## Changing Planet

The Earth today is very different from the day it was formed, and it is still changing. There are mountains, deserts, forests, volcanoes, and oceans. They are all changing every day.

Do you know these Earth facts?

• 10% of the land surface is covered with ice.

• The highest point on land is Mount Everest at 2q,028 feet.

• The lowest point is the Mariana Trench in the Pacific Ocean at 35,820 feet below sea level.

• Earth is like a giant magnet with north and south magnetic poles.

• Almost 75% or 3 of the land surface Is under waterl

Water, Water Everywhere!

1. Use a 3-inch styrofoam ball.

2. Use a blue marker with a wide tip.

3. Draw a line around the middle of the ball.

4. Turn the ball and draw another line as in the picture below.

5. You have just divided the Earth into fourths, or four parts. Color three sections blue and one section green. The blue shows how much land on Earth is covered by water!

LO-O-O-NG Trip

What is the longest trip you have ever taken? Was it 100 miles? 500 miles? Maybe it was more than 1,000 miles. You probably didn't know it. but last year you traveled 620 million miles.

The Earth travels in a path around the Sun called its orbit. Earth's orbit is almost 620 million miles. It takes I year, or 365 days, for the Earth to orbit or revolve around the Sun.

Earth's orbit is not a perfect circle. It is a special shape called an ellipse.

1. How long does it take for the Earth to revolve around the Sun?_

2. How many times has the Earth revolved around the Sun since you were born?_

3. How many miles has the Earth traveled in orbit since you were born?

4. Draw an X on Earth's orbit to show where it will be in six months.

Experiment:

You can draw an ellipse. Place two straight pins about 3 inches apart in a piece of cardboard. Tie the ends of a 10-inch piece of string to the pins. Place your pencil inside the string. Keeping the string tight, draw an ellipse.

Make four different ellipses by changing the length of the string and the distance between the pins. How do the ellipses change?

0 0