☀️ Shadow Sundial
Track how a stick's shadow moves throughout the day and build your own ancient sundial to tell the time!
🧰 What you need
🔬 Steps
- 1
Go outside on a sunny day. Place your paper on flat ground and push the stick upright through its center into clay to hold it.
💡 Align your paper with north using a compass — it will make your sundial more accurate. - 2
Mark where the tip of the shadow falls every hour, starting in the morning. Write the time next to each mark.
- 3
Come back every hour throughout the day and add a new mark.
💡 Notice how the shadow is longest in the morning and evening, and shortest around noon. - 4
At the end of the day, connect the marks with lines — you have a sundial!
- 5
The next day, go out at a time you didn't record and use your sundial to estimate the time.
🧠 The Science
Earth rotates on its axis from west to east, making the Sun appear to move across the sky from east to west. As the Sun's angle changes during the day, the length and direction of shadows change predictably. Ancient people discovered this pattern and built sundials to measure time. Your stick (called a gnomon) casts a shadow whose position tells you the approximate time — the same principle used in sundials for thousands of years!
📚 Related Lessons
- 🌍 Day & Night — Why day turns to night and back again.