Matter and Molecular Motion

Susan Schwartz DeWitt Clinton Elementary School
6110 N. Fairfield Ave.
Chicago IL 60659
(773) 534-2025


This lesson is designed for Grade 4.
Students will be able to:
1. Define the three states of matter and some of their properties.
2. Demonstrate that air is matter and even though gases cannot always be
seen, they take up space.
3. Observe the effect of molecular motion (hot and cold).

Materials Needed:

Teacher Demonstrations:
Introduction: chalkboard, chalk, three jars - one with a solid(s) in it, one
filled with water, and one with nothing but air in it
Activity 7: two large clear containers, two small baby food jars with lids, hot
plate, sauce pan, food coloring, ice, tap water
Activity 8: ice, two small baby food jars, two large-mouthed clear jars, warm
and cold tap water, food coloring, two 6-inch squares of aluminum foil, two
rubber bands, and a pencil
Materials Needed for Each Student:
Activity 1: plastic fruit/vegetable bag
Activity 4: small-mouthed 20 ounce pop bottle, balloon
Activity 5: small-mouthed 20 ounce pop bottle, bottle cap, water
Materials Needed for Groups of Four Students:
Activity 2: 9 ounce clear plastic cup, 6 marbles, masking tape, water
Activity 3: large wide-mouthed jar or clear container, paper towels, 9 ounce
clear plastic cup
Activity 6: jar, water, food coloring


Define matter as anything that takes up space and has mass. Mass is the
amount of matter in something. All matter is made up of tiny particles.
Discuss the three states of matter: solid, liquid, and gas. Show students three
jars each containing an example of one form of matter. (Solid - blocks, liquid
- water, and gas - air). Ask the students how they know whether something is a
solid, liquid, or gas. List the students' responses on the board. Ask the
students how they know there is air in the jar that appears empty.

Activity 1: Demonstrate that air is matter and takes up space.
1.) Take an empty plastic fruit/vegetable bag. Open the top and move the
bag through the air. 2.) Close the top of the bag by twisting the opening and
holding it with your hand. 3.) Squeeze the bag with your other hand. 4.) Ask
the students to explain what happened. What is in the bag? (Air is in the

Activity 2: Observe that two pieces of matter cannot occupy the same space at
the same time.
1.) Take a clear plastic cup and fill it halfway up with water. 2.) Mark
the top of the water line with a piece of tape. 3.) Very carefully add 6
marbles to the water by tilting the cup and letting one marble at a time slide
down the inside to the bottom of the cup. Set the cup upright, and notice the
water level. What happened to the water level? Why? (The water level is
higher because two pieces of matter cannot occupy the same space at the same
time. The water is pushed out of the way by the marbles. The rise in the water
level is equal to the volume of the marbles.)

Activity 3: Demonstrate that even though gases cannot always be seen, they do
take up space.
1.) Fill a large container 1/2 full of water. 2.) Wad a paper towel(s)
into a ball and push it to the bottom of a 9 oz. cup. 3.) Turn the cup upside
down making sure the wadded up paper remains in the bottom of the jar. 4.) Hold
the cup upside down with its opening pointing down. Push the cup straight down
into the large container of water. DO NOT TILT the cup as you lift it out of
the water. 5.) Feel the paper and examine it. What happened? Why? (The cup
is filled with paper and air. The air prevents the water from entering the cup,
so the paper stays dry. Remember two pieces of matter cannot take up the same
space at the same time.)

Activity 4: To try to inflate a balloon inside a bottle.
1.) Hold the top of the balloon and push the bottom of the balloon inside
the bottle. 2.) Stretch the top of the balloon over the mouth of the bottle.
3.) Try to inflate the balloon by blowing into it. What happened? Why? (The
bottle is filled with air. Blowing into the balloon causes the air particles
(molecules) inside the bottle to move together, but only slightly. The air is
in the way of the balloon, preventing it from inflating. Remember two pieces of
matter cannot occupy the same space at the same time.) Try putting a hole in
the bottom of the bottle and then see if the balloon can be inflated inside the
bottle. Try different size bottles and holes.

Activity 5: Demonstrate that particles (molecules) move faster when heated.
1.) Remove the cap from a 20 oz. pop bottle and dip it in water. Place the
bottle cap upside down on the mouth of the bottle. 2.) Rub your hands together
until they are very warm. 3.) Place your hands around the bottle. DO NOT SQUEEZE the bottle. Wait about 20 or 30 seconds and observe what happens. (The
bottle cap should rise on one side and then fall back when excess gas escapes
from inside the bottle. Your warm hands heat up the gas inside the bottle
causing the particles to move faster and expand. The movement of the cap will
continue until the temperature inside the bottle equals the temperature outside
the bottle.) Try various size bottles and/or more hands on a bottle.

Activity 6: Observe the effect of molecular motion.
Put two drops of food coloring into a jar of water. What happens? Why?
(The food coloring forms colored streaks as it sinks to the bottom of the jar,
because the particles (molecules and atoms) that make up matter are constantly
moving. The moving water molecules are pushing and shoving the particles of
food coloring. Eventually, the colored particles will be evenly spread
throughout the water.)

Activity 7: Observe how water temperature effects molecular motion.
1.) Fill two clear containers with room temperature water. 2.) Fill one
small jar with ice water and one with heated water. Add blue food coloring to
the jar of ice water and red food coloring to the jar of hot water. Stir both
jars. 3.) Put the lids on both jars and place each jar on the bottom of the two
clear containers. 4.) Carefully take the lids off of the two jars. What
happens? Why? (The hot red water will flow to the top of the water in the
clear container and the cold blue water will flow to the bottom of the other
clear container. The hot water particles move faster and are farther apart than
the cold water particles which move slower and are closer together. Cold water
has greater density than hot water, so cold water sinks and hot water rises.)

Activity 8: Observe the downward flow of cold colored water through warmer
clear water and the upward flow of hot water through cold water.
1.) Place an ice cube in a small baby food jar. Fill the jar with water.
2.) Fill the large jar to within an inch of the top with warm tap water.
3.) Remove the ice from the small jar. Add and stir 6 or 7 drops of food
coloring to the ice water. 4.) Cover the mouth of the small jar with aluminum foil.
Secure the foil with a rubber band. 5.) With the point of a pencil, make a
small hole in the foil. 6.) Quickly turn the small jar upside down and hold it
so the hole is just beneath the surface of the warm water. 7.) Slowly and
gently tap the bottom of the small jar with your finger. What happened? Why?
(The cold colored water flows downward, because it is heavier than warm water.
When the small jar is tapped, the water comes out in spurts producing smoke-
like, colored rings in the water.) Repeat steps 1-4 with hot water. Place the
jar upright inside an empty large jar. Fill the large jar with cold water.
What happens? Why? (The hot water flows to the top of the large jar because it
is less dense than the cold water.) Try turning both of the small jars on their
sides. What happens? Why?

Performance Assessment: Ongoing assessment throughout activities based on the students' participation and responses. References: VanCleave, Janice. Chemistry for Every Kid. New York: John Wiley and Sons,
Inc., 1989

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