Nancy B. Kennedy

It's raining!

Cloud Science

Every child learns the water cycle, including the concept of precipitation. Here's a great way for a child to visualize what happens when clouds become supersaturated with moisture. If only rain were as colorful as this!

What You Need

Tall, clear glass jar
Shaving cream
Food coloring
Eyedroppers
Small bowls
Water

What You Do

1. Fill the jar about three-fourths full of water. Let the water settle for a minute.
2. Mix food coloring with water in separate bowls. Make sure the colors are intense; squirt a lot of coloring into the water.
3. Squirt shaving cream over the top of the water, making sure to completely cover it.
4. Using the eyedroppers, start dropping colored water over the top of the shaving cream, drop by drop. Try to keep the colors separate.

What's Happening

When the shaving cream "cloud" becomes saturated with water in a particular spot, the colored "rain" breaks through and drops down through the water. You'll see that the drops share a similar mushroom shape as they fall.

Colored rain ready to go

Nature's Art

Fractal patterns in molasses

Nature is beautiful in so many ways -- colors, textures, sounds, aromas. I've just discovered a natural phenomena called "fractal patterns." These are naturally occurring patterns that appear in many forms -- ice crystals on glass, mountain ranges, river beds, leaves, lightning strikes, seashells, even galaxies.

With this activity, you'll make fractal patterns using kitchen ingredients. I've suggested two here -- ketchup and molasses -- and maybe you'll want to try more substances. Mustard? Barbeque sauce? You've got some great possibilities in your fridge!

What You Need

CD or DVD jewel cases
White paper (8.5 x 11)
Pencil
Scissors
Molasses
Ketchup

What You Do

1. Remove the CDs or DVDs from the jewel cases. Slip out the covers and playlists.
2. Trace around one case on the white paper. Make two cutouts. Place the paper in the jewel case and cut down to fit. Close the cases and put them with the white paper facing up on a table or counter.
3. Shake the ketchup bottle to make sure it's mixed well. Squeeze out a large drop onto one jewel case.
4. Pick up both cases and clamp them together, holding one case so that it's perpendicular to the other, so the spines don't bump.
5. Press the two cases together. Hold them with the edges facing up and pull them carefully apart. There should be some resistance.
6. Place the two cases on the table face up to see and preserve the pattern.
7. Using two other jewel cases, or after washing these, try the activity again with molasses. (The molasses pattern spreads out quickly. Putting the cases and the molasses in the fridge for a few minutes keeps the pattern intact a few seconds longer.)

What's Happening

Fractal patterns are the predictable results of a mathematical formula. If you divide a fractal pattern into parts you get a nearly identical reduced-size copy of the whole. The mathematical formulas are called "chaos equations" and by repeating fractal-generating equations many times, random outputs create beautiful patterns that are unique, yet recognizable.

You can see many of these patterns on this website of beautiful photos of fractal patterns.

Fractal patterns in ketchup

Homemade Gumdrops

An orange sugar rush

Okay, so my hand looks like an alien's -- I was covered in corn starch and jello at this point -- but I'm holding out a homemade gumdrop for a group of children at a bookstore in Rochester, N.Y., to see.

This is an easy treat to make... a pure-sugar bomb that you know you shouldn't let your kid have, but you do anyway because he's proud to have made it!

What You Need

Jello powder
Water
An eye-dropper
2 small containers
A fork

Open a packet of jello -- any flavor you like -- and pour the dry contents into a small bowl.

Pour water into another small container. Fill an eye-dropper with water and hold it over the jello container. Carefully squeeze out 8 or 10 drops, one on top of the other.

Using a fork, life out the wet spot from the jello and shake off the excess powder. Voile... a gumdrop.

Science Activities for Kids

Now You See It... But Is It There?

I just stumbled on this page of optical illusions. You won't believe what your eyes see! Sometimes the brain fills in missing "information" in ways that make you think you're seeing motion in a static picture or something that isn't even there!

Lava Lamp, Take 2

I thought I had made a really cool lava lamp using oil, water and salt. And it is a cool lamp, no doubt about it. (Scroll down to the bottom of this column to find it.) But, I gotta say... this one is even cooler! Alka-Seltzer makes this lava lamp go berserk! Try it some day when you're going berserk with your kids at home and have nothing to do.

You Will Need

A large, clear glass jar or pitcher
Water
Vegetable oil
Food coloring
Alka-Seltzer tablets

1. Fill the jar or pitcher about Ľ full of water. Fill the rest of the pitcher with oil, leaving an inch or so of space at the top (to prevent spills). Let the oil and water settle.

2. Break up a few Alka-Seltzer tablets into five or six pieces and have them nearby.

3. Squeeze a few drops of a single color of food coloring into the pitcher. (Yellow, because it looks similar to the oil, doesn’t show up as well as other colors.) Watch as the color drops settle on the bottom of the oil layer.

4. Drop in a piece of Alka-Seltzer. Look closely and watch the fireworks!

5. Continue to drop in pieces of Alka-Seltzer and more drops of the food coloring. Make new colors by dropping in a second color (red + blue = purple; blue + yellow = green; red + yellow = orange, etc.) and more Alka-Seltzer.

What’s Going On

Oil has a lower density than water, so it settles on top of the water. Food coloring doesn’t mix with oil, but instead falls through the oil to mix with the water. The ingredients of Alka-Seltzer—citric acid and sodium bicarbonate—react with the water to release bubbles of carbon dioxide gas that rise to the top and take colored water along for the ride. The gas escapes when it reaches the top, and the colored water falls in droplets back down through the oil.

Frozen Treat Beats the Heat

Temperatures where I live are in the 90s this week, so we're all looking for ways to beat the heat. Kids love it when their science lessons produce something to eat, so let's make some ice cream.

You Will Need

Measuring cups and spoons
Heavy cream
Vanilla extract
Sugar
Plastic freezer zip bags (gallon and quart)
Ice
Salt
Towel or gloves
Iced tea spoons
Coffee can (optional)
Peanut butter jar (optional)

1. Pour 1/2 cup of cream, 1/2 tsp. of vanilla and 1 tbsp. of sugar into a quart size bag. Press as much air as possible out of the bag and zip it closed.

2. Put the bag into another quart size bag. (Double bagging helps prevent leakage.) Place the double bag inside a gallon size bag

3. Fill the gallon bag with 4 cups of crushed ice (two trays) and pour 1/4 cup of salt over the ice and inner bags. Press the air from the gallon bag and zip it closed.

4. Wrap the bag with a towel or put on gloves (that ice is cold!) and begin to shake and squish the bag, making sure the ice surrounds the cream mixture.

If you don't mind a racket, you can do this activity with a plastic peanut better jar inside a coffee can (lids on both). Roll it around forcefully on a floor, along hallways, or down ramps -- whatever space you have!

5. Get out your spoons!

What's Going On

In order to melt, ice has to absorb energy. When you use ice to cool the cream mixture, the energy comes from the ingredients and from your warm hands. Salt lower the freezing point of water, so even more energy has to be absorbed for the ice to melt. This makes the ice cold enough to freeze your ingredients into ice cream.

See the Light

Fall is rapidly turning into winter. All the leaves have hit the ground here in the Northeast, and their reds, yellows and oranges have all turned to brown. You need a little color in your life!

You will need

3 flashlights
Plastic wrap in red, yellow and blue
Rubber bands
Clean, white baseball

1. Cut large pieces of red, green and blue plastic wrap. Fold them over four or more times to create squares of intense colors.
2. Form the squares of wrap over three flashlights and secure with rubber bands.
3. Place the baseball on a flat surface. (Prop it in place if necessary.)
4. Turn out the lights and block the light from windows and doors as much as possible.
5. Shine the flashlights onto the ball one at a time to see the baseball turn each color. Next, shine two colors at the same time. Try each combination of two colors to see what colors you get.
6. Try shining all three colors on the ball at the same time. What color does it become?

What's Going On

Red, green and blue are the primary colors of light. Combining them makes the secondary colors of light: yellow (red and green), blue-green or cyan (blue and green) and magenta (red and blue).

When you layer the three colors, the baseball becomes white again. That’s because you’ve made white light, which is not colorless but made up of other colors.

We see color because the eye has three receptors for colored light, one each for red, green and blue. Combinations of these colors of light stimulate the receptors, giving us the sensation of more than a million shades of color.

Why they're called sweat socks

We're suffering through a heat wave here in the Northeast. Sweat is a way of life! Your kids will like this easy -- and, um, odorous -- demonstration of how sweat forms.

You Will Need

Socks
Spray bottle
Water
Plastic bag

1. Wear your socks to play in for a few hours on a hot day. Take them off when you're done.
2. Spritz the socks with water a few times, and then seal them in a plastic bag.
3. Put the bag in the sun to sit for a few hours or overnight.
4. Open the bag -- if you dare!

What's Going On

Sweat is your body's way of cooling itself and keeping skin moist and flexible. One foot has more than 250,000 sweat glands! Sweat is a mixture of salt and water and doesn't really have an odor of its own. The icky smell the bag releases is caused by bacteria on your skin that eat the sweat and excrete a stinky waste. The water you spritzed on and the heat from the sun multiply the bacteria -- and the odor!

Apple Mummies

My son is studying ancient civilizations this year in sixth grade. Here's one of my favorite activities from my book, Make It, Shake It, Mix It Up that will put you in the mood for all things Egyptian.

You Will Need

Plastic baggie (quart size)
Powdered all-fabric bleach, washing soda or kitchen cleanser
Baking soda
Salt
Craft stick (or Popsicle stick)
Knife
Apple

1. In the baggie, mix Ľ cup of salt, ˝ cup of baking soda, and ˝ cup of washing soda or powdered all-fabric bleach. Close the bag and shake to mix.
2. Cut an apple in half lengthwise, through the core. With the craft stick, carve a face into an apple half. Push the stick into the apple, as you would to make a candied apple.
3. Plunge the apple half into the dry mix, making sure the apple face is covered.
4. Check on your apple over the next week. What happens to it?

What's Going On

You’ve made a mummy! The solution of sodium chloride (salt), sodium carbonate (washing soda), and sodium bicarbonate (baking soda) draws moisture out of the apple over time while preserving its shape and preventing mold from growing.

In ancient times, Egyptians used natron, a naturally-occurring salt found along the banks of the Nile River, to embalm bodies and preserve them as mummies. Earlier Egyptians simply buried bodies in the desert, where the heat and sand accomplished the same process.

Which Way Did He Go

In these times of economic chaos, it can be hard to know what path to take. Don't look to this arrow to help you decide!

You Will Need

3 x 5 card
Marker
Clear drinking glass or vase
Pitcher
Water

1. Draw a large arrow pointing in one direction on a 3 x 5 card.
2. Prop the card up against a wall. Position the empty glass or vase about 3 to 4 inches in front of the card.
3. Using the pitcher, fill the glass or vase with water. Watch the arrow as you do. What happens to it?

What's Going On

The arrow changes direction! How can that be? The water takes on the curved shaped of the glass, creating a lens. The lens acts to bend rays of light in a way that reverses the image of arrow. Try moving the glass farther away from the card—you’ll get a double image of your arrow.

Weighty Paper

These are bad times for newspapers. Your local paper is probably getting thinner every day, like mine is. So, I bet you think it's no problem to lift a simple page of newsprint. Let's try!

You Will Need

12-inch ruler
Section of newspaper

1. Lay a 12-inch ruler on the edge of a table so that about a third of the ruler extends over the edge.
2. Open out the newspaper section and place the pages over the part of the ruler on the table.
3. Hit the ruler sharply to try to make the papers fly into the air. Can you do it?

What's Going On

It can’t be done! But it’s not just the weight of the paper that makes it impossible; try it with just one sheet of newspaper. Air has weight. It pushes down on the paper with such force that you can’t move it. That’s because the paper has a lot of surface area for the air to press down on. Pressure caused by the weight of surrounding air is called atmospheric pressure.

Stab those Spuds

Memorial Day is coming up and guaranteed, someone will be pulling out a 10-pound bag of potatoes to make potato salad for your picnic.

Hand your children some of those potatoes and let them go to work on this activity.

You Will Need

Potatoes
Straws

1. Hold a potato firmly in your hand. (This works best on fresh potatoes, not the soggy ones in the back of the pantry covered with greenery.)

2. With the other hand, pick up a straw and cover the top end with your thumb. (Bendable straws do not work for this activity.)

3. Quickly and with as much strength as you've got, stab the potato with the straw. What happens?

What's Going On

You can stab the potato right through the heart! Even though your straw is just paper or plastic, it can cut through the potato without bending because you've increased the air pressure at work by covering the end of the straw.

Lava Lamps Redux

Remember lava lamps? I guess you'd have to admit to a certain age to answer that question!

Here's one of my favorite science activities. It's a simple sort of lava lamp made only with salt, oil and water. This is just one of the 44 science activities in my book, Even the Sound Waves Obey Him.

You Will Need

Tall drinking glass or clear jar
Cooking oil
Water
Salt
Food coloring (optional)

1. Fill the glass with about 3 inches of warm water. If desired, mix in a few drops of food coloring.
2. Pour in about 1 inch of cooking oil, either vegetable, corn or canola oil. (Olive oil doesn’t work well.)
3. Sprinkle salt over the glass. What happens?

What's Going On

The oil ends up on top of the water because it is less dense and because the liquids are immiscible (they do not mix). Salt, however, is heavier than water. When you sprinkle the salt into the oil, the grains sink to the bottom of the glass, carrying blobs of oil with them. As the salt dissolves in the water, the oil is released and floats back up to the top. Using warm water causes the salt to dissolve more quickly, making a more active "lamp."