4-7 Lesson 7

Sunrise...Sunset - Bilingual Telemation Unit

4-7 Lesson 7:
When the Sun Turns Dark...

Background:

The moon, earth, and sun are on a straight line in space. Not all eclipses are complete. During a total eclipse of the sun, a small, dark nick is first seen in its edge. The dark area grows larger and larger. Just before it becomes total, the sky is darkened considerably, the temperature may drop, and there is a strange hush of nature's sounds. At this time, a pearly halo (the corona) appears around the blackened disk of the sun.

Concepts:

A solar eclipse occurs when the shadow of the moon blocks the sun's rays on some part of the earth.

Purpose:

To understand the causes of a solar eclipse.

Objectives:

Students will model the eclipse using a penny, light bulb and globe.

Students will set up the pattern that causes an eclipse.

Students will draw, write about and explain the occurrence of a solar eclipse.

Materials:

Globe

Penny

Tennis ball

Light bulb, with a stand

Procedures:

Whole Class Activity

Ask the students to model the revolution of the moon around the earth, using the tennis ball and the globe.
Give each student a penny. Darken the room. Turn on the light bulb
Instruct students to shut one eye and look at the light bulb across the room. (The light can be hidden with a penny held at the right distance from the eye.)

Conclusion:

What did you notice as you moved the penny between your eye and the light bulb?
Were you able to block out the entire bulb with the much smaller penny?
How far does the penny have to be from your eye to block out the light?
If you did this activity with a partner, would both of you see the "eclipse" at the same time?
Does everyone on earth see a solar eclipse when one occurs? Why or why not?

[Since the moon is smaller than the earth and close to it, its shadow falls only on a small portion of the earth's surface and is never more than about 200 miles wide.]

Follow-up Activity

With a light bulb, globe and tennis ball create the solar eclipse by aligning the tennis ball with the globe. Students write about their observations in their journals and share their written observation with their group as a check-up. Students draw and label the position of the earth, moon, and sun when an eclipse occurs. They also draw the stages of the sun leading to an eclipse.
Attach a ping-pong ball to the end of a long stick (e.g. a 1 m dowel). Take it outside and point it directly at the moon when it is up during daylight. Observe the ball as the sun lights its phase exactly as the real moon.

Assessment:

Older children visit classrooms of primary students to explain their investigations. Their report should include:

Model and explain the moon's movement

Model and explain the occurrence of an eclipse

Show drawings to aid their presentation

Put drawings on display

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