Experimental phase

The best science is driven by curiosity, and kids are curious by nature. Instead of trying to keep their little hands out of the pantry or medicine cabinet, we’ve found a few fun and easy projects using common household items. And most likely, older teens and adults will find themselves curious, too.

While most of these projects are kid-friendly, we recommend having an adult around to supervise.

Potato battery

A potato battery is a classic science fair project because it’s incredibly easy and satisfying. A potato contains electrolytes, which can produce enough energy to power a small clock. A lemon, too, can produce electricity.

You’ll need:

Potatoes

Copper wire

Wire cutters

Galvanized nails

Three connected alligator clips

LED clock

How to make it:

- Stick one nail into each potato.

- Wrap the copper wire around one nail and one penny.

- Place the wrapped penny into the same potato with the wrapped nail. Ensure that the penny and nail do not touch.

- Stick a penny into the second potato.

- Connect the wire from the wrapped penny to the unwrapped nail. Secure with an alligator clip.

- Clip the other two alligator clips to the positive and negative sides of the LED clock. The clock should now be getting power from the potato.

Liquid solid

There’s a popular episode of the show Mythbusters, where host Adam Savage appears to “walk on water” by stepping into a pool of cornstarch and water. When he moves quickly, the corn starch and water briefly solidify under his feet, supporting his weight. When mixed, the two substances form a non-Newtonian fluid, in which the liquid briefly firms into a solid, resisting the penetration of a foreign object. A non-Newtonian fluid is called such because it defies the Newtonian laws of viscosity.

You’ll need:

Corn starch

Water

Glass or plastic container (Tupperware works)

Spoon

How to make it:

- Add equal parts water and corn starch into the container.

- Stir together—you’ll quickly feel a resistance in the mixture.

- Test the properties of the mixture. Place a finger on it, and you’ll see the mixture turn into a solid.

- Add more corn starch to make a more solid substance to play with. Try heating it the microwave for 45 seconds, or placing it in the freezer for a half hour, to see how the properties change.

Egg through a bottle

While a hardboiled egg is often significantly larger than the mouth of a bottle, the right amount of heat pressure will pull an egg right through.

You’ll need:

A small/medium hardboiled egg

A glass bottle with a mouth smaller than the egg

Newspaper

Lighter

How to do it:

- Peel the egg.

- Cut the newspaper into a 3-inch-by-3-inch piece.

- Fold the newspaper so it fits through the mouth of the bottle.

- Light the edge of the newspaper. While it is burning, drop it quickly into the glass bottle.

- Before the paper is completely burnt, place the egg on top of the bottle. The pressure will then suck the egg through the opening.

Black light ink

Petroleum jelly has many uses—one of which is ink that can only be seen under a black light. That’s because it contains phosphors, which, according to the University of Wisconsin, “absorb radiation and emit it as visible light.” Phosphor is also found on new $20 bills and in some laundry detergents.

You’ll need:

Petroleum jelly

Black light

Paper

How to do it:

- Dip a paintbrush or finger into petroleum jelly, and use the jelly to write words or make patterns on the piece of paper.

- In a dark room, shine the black light on the paper to reveal the writing or drawing.

- It works the same on skin. Dip a hand into the jelly and turn on the black light—the entire hand will glow in the dark.

Layered liquids

Test the viscosity of common foods and substances by adding food coloring to common liquids and pouring them into a clear glass. Oil-based salad dressings, in which the oil and vinegar separate, are a good example of the different properties of liquids, but other household substances can have the same effects.

You’ll need:

Food coloring

Tall, clear glass

Four small mixing cups

Cup of water

Cup of honey

Cup of vegetable oil

Cup of dishwashing solution

Funnel (optional)

How to make it:

- Pour honey, vegetable oil, water and dishwashing solution into four separate mixing cups.

- Add a drop of food coloring to each—use a different color for each liquid.

- Pour one-third cup of honey straight into the glass. Do not get any honey on the side of the glass. (This is where a funnel comes in handy.)

- Next, pour in one-third cup of dishwashing solution very slowly. The liquid will sit on top of the honey.

- Repeat the step with one-third cup of dishwashing solution.

- Try the next layer with water. Of the four substances, water is the least viscous, which means it more easily mixes with the others, so pour slowly.

- Let the liquids settle, and you’ll be able to see the different layers.