When the Sun Plays Hide and Seek

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

When the Sun Plays Hide and Seek

August 20, 2017

On Monday, August 21, an amazing thing is going to happen: a total solar eclipse! The Moon is a giant ball, just like Earth, and as it goes around Earth, every once in a while it passes exactly between us and the Sun. That puts a shadow on Earth, the same way you can make a shadow on the wall with your hand. It will actually turn dark outside as the Moon slides across the Sun. Birds will stop chirping, and crickets will start. Since the Sun is about 400 times wider than the Moon but also about 400 times as far away, the Moon covers it exactly: if you’re in the right spot, you’ll see a perfect line-up. Just a thin ring of shimmering light will shine around the Moon, as the sky turns silver and blue and the stars come out. Everyone in the US will at least see a bite of the Sun taken out, so grab your eclipse safety glasses and check it out!

Wee ones: The Moon and Sun are both ball shapes, or “spheres.” Try to find 3 sphere shapes in your room.

Little kids: Turn on a light, and hold your hand near the wall or floor to make a shadow. As you pull your hand away from the wall, what happens to your shadow? Does it get bigger or smaller?  Bonus: The Moon is a ball about 2,000 miles wide, and our Earth is about 4 times as wide as that! About how wide is Earth?

Big kids: The full shadow, or “totality,” lasts only a couple of minutes. If totality starts at 12:59 pm and lasts exactly 2 minutes, when does totality end?  Bonus: The Moon’s shadow will race across the land at about 1,800 miles an hour. How many miles will it move in a minute? (Reminder if needed: An hour has 60 minutes.)

The sky’s the limit: The Moon is about 240,000 miles away from Earth. If the Sun were exactly 400 times farther away, how far away would it be?



Wee ones: Spheres might include toy balls (rubber bouncy balls, soccer balls, beach balls), balls of clay, or special light bulbs.

Little kids: The shadow will get bigger, since you’re blocking more lines of light.  Bonus: About 8,000 miles wide.

Big kids: At 1:01 pm.  Bonus: About 30 miles a minute. Our cars drive closer to 30 miles an hour!

The sky’s the limit: 96,000,000 miles, which is 96 million miles. The real distance is closer to 93 million miles.

Print Friendly, PDF & Email

About the Author

Laura Overdeck

Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.

More posts from this author