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Not the OP, but a fourth grade substitute teacher made the claim that we always saw the same side of the moon because it didn't rotate. I don't know what got to

Not the OP, but a fourth grade substitute teacher made the claim that we always saw the same side of the moon because it didn't rotate. I don't know what got to me the most: that she didn't understand, that my attempt to explain it didn't go over, or that the other kids in the class didn't get it either. In any case, I've been working on improving my explanations ever since.

hervature 6y ago
What's your explanation now? I think people just get tripped up thinking about rotation of an object in circular motion and just ascribe one motion for the other. For example, if you imagine a newly reunited couple and they hug each other while simultaneously spinning, this is exactly what the moon and Earth are doing. I think most people would also say that the outside person isn't rotating. However, they would also say that the inner person is obviously spinning. Describing in words is often not the best way to impart explanations of physics, but the easiest way to show this concept for me is to imagine both people separately and consider a half turn. The inner person, rotates 180 degrees, simple rotation. What does the outside person have to do to get to the right position? They have to walk around the inner person to the other side and then rotate 180 degrees to see their partner again.
solipsism 6y ago
And your beef is that it does rotate, at a rate of one rotation per revolution? Sounds kind of pedantic to me, and confusing (certainly to kids).
- mercutio2 6y ago
  The fact that we live our lives in a non-intertial reference frame is pretty mind blowing to everyone, I suppose. Doesn’t seem like a small point to me.
- pjmorris 6y ago
  I'll grant that I was a pedantic fourth grader. And I'll grant that the other kids didn't care. Still, seems to me that the teacher could at least skip the topic if it's confusing.

hervature 6y ago

What's your explanation now? I think people just get tripped up thinking about rotation of an object in circular motion and just ascribe one motion for the other. For example, if you imagine a newly reunited couple and they hug each other while simultaneously spinning, this is exactly what the moon and Earth are doing. I think most people would also say that the outside person isn't rotating. However, they would also say that the inner person is obviously spinning. Describing in words is often not the best way to impart explanations of physics, but the easiest way to show this concept for me is to imagine both people separately and consider a half turn. The inner person, rotates 180 degrees, simple rotation. What does the outside person have to do to get to the right position? They have to walk around the inner person to the other side and then rotate 180 degrees to see their partner again.

solipsism 6y ago

And your beef is that it does rotate, at a rate of one rotation per revolution? Sounds kind of pedantic to me, and confusing (certainly to kids).

mercutio2 6y ago
The fact that we live our lives in a non-intertial reference frame is pretty mind blowing to everyone, I suppose. Doesn’t seem like a small point to me.
pjmorris 6y ago
I'll grant that I was a pedantic fourth grader. And I'll grant that the other kids didn't care. Still, seems to me that the teacher could at least skip the topic if it's confusing.