What is a conductor?
National Science Education Standards:
Content Standard A: Science As Inquiry
Content Standard D: Physical Science - Light, heat, electricity and magnetism
These activities help students experience and understand how a conductor
carries heat energy.
(BACKGROUND INFORMATION)
What do we already know about conductors?
- Heat energy conduction occurs when heat energy moves from a hotter to a cooler item.
- Heat energy always travels from a hotter to a cooler material.
- Not all solids are good conductors of heat.
- Poor heat conductors are called insulators.
Activity One - Act it Out!
a bag of similar items such as paper clips, marbles, or any small item
that fits inside the bag
- Before the simulation: Fill a bag with similar items such as paper clips, marbles
or any small item that fits inside the bag. Include enough items for about 1/2 of
the students involved in the simulation.
- Explain that you will be directing the students to "act" out the movement of heat
energy by playing a modified version of the game "hot potato." Discuss how this is a
"simulation" of how heat energy is conducted through a material.
- Ask the students to line up in a single file.
- The teacher or adult will be the "source"” of the heat energy. Hand the bag of "heat energy"
to the first student. The "items" in the bag represent heat energy.
- Instruct the first student to take out one item and then quickly pass the bag to the next student.
- Each student should take out one item and then pass the bag to the next student until the "heat energy" runs out.
- Discuss how this activity simulates how heat energy travels from one item to another. Why is some of the heat energy lost?
Extension:
How could you change this game to show how heat energy travels faster through some materials
and slower through other materials?
Activity Two - It's Conduction
Per Group: hot water, heat-proof container, metal object (spoon), wooden object
(craft stick), plastic object (plastic fork)
- Ask students, "Have any of you ever helped cook anything?" Question students to see who
might have helped stir something hot as it cooked on the stove. Ask, "Was the spoon handle made of
plastic or metal?" The answer will probably be "plastic."
- Ask students to explain why plastic is often used for spoon handles. (Metal handles are good
conductors of heat energy and they get hot and might burn their hands.)
- Refer back to the first activity that simulated the movement of heat energy. Review the idea that
heat energy moves from warmer objects to cooler objects through conduction. Some examples would be
from a burner to a metal pan. This is also what happens to ice when you put it in a warmer liquid.
The ice does not LOSE its cold, it gains heat energy and even can melt.
- Place the plastic, wooden, and metal objects in an insulating cup.
- Ask the students, "What do you think will happen to each of these if I fill the cup with hot water?" Allow time for discussion, and then ask, "If you think the water will heat them,
tell me why. Which utensil do you think will get the hottest?"
- After students have shared their answers, pour the hot water into the cup. Have one or two
students carefully touch each object and rate them from coolest to warmest. Discuss the results
with the class.
- Discuss the following situations with the students.
Don is sick. He has a fever. Why did his mom put the cool cloth on his head?
Mark has hot tea. What will happen to his hands?
It is the day of the big fish fry. Megan forgot the pot holder. What will happen to her hands if she
picks up the pan?
The Sun has been shining all day. The lizard climbs on the rock to get warm. Tell why.
- Review the concept of conduction and conductor with students. Be sure that students understand
that heat energy travels from a hotter to colder item and that metals are good conductors of heat.
Wood, plastic, and glass are called insulators because they do not pass along heat well.
Extension:
Have students collect pictures of examples of conduction.
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