Table of Contents

Facts About the World We Live On. . . . . . . . . . . . . . . . . . . . . . . . . . 3

Solar System Science! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

How We Travel the World. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

How Did We Eat Our Food?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Bonus Fact! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Works Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Author's Note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Facts About the World We Live On

This is our galaxy. It holds billions and billions of stars. The name is really easy to remember, just think of a popular candy bar! Did you get it? It's called the Milky Way!

Let's zoom in on this galaxy and get a closer look.

Hi, my name's Katie!

As we zoom in closer, you can see the solar system. Planet earth is the fifth largest planet. It has a diameter of roughly 8,000 miles!

The Earth is round, but not completely. It's a funny shape called an "oblate spheroid." All this means is that it's squashed at the top and swollen in the middle.

"Let's zoom in a little closer!"

As you can see in this picture, earth is covered mostly in water. Actually, roughly 71% of it is!

Also, about a fifth of the earth's atmosphere contains oxygen produced through photosynthesis.

As Earth orbits (or circles) the sun, it continues to spin. It takes 23.934 hours to finish a rotation and 365.26 days to finish circling the sun.

Earth's orbit is not a perfect circle. It is more in the shape of an oval. This oval is called an ellipse. Earth's orbit and rotation causes the seasons to change!

So let's sum up what we learned in this chapter.

*Our galaxy is called the Milky Way and holds billions of stars.

*Earth is the fifth largest planet, measuring to about 8,000 miles.

*Earth is not perfectly round, it is covered in 71% water, and about a fifth of it consists of oxygen.

*A rotation takes 23.934 hours and an orbit takes 365.26 days.

*The last fact is that an ellipse and a rotation cause our seasons!

"I hope you enjoyed this chapter, we've got lots more to learn!"

Solar System Science!

This picture shows a heliocentric model of the solar system. "Helio-" relates to the sun and "-centric" means central. So, this diagram shows how all planets orbit around the sun! A man named Nicolaus Copernicus came up with this theory in the 16th century.

Johannes Kepler was determined to figure out exactly how the planets orbit. Earlier in the book we learned the answer. Did you guess it? That's right, they orbit in an ellipse!

He eventually came up with three laws explaining this motion. His first law is called the Law of Orbits, the second is called the Law of Areas, and the third is called the Law of Periods.

Hello there!

Isaac Newton also came up with his own three laws. His laws were different from Kepler's though. He came up with three laws of motion in 1666.

To sort of add on, or summarize his three laws, he came with the law of universal gravitation. It explains earth's orbit and the reason for ocean tides.

Galileo Galilei was the man with the telescope. He discovered that Venus also went through phases. This would only happen if it was between the sun and the moon.

He also found that moons orbit Jupiter. This proves that other bodies can orbit around planets other than earth. Galileo helped prove that the heliocentric theory is right!

So let's sum up what we learned in this chapter.

*The heliocentric theory was discovered by Nicolaus Copernicus. It means that the sun is the center of the solar system.

*Johannes Kepler came up with the three laws of planetary motion: The Law of Orbits, The Law of Areas, and The Law of Periods.

*Isaac Newton came up with the three laws of motion and the law of universal gravitation.

*Galileo Galilei used a telescope to help prove that the heliocentric theory is right.

"I can't wait to learn more with you, let's go!"

How We Travel the World

The Compass Card showed north, east, south, and west. There are 32 points on the compass, and four main directions. Columbus noticed that magnetic north and true north would change.

The chip log contained a small chip of wood connected to a line on a fishing reel. The sailors would use a sand glass to figure out how fast the ship was going by counting how many knots rolled out before the sand ran out.

"Here's the old..."

Nowadays, the compass moves magnetically. It is made to always point towards north with the red arrow and south with the other side. This makes it much easier to know which way to go.

Instead of the chip log, modern boats use things called speedometers to tell how fast they are going. There a lot more dials and buttons on a ship, but the speedometer is used mainly for speed.

"...and here's the new!"