge/skills

Existence of molecules, concept of energy.

Description of New Content

Relationship between temperature and molecular motion.

Transmission of heat through conduction, convection, and radiation

Goals

Students will understand three ways of heat transfer.

Materials Needed

A small and a large clear glass beaker, food coloring, water

Two-chimney convection box , incense stick.

Wax and a spoon, and a candle.

Heat lamp

Procedure

Opener: Discussion of molecules and their motion.

Development:

- Demonstrate convection by showing how hot water rises in the container full of cold water.

- Show how the same holds for the hot air using the two-chimney box.

-Demonstrate conduction by showing how the hardened wax stuck to one end of a spoon melts and falls off when a flame is applied to the other end of the spoon.

-Demonstrate radiation with a heat lamp.

Closure:

Students are invited to test the theory by suggestion variation on the set up (for example, our students asked us to show what happens if you put a small beaker of cold water in a beaker of cold water and were amazed to see that the cold water didn't rise.)

Evaluation

Students created posters depicting radiation, convection, and conduction.

Extensions

"Molecules in Motion", a video by Ignite Learning on molecular motion, heat, and temperature scales.

References

http://www.physics.auburn.edu/demo/therm/4b/4b20_20.htm