We surely do love our planet.  In the spring, the sun comes out, the blossoms bloom, and animals emerge from their winter homes.  That means we can do so much observational science!  Here are a few easy activities you can try at home that will teach you about light, animals, and plants.

How Many Colors in a Rainbow
Materials
A shallow glass baking pan
Water
White paper
Red paper
Blue paper
An outdoor table or chair

Process
1. Fill your pan about half full with water.
2. Take it outside and place it on the table so that one end is sticking out over the table edge.  Make sure it doesn't fall off the table!  You can use something or someone to anchor the pan onto the table.
3. Place your white paper on the ground where the sun is shining through your pan.
4. Slowly angle your paper until a small rainbow forms.  Experiment with the angle until you can get the largest possible rainbow.  What colors do you see?  What order are they in?
5. While holding your paper so that you can see the rainbow, gently place your blue paper on top of the white paper.  What happens to the colors?
6. Remove the blue paper and replace it with the red paper.  What happens now?
7. Switch back and forth between the white, blue, and red papers and observe how the rainbow changes.

What am I observing?
You created a mini rainbow.  Rainbows are caused by reflection and refraction of light.

Refraction refers to how light bends when it passes through different materials.  When the sunlight shines through the water, like the water in your glass pan, the light bends.  White light, like sunlight, is made up of all of the visible colors of light.  All of the colors bend during refraction, but because of their different wavelengths, they bend at slightly different angles.  When the light reaches your paper, you see all the different colors reflected.

With the white paper, you probably saw all of the colors clearly because white paper reflects white light.  When you used the blue paper, some of the colors likely appeared a little crisper.  Generally, the blue dye on the paper absorbs red light, allowing green and blue light to be reflected.  Since many visible colors are made up of green and blue light, the rainbow you saw on the blue paper likely looked similar to the rainbow you saw on the white paper.

The red paper likely changed the rainbow's appearance significantly.  The red dye absorbs blue and green light, and only reflects red light.  Removing blue and green likely left a mostly orange and red rainbow on the paper.

Model Moving Pollen
Materials
3 colors of chalk powder
3 cotton balls
3 small cups
Cotton swabs
Water

Process
1. Place each powder into a different cup, along with one cotton ball per cup.
2. Dip a cotton swab in water.
3. Roll the cotton swab along each cotton ball.

What is happening?
Pollen is a light, sticky powder that flowers need to make seeds.  In this activity, the chalk powder represents pollen, the cotton swab represents hair on animals, and the cotton balls represent plants.  As bugs and other animals touch a plant, they pick up pollen on their bodies, legs, and antennae.  When they move to other plants, they shed some of the pollen, helping the plants to propagate!

Grow a Bean in a Jar
Materials
A broad bean seed
Jar
Kitchen towel or napkin
Water

Process
1. Swirl a small amount of water around the jar.
2. Fold your napkin and place it in the jar.
3. Place the bean seed in the jar resting on the napkin.
4. Spray some water on the bean every few days.  The bean should start to grow roots in a few days.

What's going on here?
What you are observing is a process called germination.  The water causes the seed to break dormancy and initiate growth.  Bean seeds are relatively easy to germinate, as they don't need much more than water and oxygen.  Other seeds may also require sunlight, specific temperatures, scarification (a weakening of the coat), or stratification (chilling)!

We are so excited for Earth Week!  Of all the planets, Earth is definitely one of our favorites.  We've collected a few sustainability-themed activities that you can try at home.  Enjoy, and don't forget to reduce, reuse, and recycle!

Build a Pizza Box Solar Oven
Materials
Pizza box (the larger the better)
Pen or pencil
Ruler
White school glue
Black paper
Utility knife
Aluminum foil
Plastic wrap
Shipping tape
Wooden skewer or pencil
Sunlight, a warm day (above 75 degrees) and no wind

Process
1. Draw a square on the top of the pizza box's lid that is about one inch inward from each edge.
2. Use the ruler as a straightedge, and, using the utility knife, cut along each side of the square you just drew except for the side that runs along the hinge of the box.  Cut all the way through the cardboard on those three sides.  Fold the flap back slightly along the attached side.
3. Line the inside of the cardboard flap with aluminum foil.  Fold the edges of the foil over the flap to help hold the foil in place.  Glue the foil onto the flap, keeping it as smooth as possible.
4. Cover the opening made by the flap with a layer of plastic wrap.  Attach the plastic wrap to the edges using the shipping tape.  Make sure there are no holes in the plastic wrap and that its edges are completely closed.​
5. Line the inside of the box with aluminum foil so that, when the box is closed, the entire interior is coated with foil.  Glue the foil in place.
6. Glue or tape a sheet of black paper to the bottom of the box in the center.  This will act as your solar oven's heat sink.
7. Use a wooden skewer or pencil to prop the solar oven's lid up at about a 90 degree angle from the rest of the box.
8. To cook a s'more in your solar oven, place a marshmallow and a piece of chocolate between two pieces of graham cracker.  Place the prepared s'more on a small square of aluminum foil, and put it inside the solar oven on top of the black sheet of paper.  Put the solar oven in full, direct sunlight for at least 30 minutes, with flap of the oven facing the sun.

What's happening here?
Solar ovens use light and heat emitted from the sun to cook food.  They are designed to absorb more heat than they release.  Lining the box with aluminum foil allows sunlight to be reflected off of the foil and into the box.  The plastic wrap creates a greenhouse effect, allowing sunlight to pass into the box while retaining heat.  The black paper works as a heat sink, absorbing direct and reflected sunlight to become warm enough to heat up food placed on top of it.

Explore Climate Change with Before and After Pictures
NASA satellites take images from high above the Earth, and are able to capture the effects of climate change from a unique perspective.  Check out some of these incredible images here.

Are Rooftop Gardens a Good Idea?
Materials
Two shoeboxes, photo storage boxes, or half-gallon size cardboard milk cartons.
Sod
Exacto knife
A sunny spot outside on a hot day
Thermometer
Clock or timer

Process
1. Place one of the box's lids (or side of a milk carton) on the sod.  Using the exacto knife, carefully cut around the lid to get a piece of sod the same size as the lid.  Place the cut-out sod piece on top of the box.
2. You should now have one box with sod, which will represent your rooftop garden house, and one without, representing a house without a rooftop garden.
3. On a hot, sunny day, put the thermometer in the box with sod on it, close the box, and take it outside.
4. Place the box in a sunny spot.  Leave it there for 30 minutes.
5. When 30 minutes have passed, open the box and quickly read the temperature.
6. Put the thermometer in the shade near the box.  After it has adjusted to the shade, read the temperature.
7. Repeat these steps with the box that doesn't have sod on it.

What's happening here?
Rooftop gardens are a possible way to diminish the urban heat island effect.  Rooftop gardens generally absorb heat and insulate buildings better than tar and gravel roofs.  While both boxes were probably warmer than the temperature in the shade nearby, the box with the sod should have been relatively cooler inside compared to the other box.