watermagic
Experiment #1 - The Disappearing Act
This activity demonstrates which substances really dissolve in water and which are only suspended in it. If the substance has dissolved, the solution (the mixture of water and the dissolved stuff) should look the same throughout. The particles will have broken up and will be spread evenly in the water. If the mixture stays cloudy, and the particles hang there and then settle to the bottom, you've made a "suspension" rather than a "solution."

Materials: 5 drinking glasses, 1 teas. each of salt, flour, baking soda, sugar, dirt

1. Fill the glasses with cold water.
2. Stir a spoonful of salt into the first glass
3. Stir a spoonful of flour into one glass, baking soda into another, and so on.
4. Wait for a few minutes to see what happens.

Experiment #2 - Make Your Own Water Filter
This activity is one way to clean muddy water. In many water treatment plants, dirty water is first allowed to settle in a large basin and then is filtered through layers of sand and gravel. This filtering method copies nature --- rainwater seeping through the ground gets cleaned the same way.

Materials: paper coffee filter, funnel, charcoal or fine gravel, sand, muddy water, a container

1. Place the coffee in the funnel.
2. Put a layer of crushed charcoal or gravel in the bottom of the funnel. Make another layer of sand above it.
3. Pour the muddy water through your filter into the container. What happens to the water? Is it clearer?

Experiment #3 - Center the Cork
This trick is guaranteed to drive your friends crazy!

Materials: a glass, some water, a cork

1. Fill an empty glass almost to the top with water.
2. Ask the kids to float the cork in the center of the glass. No matter how hard they try to center the cork, it will drift to one side.
3. Gently pour in some more water so that the surface bulges over the top edge of the glass. Place the cork in the water. Presto! It moves to the center where the water level is highest -- on top of the bulge. The water forms a convex surface -- the bulge -- because of surface tension.

Experiment #4 - A Water Drop Lens
Have you ever tried using water drops to magnify small print and pictures?

Materials: sticky tape, a used stamp, small styrofoam tray, plastic wrap, eye dropper

1. Tape the stamp that you want to magnify onto the styrofoam tray. Cover the tray with plastic wrap so the stamp won't get wet.
2. With the eye dropper, place a few drops of water on the plastic cover.
3. Experiment with different sizes of drops. Does the size of drops change how they magnify? Water drops curve up like the curve on a magnifying glass. They are miniature lenses.

Experiment #5 - Floating Needle
How can you make a needle float on water?

Materials: drop of vegetable oil, straight needle, tissue paper, bowl of water

1. Rub a little oil over the needle.
2. Place the paper carefully on top of the water.
3. Gently rest the needle on the paper. What happens to the paper and the needle?

The paper sinks because it quickly absorbs water through its tiny tubes or fibers. Why does the needle float? Although it's made of steel and should sink, it's held up by the invisible skin on the water's surface.


Experiment #6 - Water On The Earth
This activity demonstrates how much of the earth's water is fresh water.

Materials: 2-liter plastic bottle, salt, green food coloring, yellow corn oil, water

1. Put a few drops of green food coloring into the bottom of the plastic bottle.
2. Pour water into the container until just past the base of the neck.
3. Add 2-3 tsp. of salt to the green water. Explain that this water represents ocean water which is salty and cannot be used to drink or water fresh water plants.
4. Slowly pour 60ml of corn oil on top of the salt water in the 2 liter bottle. Explain that the corn oil represents 3% of the fresh water that is available on Earth. This is all the fresh water that is available for drinking, plant use and all of our other fresh water needs.

Experiment #7 - Mini Water Cycle
The purpose of this activity is for kids to discover how water is cleaned using a mini water cycle.

Materials: 16 oz. clear plastic cup, 3 drops of food coloring, 8 oz. warm water, ice cube, 8" square of clear plastic wrap, rubber band, paper towel

1. Place the cup on the paper towel. Put the food coloring in the cup and add the warm water.
2. Stretch the plastic tightly over the cup and secure with a rubber band.
3. Place the ice cube on top of the plastic wrap. Ask the kids what they think will happen when warm vapor from the colored water hits the cooler plastic above it (it will condense/form drops). What color will the drops be? (clear) Why? (As water evaporates, the food coloring is left behind.)

The kids have just seen how water is cleaned through the water cycle!

Experiment #8 - Alarming Aquifer
In this activity, kids will learn the parts of an aquifer. An aquifer is a layer of rock, sand, or gravel beneath the earth's surface that contains water.

Materials: clear plastic 1-liter bottle with spout and first 1/2" cut off, sand topsoil, two transparent straws, washed pea gravel, water

1. Put the gravel on the bottom of the plastic bottle to a depth of 2 inches.
2. Position two straws upright in the gravel layer. While holding the straws, pour 3 inches of sand on top of the gravel.
3. Add 1 to 2 inches of topsoil on top of the sand.
4. Slowly add water to saturate the sand and gravel. This water becomes the groundwater. Note the water's movement through the sand and gravel.
5. Suck the top end of one of the straws. Pinch the opening of the straw closed. Observe the effect of the pumping action on the aquifer. (The effect is similar to the effect of the pumping action of a well.)
6. Suck on the second straw and repeat the process. Note the effect on the level of the groundwater.
7. Suck on the straws several times and observe any changes in the groundwater model.

Experiment #9 - Ice Cube Lifting
The objective of this activity is to learn how salt lowers the freezing point of water.

Materials: glass of water filled, 6" long piece of string, three ice cubes, spoon, salt, 3 tbsp each salt, sugar, and pepper.

1. Place one ice cube into the glass of water.
2. Lay one end of the string over the top surface of the ice cube.
3. Sprinkle sugar onto that end of the string and the area around it.
4. Wait 1 minute. Try to lift the ice cube out of the water with the string.
5. Take the ice cube out of the glass using a spoon. Put another ice cube into the glass. Put one end of the string on top of the ice cube. Sprinkle pepper onto that end of the string and the area around it. Wait 1 minute. Try to lift the ice cube out of the water with the string.
6. Take the ice cube out of the glass. Put the last ice cube into the glass. Put one end of the string on top of the ice cube. Sprinkle salt onto that end of the string and the area around it. Wait 1 minute. Try to lift the ice cube out of the water with the string.

How does it work? Only the salt lowers the freezing point, causing the ice to melt. As the ice melts, enough heat leaves the ice cube to freeze the string onto the cube. That is why salt (not sugar or pepper) is sprinkled onto icy roads.

Experiment #10 - Making an Egg Float
The objective of this activity is to learn how salt affects the buoyancy of water.

Materials: raw egg, hard-boiled egg, glass of water, salt, tablespoon

1. Put the raw egg in the glass of water. Watch what happens. Take the raw egg out of the glass.
2. Put the hard-boiled egg in the glass of water.
3. Add salt, one tablespoon at a time, until something happens to the egg.
4. Once you have finished with step 3, take out the hard-boiled egg and put the raw egg into the glass. What happens?

Salt makes the water heavier. As the salt water becomes heavier, the egg is able to float. The key to floating is that the object (the egg) has to weigh less than the water it displaces (takes the place of). Adding salt makes the water heavier, so eventually the egg weighs less than the salt water it displaces. The raw egg weighs less than the hard-boiled egg, so it can float in both the tap water and the salt water.

Experiment #11 - The Water Bulge
This experiment will demonstrate how water creates a "skin" that allows leaves and insects to float on it.

Materials: plastic 8 oz. glass, 8 oz. of water, two drops of food coloring, 10 pennies or dimes, one piece of cardboard, tape

1. Put two drops of food coloring into the water. Pour the water into the glass.
2. Fit the cardboard around the top of the glass, forming a collar. Tape it in place. Hold the coins on the end of the cardboard and gently slip them into the water.
3. Notice how the top of the water bulges out above the glass and toward the cardboard.
4. Count the number of coins that you can add to the glass before the water overflows.

Water molecules are attracted to each other, creating a tight bond. This is called surface tension. Water molecules that are surrounded by other molecules are attracted in all directions. But the molecules at the surface do not have any water above them. They are strongly attracted downward to the molecules below. This prevents the molecules from spilling, even when the water level rises above the rim of the glass. Eventually, the volume of water above the rim of the glass becomes too great for the surface tension to hold, and the water spills.

 

Other Magic Pages

ScienceProject Home