Flying Through the Solar System
Grades 4-6

In this lesson students will study the Solar System, with emphasis on the terrestrial planets. They will be involved in hands-on activities to model information about Mercury, Venus, and Mars. To depict the size of the Solar System, students will create a model of it out of candy. They will also write a book about their travels through the Solar System, beginning at age ten and reaching Pluto at age seventy.

LOOK UP:#9 Mercury, Venus, and Mars

Students will be able to:

• Describe and compare the terrestrial planets of the Solar System
• Devise several products, such as graphs and models, to compare objects in the Solar System.

• One large card-stock postcard
• A Space Learning Log (paper booklet with entries for Mercury, Venus, and Mars)

Mercury Activity:

• 14 inches of string
• Foam core, or cardboard thick enough to push in pushpins
• Pushpins

Venus Experiment 1:

• Flask or bottle
• Balloon
• Baking soda
• Vinegar

Venus Experiment 2:

• Two thermometers (small enough to fit inside a jar)
• Small section of poster board
• Plastic putty to attach thermometers to the poster board
• Plastic wrap
• Glass jar

Mars Activity:

• Vinegar
• Steel wool
• Household chlorine bleach

Edible Solar System:

per student:

• 1 nine-inch paper plate
• Wax paper
• Popsicle stick
• Icing
• Ziplock bag
• Assortment of different kinds of candy. Examples are: butterscotch, Skittles, jawbreakers, Red Hots, jelly rings, Nerds, malted milk balls, chocolate raisins.

Background: (Teacher tells class:)

Long ago people thought that the Sun, Moon, and planets all moved around the Earth. If you watch the sky over a long period of time, it might seem that everything does revolve around the Earth. You see the Sun rising in the east and setting in the west every day. You can see that the Moon gradually moves eastward day by day (or, rather, night by night), changing its shape.
Most people believed this. This idea is call the "geocentric system." Only a few people believed that the Earth and other planets revolve around the Sun. Copernicus in 1514 and Galileo in 1609, however, said, correctly, that the Earth and the planets revolve around the Sun. (The Moon does revolve around the Earth.)

Mercury:
Mercury is the hottest planet and the one closest to the Sun. It takes 88 days for Mercury to travel around the Sun. One day on Mercury is equal to 59 Earth days. Mercury is slightly larger than our Moon. We can take pictures of its surface with satellites because it does not have an atmosphere. It has no moons. Its temperatures range from 800 degrees F in sunlight to - 300 degrees F in the dark.

Venus:
Venus is about the same size as the Earth. It is covered with clouds that are so thick that its surface is not visible through a telescope. It often appears to us in the evening or early morning sky, looking like a bright, white star. Its atmosphere is mostly sulfuric acid and carbon dioxide. The Sun's heat is trapped by Venus's clouds, so the temperature on the surface is about 900 degrees F. If you landed on Venus, you would be dissolved, roasted, or crushed by its atmosphere. There are mountains and lowlands on its surface. This planet rotates once every 243 Earth days and travels around the Sun in 225 days. Venus has no moons.

Earth:
From space, the Earth looks like a beautiful, blue jewel. Our atmosphere protects us from the Sun's heat and harmful rays, permitting just the right amount of sunlight through to provide plants with the energy to grow. About 70% of the Earth is covered with water. Some of the water is frozen in polar ice caps in the Arctic and Antarctica. We are located in the "life zone" of the Solar System. Our planet is not too hot or too cold for life to exist. The Earth rotates once every 24 hours and takes about 365 days to travel around the Sun. There is one moon orbiting our planet.

Mars:
Mars looks like a red star in the night sky. The red color comes from the rocks on Mars's surface. The rocks have a great deal of iron in them that rusts in the moisture in Mars's atmosphere. Mars has a thin atmosphere, and it is only about half the size of Earth. Its year lasts 687 days. It has two moons. Mars has polar ice caps and seasons that change as it revolves around the Sun. Two unmanned satellites, Viking I and Viking II, landed on Mars in 1975. They photographed the surface, recorded the temperature, and tested the soil. No life was found on the planet, but pictures show signs that there was once running water there. The water is now frozen in the soil and polar ice caps of the planet.

Ask the students if they believe it will someday be possible for us to live on other planets in our Solar System. Ask them to list in their Space Learning Logs three different ways in which the terrestrial planets are like the Earth. Have them list facts that they discover about the planets Mercury, Venus, and Mars.

START the video LOOK UP: Mercury, Mars, and Venus.

STOP the video for the students to participate in the activity that demonstrates the gravitational force of the Sun compared to the speed of the planets. Have the students attach an eraser to a piece of string. Pass the string through the straw. Attach a weight to the other end. Explain that this is a good model for understanding the Sun's gravitational force. The eraser represents a planet. The weight and string represent the inward pull of gravity from the Sun. As students twirl the string at different speeds, they will be able to see why the planets closest to the Sun move so quickly.

RESUME the video where the word "Mercury" appears.

STOP where Imagination says, "Well, I don't see anyone living on Mercury. Those extreme temperatures would put anyone off." Have the students record facts they learned about Mercury during this segment of the video in their learning logs. Explain that Mercury has an elliptical orbit. All the planets move around the Sun in orbits resembling ovals, or ellipses. Most planets follow very rounded ellipses, but Mercury's orbit is quite elongated. Have the students try to draw their own ellipse by doing the following:

1. Draw a five-inch-long line on a piece of foam core. At each end of the line, stick a pushpin into the foam core. Tie the string into a loop.
2. Put the loop of string around the pushpins. Place the pencil inside the loop, and pull it tight. Move it around the pins to draw an ellipse.

During the next section of the video, ask students to list how Venus and the Earth are alike and how they are different.

START the video where Imagination says, "Let's have a look at Venus."

STOP the video when Imagination says, "I don't see any creatures on Venus. All those clouds sound dreary."

Venus Activity:
Explain to the students that although Venus is almost the same size as the Earth, Venus is totally different. Its air is unbreathable carbon dioxide and pushes down with a force that is 90 times stronger than the Earth's atmospheric pressure. The atmosphere traps the Sun's heat, raising the planet's surface temperature to 870 degrees F. The surface is so hot that it glows in the dark.

Do the experiment from the video on making carbon dioxide, which is prominent in the atmosphere of Venus, as follows:

Begin by having the students put baking soda in the bottom of a flask or empty plastic soda bottle. Have them put vinegar in the balloon and attach it to the mouth of the bottle. Shake the bottle slightly. The balloon will soon expand. Explain to the students that it is filling with carbon dioxide gas, the same type of gas that forms a very thick layer covering Venus.

Next, ask to students to listen closely to the next section of the video to see if they can discover why Mars looks so red.

RESUME the video where the word "Mars" appears.

STOP the tape where Imagination says, "Well, there are two rocky moons, but there is no life there either." Have the students record facts they learned in the video segment in their learning logs. Next do the Mars Activity.

Mars Activity:
The surface of Mars looks red because it is composed of large amounts of iron. The moisture in the atmosphere causes the iron to rust. For a simulation of the surface, have the students make rust by combining vinegar and liquid bleach and adding a small piece of steel wool. (The steel wool will rust very quickly.)

RESUME the video where the animated Mercury, Venus, and Mars sing to explain why life cannot exist on them.

Make an edible model of the Solar System by covering a paper plate with a very thin layer of icing. Have the students choose different kinds of candy to represent the Sun, planets, and asteroid belt in the Solar System. Challenge them to think creatively. Have them draw their model of the Solar System in their learning logs and explain why they chose each piece of candy.

Continue a study of the Solar System. Have the class create a large wall mural of the Solar System, with written charts to explain what they learned. Hang the mural in the hall of the school or in a public building. Encourage students to write to NASA to ask questions about space.

Language Arts:
Have students write a story or a small book as if they are keeping a log while traveling though the Solar System. They begin their travels on the Sun at age 10. Their journey needs to end on Pluto at age 70. Tell them to include as much factual information about each planet as possible.

They are traveling at a constant speed such that they will reach the planets at the following ages (assuming they don't spend long on each planet looking around):

• Mercury - 10 years, 3 months
• Venus - 10 years, 5 months
• Earth - 11 years, 6 months
• Mars - 12 years, 4 months
• Jupiter - 18 years old
• Saturn - 25 years old
• Uranus - 40 years old
• Neptune - 56 years old
• Pluto - 70 years old

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Master Teacher: Teresa Hunsaker