Good science demos and experiments?

I'm looking for good science demos and experiments that are suitable for a high school to university student level. I'm looking more for spectacle than learning value due to the nature of the usage of these experiments. Materials must be easy to procure (no need for online shopping, etc) and not too expensive (nothing over $100). A number of experiments and demos needed. All help would be greatly appreciated! Thanks!

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  • 1 decade ago
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    We had a kid at school win a blue ribbon at a state competition with this one. It seems simple but it's pretty cool I think.

    Science Project: Make a Battery Using a Lemon

    by Carl

    Using only a couple of things you probably already have at home, you can power a watch! Be sure to get a grown-up to help.

    Make a Battery Using a Lemon

    Level: Easy (Some adult supervision recommended)

    You'll Need:

    Wire clippers

    Steel paper clip

    18-gauge wire - copper

    A sheet of course sand paper

    Lemon

    Instructions:

    (This is where the adult will need to help)

    Using the wire clippers, strip 2 inches of the copper wire so that there is no insulation on it, then clip the bare wire off.

    Straighten out the paper clip and clip 2 inches off of the straight end.

    Using the sandpaper, sand the rough spots on the end of the wire and clip smooth.

    Gently squeeze the lemon. Rolling it with a small amount of pressure also works well. Be careful that you do not break the peel open.

    Poke the clip and wire pieces into the lemon. Get them as close together as you can without them touching anywhere.

    Touch the tip of your tongue (moistened with saliva) to the ends of the wires.

    You should have felt a small tingle at the tip of your tongue. A metallic taste should also have been present.

    Why?

    A voltaic battery, which is what the lemon battery is, changes chemical energy into electrical energy.

    The battery is made up of two different metals called electrodes. Electrodes are the parts of the battery where current enters or leaves the battery; in our case the electrodes are the paper clip and wire. The electrodes are placed in a liquid that contains a solution that can conduct electricity. This solution is called an electrolyte.

    The acid and water in the lemon are a water and electrolyte solution. In a solution like this, extra electrons collect on the end of one electrode. Meanwhile, electrons are also being lost from the other electrode.

    When you touch the ends of the electrodes to your wet tongue you close the circuit and allow a small amount of electric current to flow. The tingle you feel and the metallic taste are due to the movement of electrons through the saliva on your tongue.

    What Else?

    In our experiment a single lemon produces a mere 7/10 of a volt of electricity. If you connect two lemons together you can generate enough power to supply an inexpensive digital watch, which uses approximately 1.5 volts. To connect the lemons together use a flexible, thin wire to connect the silver wire of one lemon to the copper wire of the other. Attach thin wires from the other two wires in the lemon to where a battery's positive and negative poles connect to power the watch.

    Source(s): kids science fun website
  • 4 years ago

    My daughter obtained an A in this one. take an empty soda can and location it on a plastic lid to a bowl. Place one alkaseltzer below the can. When demonstration is able upload a couple of drops of water. The can will wiggle and transfer after which finally bounce up off the plastic lid.

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