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Have you ever wondered how people before phones and watches were able to tell time? They used the sun to make their own clocks called a sundial! Ancient people like the Egyptians and the Greeks all made sundials to know what time of day it was.
A sundial works because the Earth is constantly spinning, so the sun's position in the sky changes all day long. This makes the shadow from the gnomon slowly move around the dial, marking the hours without a battery or charger.
You can make your very own sundial at home!
What do you need?
- Pale construction paper or a 9-12 inch paper plate
- Stiff cardboard (a little bigger than your paper/plate)
- A large bowl (for tracing)
- Pencil or crayon (for tracing)
- Scissors
- Pencil or straight stick (This is your Gnomon – AKA: shadow maker)
- Mounting putty or soft clay
- 4 small stones or clear tape
- Dark marker
- Optional: compass and ruler
Try it yourself!
- Put your paper on the cardboard, flip the bowl upside down, and trace a big circle.
- Cut out the circle on both your paper and cardboard so they're the same size.
- Poke a small hole in the center of your circle. It doesn't have to be perfect, eyeball it or use a ruler. The hole should be just big enough for your pencil or stick to fit through.
- On the cardboard, put a small ball of clay or putty right in the center, push the eraser end of your pencil straight into it so it's standing up. Test it – if it wobbles, press the clay tighter
- Slide your paper circle down the pencil until it rests on the cardboard. Press the paper flat against the clay so it stays put. If your paper has marks, keep the blank side facing up.
- Now, pick a flat, sunny spot outside, somewhere it'll stay sunny for most of the day and won't get knocked over by people or pets. Check the current time, then set an alarm for just before the next hour.
- Use stones or tape to keep the base from moving. If it shifts, your times will be off.
- Check the current time, then set an alarm for just before the next hour.
- When the alarm goes off, head outside with your marker. See where the shadow hits the edge of the circle? Put a short line there and write the hour.
- Repeat this every hour until you run out of sun. You'll see the shadow move in an arc, kind of like the hand of a clock, just slower.
- If it's not going to rain, leave your sundial in place overnight. The next day, you can actually use it to tell time, no phone needed.
- Pro tip: at noon, the shadow should point north (unless you're in the southern hemisphere, then it's south)
Open and print the supply list for yourself!
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