Experimentally Speaking

Newton’s Inertia

One of Newton’s great accomplishments was his law of inertia. This law says that a body at rest stays at rest until it is acted upon by an outside force. You can prove this law by doing a simple experiment.

Materials Needed:

At least 20 coins of the same denomination

Flat bladed tool such as a metal spatula or a knife without a sharp edge.

Steps to Take:

1. Stack the coins in a single column on a flat surface.

2. Using your tool, take a level swing along the flat surface and strike the bottom coin from the column. Only the coin struck by the tool should move. The other coins should stay in their column.

All the coins in the column are inert at the beginning of the experiment. The tool acts as the outside force moving only the object it touches.

Johann Kepler figured out how planets stay in orbit around the Sun and how satellites stay in orbit around planets. You can make your own orbiting planet using some simple materials.

Materials Needed:

Plastic drinking straw

Two pieces of aluminum foil, 6" x 12" (15 cm x 36 cm) and 12" x 12" (30 cm x 30 cm)

24" (60.96 cm) of string

Steps to Take:

1. Cut the flexible neck off your straw, if it has one.

2. Thread the string through the straw.

3. Place one piece of aluminum foil under one end of string.

4. Crumple the foil into a ball making sure the string is firmly secured inside the ball.

5. Repeat the process with the other foil and the other string end.

6. Hold the straw upright in one hand with the larger foil ball coming out of the top of the straw.

7. Hold the smaller foil ball in the other hand.

8. Swirl the larger ball around the straw. Notice how its orbit doesn’t get any larger as long as you continue to hold the smaller ball.

9. Release the smaller ball. Notice how the orbit immediately increases in size.

The smaller foil ball represents gravity and its impact on orbiting bodies. Without gravity, the satellites would not be held in orbit. The larger ball would fly away. You can increase the size of the small foil ball to simulate a stronger gravitational pull. This heavier ball at the bottom of the straw results in a smaller orbit for the larger ball. This demonstrates how increased gravity holds the satellite closer to the planet.

If you spin the larger ball more slowly, it will fall downward. This is what happens when man-made satellites fall out of orbit.   Their speed is no longer in balance with the gravitational pull. They cannot maintain their orbits.

Moon Leap

The strength of gravity varies widely. A person jumping on Earth could jump six times as far on the Moon!

Materials Needed:

Grassy area

Two feet of masking tape or string

Tape measure

Paper and pencil

Helper

1. Make sure the grassy area is clear of sharp objects.

2. Place the tape or string at the beginning of the jump area.

3. With both feet behind the line, jump as far as you can.

4. Measure your jump from where your heels land.

5. Multiply your jump distance by 6 to calculate the length of your jump on the Moon.

Summary:

Gravity is an amazing thing. It is interesting to compare the strengths of gravity.

Big Bang Balloon

Most scientists believe the universe started as a result of a massive explosion that is still spreading material throughout the Universe. Make your own Big Bang version of the Universe.

Materials Needed:

Permanent marker

Balloon

Steps to Take:

1. Randomly make dots on your uninflated balloon.

2. Blow up the balloon and notice how the dots expand away from the center.

The balloon represents the expanding universe. The dots are the stars, planets, satellites, and other cosmic objects present in our Universe.

Almost everyone has worked with paper airplanes. These airplanes are gliders; they do not make power on their own. A very famous NASA glider in use today is the Space Shuttle. As it prepares to land, it becomes a huge glider. Make your own glider using some simple supplies.

Materials Needed:

Plastic drinking straw

2 paper clips

Sheet of construction paper

Transparent Tape

Steps to Take:

1. Cut flexible end, if any, off your straw.

2. Cut two strips of construction paper, 1" x 6" (2.5 cm x 15.2 cm) and 1" x 9" (2.5 cm x 23 cm)

3. Take each strip individually and tape the ends together to form circles.

4. Attach the circles to each end of the straw using a paper clip.

5. Fly your glider!

Your glider operates only on the power you supply to it when you throw it. As that power diminishes, gravity pulls the glider to the ground. See how far you can throw your glider.

Return To Top Of Page