Date: 1992

Grade(s): 4, 5, 6

Subject(s):

• Science/Astronomy

1. Work cooperatively or independently to produce a project.
2. Explore astronomical phenomena of interest.

Note to Teachers:

You may need to help the students pick appropriate projects. Some of these are more difficult than others. A word of warning though - just because a student hasn't displayed a strong aptitude in an area shouldn't exclude him or her from a difficult project that they want to complete. This may be their chance to excel. Use wise guidance. Some are faster to complete and may mean that a student should complete two. Use your judgment. You may also want to allow students to devise their own projects.

Introduction

You are to choose a special astronomy project of interest to you. The results of your project may be shared with your classmates. You will write a report. You may also need to develop a model, artwork, diagram, etc. to complete the project.

Some possible choices are listed below. You may want to pick a project not listed here. You will need to discuss the project with your teacher before you start. You should do the best job you can and dig into the subject as much as you can. Some projects are more detailed than others. You may do more than one project if time allows.

Movement of the Galaxies: (Requires two people)

One way astronomers determine if galaxies or stars are moving toward the earth or away from the earth is by use of the Doppler Effect. Light waves that move toward you appear closer together than light waves that are moving away from you. Light coming from a star or a galaxy that is moving away from the earth is shifted toward the longer end of the spectrum or the red end. You may think of this as the light stretching toward the red end of the spectrum. The stretching or jamming together if the light is moving toward you is known as frequency of the light waves. The change in frequency is known as the Doppler effect.

The Doppler effect occurs in all types of waves. In sound waves the pitch changes. A fire engine approaching you has a higher pitch. As it passes and moves away, the pitch of the siren becomes lower. This changing pitch results from the changing frequency of sound waves from a moving source. When the fire engine approaches the sound waves seem closer together. When the fire engine is going away the sound waves are farther apart. The pitch is determined by the frequency of the waves. The higher the frequency the higher the pitch. Sound waves change pitch just as the light waves changed color.

The Doppler effect can be seen in water waves. If you drop a pebble into a pond the ripples or waves are closer together nearer the spot where the pebble was dropped. They are further apart as you look further out from that spot. You may do a similar activity to show this effect in water.

This will help you understand the red shift in stars. The change to a redder color in the light waves from a star moving away from the earth is called a red shift. Since all the distant galaxies have red shifts we know that they are all moving away from us.

Materials:

1. shallow transparent glass dish
2. high intensity lamp
3. 2 plastic straws
4. rubber tubing
5. water
6. wood blocks

Teacher Note: This experiment should be directly supervised by you or another adult since electricity and water are involved.

Procedure:

Support the glass dish on wood blocks. Pour water into the dish until it is nearly full. Be sure to wipe up spills. Place the lamp underneath the dish so the light will shine upward through the water. Fit the plastic straw into one end of the rubber tubing. Turn on the lamp and darken the room.

Have a partner hold the end of the rubber tubing just above the surface of the water, and blow through the straw at the other end of the rubber tubing. You should observe the reflection of the water waves on the ceiling. When you can see the reflection of the waves your partner should slowly move the end of the rubber tubing over the surface of the water while still blowing, from one end of the dish to the other. Observe the waves in front of the moving tube and behind it. Note any difference and draw your observations. Then change places with your partner.

In your report describe the wavelengths in front of the moving source and compare them to the wavelengths behind the source. Tell which waves represent those of higher frequency. Relate this to the red shift.

Moon Craters

Scientists believe that many of the craters on the moon were formed by the impact of meteorites. Rock particles, resulting from the impact, often settle in rays that spread out from the crater. The size and appearance of a crater depend on two things: the size of the meteorite and its speed at impact.

You will set up a model to try to predict the effect of an object on the formation and appearance of a crater.

Materials:

1. balance
2. Cornstarch
3. goggles
4. meter stick or yard stick
5. metric ruler or foot ruler

Objects:

1. large ball bearing
2. BB
3. marble
4. ring stand and clamp
5. shoe box

Procedure:

1. Put your goggles on before beginning the activity. Fill the shoe box half full of cornstarch. Smooth the surface with your ruler. Drop the box lightly several times from about a half inch above the table to pack the cornstarch.

2. Place the ring stand and attached clamp next to the box. Place the meter stick or yard stick in the clamp. Position it vertically with the zero end resting on the table.

3. Using the balance, measure the mass (weight) of the ball bearing, BB, and marble. Record your results.

4. Using the meter stick as a guide, raise the BB to a height of 50 cm, or about 18 inches, if using a yard stick. Drop it into the shoe box.

5. Measure the depth of the crater and its diameter with the ruler. Record your observations. Smooth the surface of the cornstarch by dropping the box lightly. Repeat with the ball bearing and marble. Repeat several times with each object.

6. Record your observations in a chart showing the object's mass, depth of the crater, and the diameter of the crater.

7. To determine how speed affects the formation of a crater, use only one object, but vary the height from which you drop it. Make a chart to record your observations.

8. In your report describe your results. How does the speed and size of the object affect the formation of the crater?

9. You may want to find some pictures of craters on the moon's surface. Describe how they were made.

Sunspots are dark areas on the sun's surface. Sunspots are places where the sun's magnetic field is thousands of times stronger than average. Gases don't move as much in the sunspots. These regions are also cooler than the rest of the sun's surface. These sunspots change because of changes in the sun's magnetic fields.

You can observe sunspots by projecting them onto a piece of paper. Do not look directly at the sun!! This can damage your eyes.

Materials:

1. 3" x 3" square piece of Aluminum foil
2. Pin
3. Two sheets of white poster board about 1' x 1', no larger than 2' x 2'
4. Tape or Glue
5. Scissors
6. Something or someone to prop up one of the poster boards

Procedure:

1. Use the scissors to cut a square hole no bigger than an inch wide (doesn't need to be perfect) into the center of one of the poster boards.
2. Place the piece of aluminum foil onto a flat surface, using the pin, poke a fine hole no bigger than half a millimeter into the center of the foil.
3. Using the tape or glue, place the aluminum foil onto the hole in the poster board so that the pin hole is in the center.
4. Take both sheets of poster board out side on a good sunny day (You might not want it to be windy because stuff can blow away) and prop up the untouched poster board with a rock, brick, building, person, etc. Have it face the sun.
5. Hold up the pin hole poster board toward the sun so that it casts a shadow onto the poster board. The image of the sun should be in the center of the shadow. The further away you hold the poster board The larger the image is of the sun.