Yardstick Eclipse Activity

Why do eclipses happen? Explore a simple scale model that demonstrates how the Earth, Moon and Sun align to create this spectacular solar event happening Monday, April 8th!


This video was created in collaboration with the Sci-Tech Discovery Center. This work is supported by the Simons Foundation and is part of its ‘In the Path of Totality’ initiative.

#TotalEclipseOfThePark #Eclipse #STEM #Space #Museum #StemEducation #STEMinASL #STEMvee

Transcript: On April 8th, a solar eclipse will be happening across the United States. This phenomenon happens when the Moon comes between the Earth and Sun blocking its light. But how can the small Moon block the giant Sun? You can create a simple scale model of what this looks like using a yardstick and two balls. A model is a representation of a person or thing, and scale is the ratio of the model’s size compared to its original size. For example, the Moon has ¼ the diameter of the Earth. To create our scale model, we can use a 1 inch ball to represent the Earth, and the Moon would be one fourth of that size- ¼ inch. We can also place our models at the correct distance to scale. I’ll put our Earth here on the 2 inch mark of the yardstick. In order to keep our model to scale distance, the Moon should be placed at the 32 inch mark. Can you use math to figure out how far away the Moon is from the Earth based on our scale model? Here’s a clue: The diameter of the Earth is almost 8,000 miles! This model is cool because it can show us how eclipses work. Let’s pretend this lamp is the Sun. When I turn down the light in the room, I can see the “sunlight” shining on my Earth model. Now, if I slowly move the Moon between the Earth and Sun, a shadow appears on the Earth’s surface. Even though the Sun is really big, the Moon can still block sunlight to us here on Earth. When the Moon aligns perfectly to block all of the Sun in one place, just like in this shadow, it’s called a Total Solar Eclipse. That’s what will be happening on Monday, April 8th in the continental United States. Check out the links below to see if you’re in the path of totality and learn more about this astronomical event!



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