WEBELOS

Scientist
Heart of America Council

Inertia

Materials: 1 fresh egg, 1 hard-boiled egg, and a soup dish.

What to do: Give each egg a spinning motion in a soup dish.

What Happens: Hard-boiled egg spins longer.  The inertia of the fluid contents of the fresh egg brings it to rest sooner.

Bernoulli‘s Principle

Materials: Two ping—pong balls, 2 feet of thread, some masking tape and a drinking straw.

What to do: Tape each ball to an end of the thread and hold the center of the string so that the balls dangle about 1 foot below your fingers and about 1 or 2 inches apart.  Have the boys blow through a straw exactly between the balls, from a distance of a few inches.  Instead of being repelled, they will be attracted.

What happens: The air current directed between the ping-pong balls reduces the intervening air pressure.  Stronger pressure from the far sides pushes the balls together.  The strength of the air from the straw will determine how close the balls will come.

Time and Clime
Heart of America Council

Glass Jar Barometer - -

A barometer tells you if the air pressure is high or low. If the air is calm and pleasant, the barometer is rising. If it’s unsettled and stormy, the barometer is falling. Make a simple barometer to tell you if it’s going to be a day to stay indoors or play outside.

1. Cover the mouth of a glass jar with a piece of balloon held in place with a rubber band.

2. Glue one end of a straw to the center of the balloon. (You may have to trim the straw extending over the jar if it pulls the balloon too much.)

3. Hammer a ruler about 2” into the ground.  Set the barometer next to it.  Notice where the straw points.

4. Each day, check the barometer to see if the straw is rising or falling from the point where it was the day before.  If the air pressure outside the bottle is greater than the pressure inside the bottle, the balloon will drop slightly causing the straw pointer to move up, indicating rising air pressure.  If the air pressure outside the bottle is less than the pressure inside the bottle, the balloon will rise causing the straw to drop, indicating falling air pressure.

Make Crystals You Can.Eat
Heart of America Council

Pour 1 cup water into a small pan.  Cover and bring to a boil.  Turn off the heat and add two cups of cane sugar.  Stir until well-dissolved and let cool.  Pour the sugar solution into a -tall glass.  Lie a piece of clean white string to a pencil or stick and place -the stick across the glass so that the string hangs down into the liquid.  Put the glass in a cool place for a few days.  In a short time small crystals will form along the sides of the glass.  Soon they will begin to cling to -the string.  After several days, large crystals, hard as a rock, will have formed around the string.  Lift the string out of the glass and taste some delicious homemade rock candy.

Optical Illusions
Heart of America Council

Can the human eye see something that isn’t there?  Decide for yourself.  Hold a spoon about 12 inches in front of your eyes.  Look beyond the spoon, toward the corner of the room.  You should be able to see two spoons.  Now hold out two pencils, separated by a finger.  Look beyond the pencils.  Do you count four?  In this test, most people see double images because their eyes are out of focuss.