Solar School Activity Sheet

 

Solar Eclipse

Introduction

The sun provides us with the light and heat that we need to survive. It can also provide us with all the electrical energy we need, without causing pollution in our environment. And if you've ever noticed how the sea rises and falls each day, you'll know that the moon can also provide us with energy, due to the force of its gravity on the earth.

 

In this activity, you will learn more about the moon and the sun, and how they move in the sky. You will build a projection camera so you can safely observe the next full or partial solar eclipse. You can also use this camera to study the Sun when there's not an eclipse!

 

Background

Eclipses have frightened, mystified and puzzled man since antiquity. The Chinese believed that an eclipse was caused by a sky dragon eating the Sun.

Tablets found in north-western Mexico show that the Mayan Indians began making eclipse predictions and keeping records 2000 year ago. Even today, people travel great distances to witness this celestial alignment that brings awe and wonderment to all who see it.

A solar eclipse occurs on Earth when the Moon blocks the Sun's light due to the relative positions of the Earth, Moon and Sun.

The Sun's diameter is 400 times larger than the Moon and the Moon is 400 times closer to the Earth than the Sun. So, The Sun and the Moon cover approximately the same area of the sky - they appear to be the same size in the sky.

 

During a new Moon phase, the Moon is positioned between the Sun and the Earth. However, not every new Moon produces a solar eclipse, because the orbit of the Moon is slightly tilted with respect to the orbit of the Earth around the Sun. Only when the Moon's orbit brings it into direct alignment between the Sun and the Earth will the Moons shadow fall on the Earth.

 

The shadow is called the umbra, and during a solar eclipse sweeps darkness in a band 300 kilometres wide across the Earth at 1700 kilometres per hour! People inside the umbra will see the Sun completely blocked by the Moon. People outside this path, in an area known as the

penumbra, will see a partial eclipse, where the Moon only hides a portion of the Sun.

 

Introductory Activities

Make your own solar eclipse!

  1. Use an old tennis ball and a powerful torch to investigate how a solar eclipse occurs. Position the torch about four metres from a light-coloured wall in a darkened room. Now, tape some string to the tennis ball, and suspend the ball between the torch and the wall, about 40 cm from the torch. Move the ball slowly across the beam of the torch, and observe what happens to the shape of the torch beam on the wall. Try changing the height of the ball before you move it, and the distance of the ball from the torch.

    2.  

    Questions

    What happens to the shape of the torch beam on the wall as you move the tennis ball? What is the effect when you move the ball at a different height or distance? Does the room appear darker or lighter? What does this tell you about the relative positions of the sun and moon during a solar eclipse?

     

  2. See how much you can tell about an object from its shadow. Shine the light of an overhead or slide projector on a wall. Turn your back to the light and have a friend hold an object up in front of the light.

    3.  

    Questions
    Can you guess what the object is? How much of your ideas about an object are based on size? How can you make an apple as big as a beach ball?

  3. Have some fun with shadows and silhouettes. Using a bright light source like an overhead or slide projector, shine the light against the wall. Tape a piece of construction paper on the wall. Stand between the wall and the light until your shadow covers two-thirds of the construction paper. Have a friend trace your silhouette on the paper. Decorate a bulletin board with everyone's profile drawings.

Questions
How are shadows formed? Do the same principles of an eclipse work in your classroom?

 

Main Activity

See it for yourself!

Because of the intensity of the Sun's light, it isn't safe to look directly at the Sun during an eclipse. That's why you'll need to build a projection camera to protect your eyes. Once you've built the camera in this activity, you will be able to observe the contacts of an eclipse.

 

Materials:

 

  1. Cut a three cm hole in one end of the ice cream container.
  2. Tape the piece of aluminium foil over the hole. Put a small pinhole in the centre of the foil. This is where the sunlight will enter.
  3. DO NOT LOOK DIRECTLY AT THE SUN THROUGH THE PINHOLE!
  4. Cut a larger viewing hole far enough below the pinhole to allow observation without blocking the Sun.
  5. Tape a piece of white paper at one end of the other ice cream container. Then tape the two open ends of the container together.
  6. Hold the projector so that the Sun is behind you and over your shoulder. The sunlight that comes through the pinhole should fall on the viewing screen at the opposite end of the container.
  7. DO NOT LOOK DIRECTLY AT THE SUN THROUGH THE PINHOLE!
  8. If you can't find the right size ice cream container, use two sheets of white cardboard. Put a small pinhole in one. Stand with you back to the sun and hold the sheets about 60-80 cm apart, with one in each hand. Project the Sun's image through the pinhole on the other piece of cardboard.

 

Questions

  1. What causes the image to appear on the projection surface?
  2. What happens when you move the projection surface closer to you? Further away from you?
  3. What would the image look like if the moon were much closer to the sun? Or if the moon were much closer to the earth
  4. Why is it unsafe to view the Sun directly?
  5. Turn the beauty of an eclipse into words. Imagine that you are on the Space Shuttle Discovery. Write a poem that describes what you see. For inspiration, look for pictures, slides and films of recent missions. Share your poems and discover the different ways people interpret the beauty of a solar eclipse.