K-3 Lesson 3

Sunrise...Sunset - Bilingual Telemation Unit

K-3 Lesson 3:
The Earth Moves Around the Sun

Background:

The earth moves around the sun even though it appears as if the sun is moving around the earth. The shadows will vary depending on the height of the sun in the sky, the time of day and year and also the distance of the observer from the equator. Shadows are longest at sunrise and sunset and in winter. Shadows are shortest at midday, when the sun is high in the sky.

Shadows show clearly how the sun moves, so they can be used to tell time on a simple sundial. Time is indicated by where the shadow of an upright, or "gnomon" falls on a dial.

Concept:

Every day, the sun rises in the east, moves higher until about noon, and then moves lower until it sets in the west.

Purpose:

To demonstrate how shadows can help us to tell time.

Objectives:

Students will demonstrate that the movement of the sun causes shadows which were used as the first indicators of telling time.

Inquiry activities:

How can shadows help you tell time?

Will the shadows move? Why?

What are the shadows on your sundial similar to?

What else is moving besides the shadows?

Are the shadows the same size?

What makes the shadows' size change?

Materials:

1 flower pot or a sturdy cardboard paper plate

1 long stick

1 square piece of clay

Directed Lesson:

Securely place the stick in the middle of the flower pot or the paper plate, using the piece of clay.
Each hour by the clock, mark the position of the shadow on the pot or the paper plate as the sun moves.
If using a flower pot, at midday the light incidence is greatest. The shadow can be seen particularly clearly on the sloping wall of the pot.

Evaluation and Student Assessment:

Have students illustrate pictures where the sun is when they are sleeping and when they are eating lunch. This may also be done with a model of the earth, model of a sun, or flashlight.

Resources:

Laserdisc:
Windows on Science, by Optical Data, Primary Science 3

Teacher's Guides:
How the Earth Works, Reader's Digest, Dorling Kindersley Ltd, 1992

Earth, Moon and Stars, Great Explorations inMath and Science (GEMS), Lawerence Hall of Science, 1989

Invitations to Science Inquires, by Tik L. Liem, Science Inquiry Enterprises, 1987

El Sol, La luna, y las estrellas, by Jo Ellen Moore and Joy Evans, Eva-Moor Corp., 1992

Literature:
The Earth and Sky, A First Discovery Book, Scholastic Inc.

El sol siempre brilla en alguna parte, Allan Fowler, Childrens Press, Chicago

| K - 3 Lessons | Sunrise . . . Sunset | Return to Top |