Build a Sundial in the Yard

A straight stick about 12 inches tall

12-15 small flat rocks for hour markers

A permanent marker for labeling

An open, sunny area free from tree shade

Find a spot in the yard that gets sunlight from morning through afternoon without any shade interference. This is your sundial location.

Push a straight stick firmly into the ground. It should stand perfectly upright — use a level if you want to be precise, but eyeballing works fine.

Starting at whatever hour you begin (say, 9 AM), mark where the tip of the shadow falls by placing a small rock there. Use the marker to write "9" on the rock.

Come back every hour and place a new labeled rock at the shadow tip. Set a timer on your phone so you don't forget. 10 AM, 11 AM, noon, 1 PM, 2 PM...

By the end of the day, you'll have a beautiful semicircle of rocks around the stick. The shadow travels from west in the morning to east in the afternoon (in the Northern Hemisphere).

The next morning, check your sundial. Does the shadow land on the 9 AM rock at 9 AM? It should be very close. You built a working clock using the sun.

This is a full-day project with one-minute check-ins each hour. Perfect for a lazy weekend day in the yard.

Explain why it works: the Earth rotates, so the sun appears to move across the sky. The shadow tracks that apparent movement.

Your sundial won't match clock time exactly — sundial time and clock time differ slightly depending on the time of year and your longitude. That discrepancy is itself an interesting conversation.

Mark the noon shadow line clearly. It points true north (in the Northern Hemisphere). You just built a compass too.

Permanent sundials use a tilted stick (called a gnomon) angled to your latitude. If your child wants to go deeper, research gnomon angles together.