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Weekend · Science
Build a sundial that tells time (within 15 minutes)
A stick, a flat surface, and the sun. They watch time move.
90 min ages 7–12· Outdoor· Screen-free
How to do it
On a sunny day, around 9am: place a flat piece of cardboard on a sunny patch outside. Stick a pencil or chopstick (the 'gnomon') vertically into the center using clay or tape. Mark where the shadow falls with a marker, and write '9' next to it. Come back every hour, on the hour, until 4pm. Draw a line each time, label the hour. By afternoon you have a real working sundial — the lines spread out from the gnomon, hours marked. Talk about why the gaps are uneven (Earth's axial tilt, position on the globe). Bring it inside that night. Pin it to the kitchen wall.
What you'll need
Flat cardboard or wood square
FreeA chopstick or pencil
FreeA sunny day
Free