Grandpa Fenn's Workshop

The Shadow Clock

Grandpa has no watch. He pokes a stick in the yard and tells the time by the shadow. Toby thinks it is a trick. It is not.

Grandpa Fenn at the workshop door with his field notebook

Move the Sun

You are looking down at the yard from above. The stick stands in the middle. Slide the Sun across the sky and watch the shadow.

Time9:00 AM
Shadow pointsWest
Shadow lengthLong

Slide the Sun. Dots mark where the tip of the shadow has been.

Grandpa taps his chest. No watch needed. The Sun was the clock all along.

Why it works

The Earth turns. So the Sun seems to cross the sky from east to west. A shadow always points away from the Sun.

In the morning the Sun is in the east, so the shadow points west. In the afternoon it flips.

At noon the Sun is highest. A high Sun makes the shortest shadow.

Grandpa. A tall stick makes a longer shadow, so it is easier to read. But the clock is the same. Noon is always the short one.
Toby Fenn watching a shadowToby checks the shadow

Grandpa's notebook

A shadow points away from the Sun.

The shadow is shortest at noon and long in the morning and evening.

The shadow moves because the Earth turns, not because the Sun walks.

Big word for the day. Rotate. To spin around, like the Earth does every day.

Want to see the shadow tell a story first?

Open The Shadow That Moved

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