Measuring the Diameter of the Sun

 Measuring the Diameter of the Sun

    In this hands-on lab, we measured the diameter of the sun. Sounds a bit crazy, but it was certainly manageable, and the activity made me realize a lot. Even in the lab description, I discovered that there are many, many stars that are just as big as the sun, if not bigger! Regardless, we know that the sun is still extremely large in comparison to many other bodies in space. This is why the conversion steps in this lab are very important. These steps are clearly laid out in the directions which can be found below.

Student Materials (Per pair):

 Cardboard paper towel tube

 Aluminum foil square (10 cm x 10 cm)

 Graph paper square (10 cm x 10 cm)

 2 rubber bands

 Thumbtack or pin

 Metric ruler

 Sharp pencil

 Meter stick

 Masking tape

 Optional: Calculator

 Optional: Markers, stickers, other materials to decorate pinhole tube

1. Decorate your paper towel tube.

2. Place the aluminum foil square over one end of the tube and secure with

a rubber band, as shown in the picture.

3. Place the graph paper over the other end and secure with a rubber

band.

4. Use a thumbtack or push pin to carefully poke a small hole in the

center of the aluminum foil.

5. Create a guideline on the graph paper by gently marking one of

the lines near the center of the tube with your pencil. See figure

below.

Construction Tip:

The smaller your pinhole is, the better your pinhole tube will work. The foil rips easily, so be careful. If it does rip, get a new square of foil and try again. If the hole is not perfectly round, your pinhole tube will not work.

Part II: Using Your Pinhole Tube

1. Go outside with your partner. Take the pinhole tube, pencil, masking tape, and a meter stick with you. Decide who will

be in charge of the meter stick, and who will be in charge of the pinhole tube.

2. One of you should hold the meter stick like a pole. The other should sit on the ground and aim the foil end of the tube

at the Sun.

WARNING!

Do NOT look directly at the Sun or use the pinhole tube like a telescope!

Looking directly at the Sun will cause permanent eye damage!

3. Move the tube until you see a small image of the Sun on the graph paper. It looks like a circle of light, but it is really a

model of the Sun!

4. Tape the tube to the meter stick to stabilize it.

5. Adjust the tube until one side of the Sun’s image lines up with your guide line on the graph paper. Hold the tube steady and gently mark the other side of the Sun’s image.

Have patience! It is not easy to hold the pinhole tube still and keep the Sun lined up with the guideline.

 Measuring the Diameter of the Sun [SecEd WotU].pdf 

Here are some photos that I personally took during the lab: