Investigation Lab: Shadows and Sunlight
Learn
In this hands-on investigation, you will explore how shadows change throughout the day as the sun moves across the sky.
What is a Shadow?
A shadow is a dark area made when something blocks light. When you stand outside on a sunny day, your body blocks some of the sunlight. The dark shape on the ground is your shadow!
Why Do Shadows Change?
The sun appears to move across the sky during the day. It rises in the east (morning), moves high overhead (noon), and sets in the west (evening). As the sun's position changes, shadows change too:
- Morning: The sun is low in the sky. Shadows are long and point away from the east.
- Noon: The sun is high overhead. Shadows are short.
- Afternoon: The sun is low again. Shadows are long and point away from the west.
Investigation Question
How does a shadow change from morning to afternoon?
Examples
Example Investigation Setup
Materials you will need:
- A stick or pencil standing upright in clay or dirt
- Chalk or small rocks to mark the shadow
- A clock or timer
- Paper and crayons to record observations
Sample Observation Record
| Time | Shadow Length | Shadow Direction |
|---|---|---|
| 9:00 AM | Long (about 2 feet) | Points west |
| 12:00 PM | Short (about 6 inches) | Points north |
| 3:00 PM | Long (about 2 feet) | Points east |
Practice
Complete these practice questions to check your understanding of shadows and sunlight.
1. What makes a shadow?
Think about what happens when something blocks light.
2. At what time of day are shadows the shortest?
When is the sun highest in the sky?
3. If it is morning and the sun is in the east, which direction will your shadow point?
Shadows point away from the light source.
4. Draw a picture of a tree with a long shadow. Is this a morning, noon, or afternoon shadow?
5. Why do shadows change direction during the day?
Think about how the sun appears to move.
6. If you wanted to make your shadow as short as possible, when would you go outside?
7. Can you have a shadow on a cloudy day? Why or why not?
8. Put these in order from shortest shadow to longest shadow: sunrise, noon, sunset.
9. If you measure a shadow at 9 AM and again at 3 PM, will the lengths be the same or different? Explain.
10. A student says "Shadows are longest at noon." Is this correct? Explain why or why not.
Check Your Understanding
Answer these questions to make sure you understand the main ideas.
Key Idea 1: A shadow forms when an object blocks ___________.
Key Idea 2: Shadows are shortest when the sun is ___________ in the sky.
Key Idea 3: As the sun moves across the sky, shadows change in ___________ and ___________.
Next Steps
- Try the shadow investigation outside on a sunny day
- Record your observations at three different times
- Compare your results with a classmate
- Continue to the next lesson to learn about graphing your data