Lesson 3 of 19
When three line up, one shades another
Show on a big screenA tumbler stands in front of a lamp. A matchbox behind the tumbler goes dark. Why?
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The idea
Step 1 of 4
- The Sun, a ball in the way, and another ball.
- Light leaves the Sun in straight lines.
- The ball in the way blocks some of it. A shadow forms.
- If the shadow reaches the other ball, that is an eclipse.
The rule
The tumbler blocks the light. So the matchbox is in its shadow.
A body is any object, like a tumbler or the Moon.
A body in the way makes a shadow. If it lands on another body, that is an eclipse.
| What a shadow needs | On a table | Out in space |
|---|---|---|
| Something making light | A lamp | The Sun |
| Something in the way | A tumbler | Earth, or the Moon |
| Something behind, to land on | A matchbox | The Moon, or Earth |
Real sizes and gaps cannot fit in one picture. The pictures in this track are not to scale.
Try the lab to finish this lesson.