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How Far Away is the Storm?

When you see a flash of lightning, start counting seconds like this: "and one and, and two and, and three and"- and continue until you hear a roar of thunder. Divide the number you get by 5 (for miles) and 3 (for kilometers). That will give you a rough estimate of how far away the center of the storm is.

Lightning and thunder take place at the same time, but light and sound travel to us at different speeds, and so reach us at different times. Light travels at 186,000 miles (300,000 km) per second and takes only a fraction of a second to reach us. We see lightning the moment it flashes.
However, it takes about 5 seconds for sound to travel a mile (3 seconds for a kilometer).
When a thunderstorm is near, the thunderclap sound is loud and sharp. When it is far away, it is a low rumble. Ordinarily, you can't hear thunder more than 10 or 15 miles (16 or 24 km) away. If you see lightning and hear thunder at just about the same moment, the storm is right above you.

What Causes Thunder?

You Will Need:
Ballon or paper bag


What to do: Blow up the balloon or the paper bag. Tie it closed with a rubber band or a piece of string. Then place one hand on the top and one hand on the bottom of the balloon or the bag and pop it.

What happens: You get a small clap of thunder.

Why: You created thunder by causing a small quantity of air to move fast. An object produces sound when it vibrates-moves back and forth or up and down. Humans only hear sound when an object vibrates at least 16 times a second- and not more than 20,000 times a second.
When a flash of lightning passes through the atmosphere, it heats the nearby air, and causes it to expand rapidly. It is this movement that causes the sound. A short crash of thunder results from a short flash of lightning. Rolling thunder occurs when lightning covers a large area, or when clouds, mountains, or other obstructions cause echoes.


Making a Bubble Blower


You Will Need:
Uncoated wire clothes hanger
Circular object, like a frozen juice can, or a thick crayon
Bubble mix


What to do: With the help of an adult, untwist the wire hanger and then wrap a piece of it around the can or thick crayon. Slip the can out. Leave about 4 inches (10cms) of straight wire for a handle.
Then bend the rest of the wire back and forth until it snaps. And now you have your bubble wand. 
Dip the wand into the bubble mix and wave it in the air.

What happens: You get a spray of bubbles.

Why: By waving the soapy wand in the air, you add the air that forms the center of each bubble.

Upside Down in a Spoon

You Will Need:
A shiny big spoon


What to do: The scoop of a spoon makes an interesting mirror. Just be sure the spoon you use is shiny and the larger the better. Hold the spoon up so you see yourself in the scoop.

What happens: When you look at the spoon you'll see your reflection upside down. Tip the spoon so it reflects other things that also appear upside down..

Why: Light rays travel in straight lines. They are reflected in straight lines, too. But when light is reflected from a curved surface, the rays leave the surface at different angles. The reflected images appears upside down because of the angle of the reflected rays of light.

Paper Napkin Trick

You Will Need:
Paper Napkin
Plastic cup of water


What to do: Drape the napkin over the edge of a kitchen counter or table. Place the plastic cup of water on one corner of the napkin about 1 inch (2.5 cm) from the edge.
Pull the napkin quickly away from under the plastic cup.

What happens: The napkin comes out-without any water spilling.

Why: The cup doesnít overturn because of the tendency of things at rest to stay at rest. Itís that old law of motion-inertia-at work. If it does spill itís because youíre not pulling the napkin fast enough or with enough force.

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