A few days ago I did this really interesting experiment, where I tested to see how flouride (F) in toothpaste can protect your teeth from ACID ATTACK (dum-dum-daaaarrr).

First I filled a small bowl with toothpaste (make sure the toothpaste has flouride in it). Then put the egg in it so only half the egg is covered. Leave it there for four days.

AFTER four days take the egg out and gently wash it. Put the egg in a cup of white whine vinegar. Recommended to leave it in the cup for seven hours, but we did it over night.
egg's been in floride toothpaste and then put in vinegarThis is the egg in the vinegar.

AFTER seven hours OR over night, take it out. The egg should have one side (the one with no toothpaste on) all squashy and squishy, and the other side (the one WITH toothpaste) should be very hard. It was squashy squishy because it had no protection from the flouride, and the acid melted the shell which is made up of calcium, like a tooth.

SO brushing your teeth with toothpaste that has flouride in it does help to protect your teeth from ACID ATTACK (dum-dum-daaaarrr). Since the 1960s, flouride is also sometimes added to drinking water, to help people to protect their teeth.

half the egg is protected the other half isn'tThis is the egg after being taken out of the vinegar.

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Today I made a boat made of only four things: Acetate, cardboard, leaves, and masking tape. What I did:
I first cut out the shape of the boat on acetate. Then I put on the cardboard sides and covered the whole thing in masking tape. Then, if you want, cover it (again) all over with silver foil. Note: if you cover it in foil, it will make it water-proof but you will not be able to have the sails.
To make the sails, find three dock leaves. Make sure one of them are smaller than the other two. Then tape them into the boat.
Fill 1/2 big bowl with water and put the boat in. Does it float? Yes? If it does, try to modify it so it can hold 25 pennies and still float for ten seconds.

PhotobucketThe plans (I didn't do the figurehead.)

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Today I built a rubber band powered car. I followed the instructions and after a few tries it didn't work very well. THEN I had a GREAT idea. It was this: TIGHTEN the wheels to the axel with masking tape instead of blue tack or poster putty. Then we had a couple more tries and IT WORKED!

For more AWESOME things that you can build, go to DESIGN SQUAD!

Here's a picture:
Rubber-band car
How this car is powered:
When you turn the rubber band, you are creating potential energy, which is stored in the rubber band. When you let go of the rubber band, the potential energy turns into kinetic energy, which is movement. The more potential energy you have, the farther your car will go.
Try taping a tennis ball to it and try to make it carry it!

Here is a picture of the same car, but modified to have a tennis ball on it:

When we tried it with the ball on, it hardly went anywhere. See if you can make your's do better! (Personally I think a baloon would be better than a rubber band.)

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