How do we know the Earth is moving?

This post is my musings about transitioning 5th-grade students from an Earth-based perspective to a space-based perspective. Research literature shows that students need experiences to make sense of a space-based perspective to be able to explain the patterns caused by Earth’s motion. Here’s a sequence we could use.

One of the first patterns that children notice is the sun rising and setting. We can explain this pattern with a conceptual model of the sun moving around the Earth. However, other phenomena are not explained well by this model. The moving–sun–stationary–Earth model has limitations. When new evidence cannot be explained by our model, we must revise it.

What evidence do we have about Earth’s motion? Consider the following video that is an astronaut’s view of the Earth from space.

Video taken by Galileo spacecraft in 1990

This video is clear evidence that the Earth is moving. What other phenomena are caused by Earth’s motion?

Here’s a time-lapse video of stars near the North Celestial Pole.

How does a spinning Earth cause what we see in this video? How can we use a model to explain it?

The next example is a little more abstract. How could gravity be related to Earth’s spinning?

Gravity can be evidence that the Earth is spinning. Let’s think through this. Remember the last time you rode on a spinning ride? Maybe it looked something like this one. What did you feel? You feel pulled to the center. Like the girl in this picture who is pulled to the center.

The spinning of the Earth causes objects to feel pulled toward the center of Earth. At the equator, the surface of the Earth is spinning at 1000 miles per hour. So observing a force pulling an object towards the ground is evidence of Earth ʻ s rotation.

After considering these three phenomena, students may be more willing to consider that the Earth is moving. Then they can start using a space-based perspective and we can explain a lot more phenomena, such as why the path of the sun is different at different times of year. This is needed to explain the reason for the seasons, which is a middle school expectation.

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