DOES GAS TAKE UP SPACE???

MATERIALS

Balloon
Paper towel
Drinking glass
Sink of water
Optional: Styrofoam peanut

PROCEDURE

1. Have child blow up a balloon. Ask, “What is inside this balloon?” (carbon dioxide gas molecules.) “Does the gas take up space?” (yes) “Why can’t you see the gas?” “Where does the gas go when the balloon pops?”
2. Now, stuff a paper towel into the bottom of a drinking glass so that it will not fall out when the glass is inverted.
3. Fill your kitchen sink full of water.
4. Ask, “Do you think this paper towel will get wet if we plunge this glass upside down into the sink of water?”
5. Hold the glass upside down and quickly plunge it into the water.
6. Count to ten while holding the glass underwater.
7. SLOWLY lift the glass up and out of the water. Be sure to hold the glass straight up and down.
8. Observe. What happened to the paper towel?
9. May also do this with a piece of Styrofoam. Place the Styrofoam in the water. Place your glass upside down over the Styrofoam and push straight down into the water. What happened?

EXPLANATION

Air (gas) molecules take up space. Therefore, water could not get into the glass. The paper towel, and the Styrofoam peanut, remained dry.

FRICTION THROUGH WATER

MATERIALS

Wide-mouthed see-through jar, or empty tennis ball can
Clay
Water

PROCEDURE

1. Add water to your container until it is almost full.
2. Take a small amount of clay and roll it into two small balls.
3. Take one of the balls and flatten it like a small pancake. Leave the other piece round and smooth.
4. Hold both pieces of clay just above the surface of the water. Ask, “Which piece of clay do you think will drop the fastest?”
5. Now drop both pieces of clay through the water at the same time. Observe. Discuss. What role did friction play with the different speeds of the clay?


EXPLANATION

Friction is the resistance of motion on the surface of a body. The more surface, the more friction, the more resistance to motion. Fish and boats are streamlined to reduce their surface so they can speed through water more easily.

ACID INDICATOR

MATERIALS

Bromthymol blue (BTB) (available in supply catalogs)
A cup (a glass, or even a test tube)
Drinking straw

PROCEDURE

1. Add 1-2 drops BTB to 15 ml of water.
2. Using the straw, blow into the BTB solution.
3. Observe.

EXPLANATION

BTB is an indicator for acid. Carbon dioxide, when mixed with water, forms a weak acid. When acid is present, the blue BTB will turn yellow. When you blow out, you are blowing out carbon dioxide. You should see the solution turn yellow.
BTB is inexpensive and easily obtained in supply catalogs. You will find that you will use it for more than one experiment.

SAFETY PRECAUTIONS

BTB is a stain and will stain clothing. Always have an adult present and remind children not to put any solutions into their mouths.

LET'S MAKE FOSSILS

MATERIALS

1/2 cup cornstarch
1 cup baking soda
5/8 cup cold water
wax paper
leafs, bones, shells

PROCEDURE

Have an adult stir first 3
ingredients over medium heat.
Shape into about a dozen one inch balls.
Flatten a ball onto wax paper.
Press a leaf, bone, or shell into the dough.
Remove the leaf, bone or shell, leaving
an imprint.
Allow to dry.

EXPLANATION

Fossils are found in sedimentary rocks.
Prerequisites for fossils are:
1) organisms must be hard, such as bones,
teeth, shells
2) they must be in an oxygen-free environment,
away from predators
3) they must be in favorable heat and pressure
conditions

Four types of fossils:
1. Petrified fossils
Examples are porous wood or bones. Minerals seep
in, turning the porous material into stone.
2. Carbon fossils
Water and gas are squeezed out of the material,
leaving only carbon.
3. Molds and casts
The material leaves a hole in the rock in the
exact shape of the original specimen.
4. Trace fossils
Signs are left behind by an organism.
Examples: footprints, nests, burrows

GOOEY STUFF

MATERIALS

Half of a box of cornstarch (227grams)
200 ml water (7/8 cup)
Few drops food coloring
Container with airtight lid
Metal spoon

This mixture should stay fresh for about two weeks if stored in refrigerator in an airtight container.

SAFETY PRECAUTIONS
Always remind your children not to taste anything during a science experiment.

PROCEDURE

1. Mix the cornstarch and water together until texture is smooth. Add green food coloring. Have child dig into it with their hands, feeling the texture and observing the characteristics of this weird mixture.
2. Have your child describe to you the characteristics and make a list of them. They may notice it is both “runny” and “powdery” at the same time. How can that be? Encourage description and discussion.
3. Ask: What do you think will happen if you strike the “gooey stuff” with a metal spoon?


Always have the child predict what will happen, then actually do it, then discuss what they observed actually happened.


EXPLANATION

The liquid particles of the water are scattered throughout the solid particles of the cornstarch. The particles of one are dispersed throughout the other. Therefore, each substance, the liquid and the solid, retains its own individual characteristics (properties.) Hence, this “gooey stuff” has the properties of a liquid and a solid simultaneously- runny and powdery at the same time. Weird!

MAGNETIC MUSCLE

MATERIALS

Scissors
Ruler
String
One Bar magnet
Masking tape
Box of about 100 small paper clips
Large bowl

PROCEDURE

1. Cut 2 pieces of string, each about 1 meter long.
2. Tie one end of each string to each end of the bar magnet.
3. Tape the free ends of the strings to the top of a doorframe. Adjust height as necessary.
4. Ask, “Which part of the magnet do you think will attract paper clips the strongest?” Then, raise bowl full of paper clips so that the magnet touches the paper clips.
5. Slowly lower the bowl.
6. Observe what part of the magnet attracts the most clips.

EXPLANATION

Most of the clinging paper clips should be concentrated at or near the 2 ends of the magnet. All magnets are surrounded by an area called a magnetic field. This force moves from the north pole of the magnet, around the side, and into the south pole of the magnet. These magnetic force lines are closest together at the 2 poles, which give the 2 poles the strongest magnetic attraction.

SOUND WAVES

This activity is easy to set up, and gives the student a visual about how sound waves move.

MATERIALS

5 marbles
Flat surface

PROCEDURE

1. Line 4 marbles up in a straight line on a flat surface, close enough that they are touching each other.
2. Shoot the 5th marble so that it hits the end marble.
3. Observe. Discuss.

EXPLANATION

Each marble contains a certain amount of energy called Potential Energy. When the 1st marble hits the second marble, the Potential Energy is converted to Kinetic Energy (energy of movement) and passes its energy on down the line to the third marble, and so forth. This passing of energy from one marble to the next illustrates the way a sound wave is produced.