Matter and Molecular Motion

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

Objectives:

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

Strategy:

Introduction:
     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 
bag.)

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