Your heart was about the size of a walnut when you were born. Now your heart is about the size of your fist.

Materials:

• white carnation
• scissors or knife
• 2 glasses
• water
• red and blue food coloring

1. Get a white carnation with a long stem.
2. With help from an adult, very carefully cut the carnation's stem lengthwise, from the bottom to about halfway up to the flower.
3. Now fill 2 glasses with water.
4. Use food coloring to color the water in one of the glasses dark red.
5. Color the water in the other glass dark blue.
6. Put the glasses right next to each other.
7. Check the carnation a day later, and 2 days later.
8. Can you tell that the carnation has been drinking the water? You'll notice that the water travels up the tubes into the stem to reach the other parts of the plant.

The equator measures 24, 912 milesa round. It would take 25 million people holding hands to circle it!

Materials:

• soft leather scraps
• block of wood
• stapler
• marker
• sunscreen
• baby oil
• water

1. Take 4 scraps of leather and staple them to a block of wood.
2. Use a marker to label the strips "Suncreen", "Baby Oil", "Water", and "Natural".
3. Then rub a thick layer of sunscreen across the top of the sunscreen strip, baby oil over the baby oil strip, and water on the water strip. Don't put anything on the natural strip.
4. On a very hot summer day, take the strips of leather outside and let them bake in the sun. The next hot, sunny day, reapply the sunscreen, baby oil, and water and repeat the process.
5. Keep doing this every hot, sunny day.
6. At the end of the summer, closely examine how the strips of leather held up. Now imagine that the leather is your own skin!
   

Our blood always travels around your body in the same direction. It takes about 45 seconds for one trip.

In one day, you breathe enough air to fill about 500 party balloons !

Since the moon's orbit is elliptical, its distance varies from about 221,463 miles (356,334 km) at its closest approach to Earth to 251, 968 miles (405,503km) at its farthest point, with the average distance being 238,857 miles (384,392km).

Materials

• Paper
• Plastic comb
• Cloth (wool, polyester, or nylon)

1. Tear a sheet of thin paper into small pieces
2. Rub a comb with a cloth to give it a charge
3. Hold the comb near the pieces of paper, and watch as they cling to the comb.
4. Play a version of the game jacks called Static Cling jacks with a friend of by yourself.
5. Put the pieces of paper in a pile.
6. Rub the comb a little so that it picks up a single piece of paper
7. Rub the comb a little more so it picks up exactly 2 pieces of paper
8. Then try for 3 pieces of paper
9. Keep going until you pick up more or less than the correct number.
10. When it is your turn, you start with 1 piece of paper again.
11. Can you work your way up to 8 pieces of paper?

The U.S. government authorized Yellowstone National Park on March 1, 1872.