Sun Position and Shadow Patterns

In this unit, students explore the position of the sun and moon to see how each of these objects relate to one another and also how they affect day and night on Earth. Once students have modeled how the motions of Earth and the moon cause patterns we see from Earth (specifically day and night and the moon cycle), they investigate another pattern: the sun’s changing position in the sky over the course of a day, which occurs in a predictable way. They also measure the length of shadows at different times of day to provide evidence for the sun’s changing position.

• The sun appears in different locations in the sky throughout the day, and the changing positions of the sun happen in a way that can be predicted.
• The sun produces light, and when objects block light from the sun, it creates shadows.

• Is there a pattern in the position of the sun in the sky during the day?
• Why does the sun’s position change in the sky in a predictable way throughout a day?
• How does the position of the sun affect the length of shadows?
• Are shadows something physical that can be held?
• How does the shadow of a common object outside, such as a tree or a flagpole, change over a day?

Axis: a straight line that an object rotates around

Day: the time between the sun’s rising and its setting

Moon cycle:  the changing appearance of the moon (as seen from Earth) as the moon orbits Earth

Night:  the time between the sun’s setting and its rising

Orbit:  to travel in a circle around an object

Pattern: something that happens in a regular and repeated way

Rotate : to move in a circle around an axis

Science:  all knowledge learned from experiments

Shadow: a dark shape created when an object blocks light 

Sun : a star at the center of the solar system

Sun and Shadows Telling Time

Jamie eats breakfast at 7:00 in the morning. He knows what time it is because he uses a clock. And Jamie knows what day it is because he has a calendar. Calendars tell us what day it is in the week. They also tell us what month it is in the year.

People haven’t always told time with clocks or calendars. They looked to the sky instead. People could predict when the moon would be round and bright. It appears that way every time the moon reaches that spot in its orbit around Earth.

People also used the movement of the sun across the sky to tell time. The sun does not stay in one place in the sky. It begins the day in one part of the sky. It always rises in the east. It then appears to move across the sky. It ends the day in a different part of the sky. It sets in the west. The path of the sun is a pattern. If we know where the sun is at one moment, we can predict where it will be at another moment.

 

During the hands-on activity, students investigate the position of the sun throughout a day and explore observable shadow patterns. Students use a straw to build a sundial to observe the shadow patterns. They record their observations before analyzing and discussing the data to make predictions about sun position and shadow patterns.