Matter and heat
Grade Level: 1-3

Overview Young students have a difficult time conceptualizing many science concepts. They have a need to actively participate in learning, and even then may not comprehend why an event occurs. One such concept is the motion of molecules and the relationship of heat to states of matter.

Purpose To involve students in demonstrating the relationship between molecules and states of matter.

Objectives Students will be able to:

i. Predict that heating a substance will cause it to expand (get big), and cooling it will cause it to contract (shrink).
ii. Distinguish between solids, liquids, and gases.
iii. List examples of solids, liquids, and gases in their world.

iv. Explain the states of matter using molecular properties.

Resources/Materials
Paper punch
Small microscope or hand lens
A flask
Two bowls
Ice cubes and hot water

Balloons

Activities and Procedures
1. Introduction
-Discuss the concept that everything is made up of molecules. Show them a "mosaic picture" made up ahead of time from paper punches. This is a simplified exaggeration of something being made up of little things.

-Encourage them to look at several items with hand-held microscopes (30x). Cloth, colors on covers of workbooks, and leaves are good for viewing small parts that are invisible to the eye. Emphasize that they are still not seeing molecules, which are even tinier than each dot they see on the book cover.

2. Small group experiment Materials needed (for each group)- small flask or bottle, two bowls, balloon, ice, hot water(from a coffee pot is best, but you need to supervise this as it will burn)

Procedure-
-Put the balloon on the bottle. Have the children establish that the bottle has air in it and that the air molecules inside cannot get out of the bottle when the balloon is on it.
-Ask the children if they think the balloon will change if we put the bottle in hot water. Encourage idea exchange.
-Get 3 cups of hot water. Put it in a bowl and put the bottle in the bowl also. Let each child feel the bottle as it warms up. Have them observe the balloon.
-Ask the children if they think the balloon will change if we move the bottle to cold water. Encourage idea exchange.
-Get 2 cups of cold water and 4-6 ice cubes to put in the other bowl. Put the bottle in the bowl, and again let the children feel the bottle as it cools off. Have them observe the balloon.
-Let the children move the bottle back and forth as time allows, and encourage predicting what will happen when they do.

-Ask for possible explanations and accept them all as something to consider.

3. Whole class activity

-Put a string circle on the floor, in the middle of an open area (This should be large enough for all the children to stand in without crowding.)
-Have the whole class stand up and explain that they are now going to "become" molecules. Explain that warm molecules are very active and spread out away from other molecules. Have them spread out and "bounce." Explain that molecules which bounce all over are a gas.
-Ask if they've ever seen children "huddle" on the playground on a very cold day. Molecules do the same thing. They slow down and move closer together when they are cold. Ask the children to come into the circle and to huddle close together. They should then "freeze". When molecules get cold enough they freeze, although that does not mean they are totally without motion, even as the children will not be totally without motion. Ask if they can think of an example of something "frozen" (ice). Explain that this is a solid.
-Molecules are sometimes in between. We call this state liquid. They spread out a little bit, but they stay inside their container. Have the children bounce slightly and push apart but stay inside the circle. Ask for an example of a liquid (water).

-Have them get back in their huddle, very still and "cold." Then have them "warm up" gradually, staying in the circle. Then have them warm up more, and explain that they can now float up over the string because they are a "gas." Ask what would happen if they were even "hotter" (they would spread out even more). -Now you are ready for some exercise. Using the cues Hot, Warm, Cold, etc, or Solid, Liquid, Gas, have them show by their actions what the molecules would do in that state.

4. Discussion

-Now discuss the experiment from earlier in the lesson. Ask for ideas on what the molecules were doing inside the balloon.

NOTE An additional adult or two is very helpful for the small group experiment. Another management technique could be to allow students to make mosaic pictures of their own while the teacher works with one small group at a time.

Tying it all together This provides a good basis of understanding for further studies of matter. Part/whole relationships in many areas can be related back to this. Students could be asked to begin a chart of solids, liquids, and gases using words or pictures. Assessment Find out from the students if there is any other substance that can behave like water. Which takes longer to accomplish: Changing water to ice or changing water to vapor?

Suggestions/Modifications

  • If the class size is very large you may want to demonstrate the molecule activity with a few students in the front of the room, until all students understand how it works.
  • You may extend the lesson to include the principal characteristics of atoms and even more with protons, electrons, and neutrons.
  • You may substitute some of the materials in this lesson as long as the outcomes are the same.

Author(s) DEBORAH HERNDON, IXL ELEMENTARY SCHOOL, ARKANSAS CITY, KS

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