# Q & A: physics for a curious kid

Q:
Can anyone recommend a good magazine or other reading material for a 10 year old girl who is very curious about how things work? She is not especially gifted, but has an above average IQ in general, and interestingly shows some (to me) significant sparks of an extreme ability to process already acquired information to come up with a creative answer. An example: she listened attentively to some explanations of the twin paradox, and now is able to articulate it. I explained entanglement, and how instantaneous communication may violate relativity, and she understood (no, no minkowsky diagrams.. She is 10 years old). But get this, I asked how can she measure the speed of light, since it goes so fast, and she said to see how long it takes to get from a star (presumably to divide). So I asked how can she tell how far away a star is, and she immediately said to look at it in a telescope and magnify it until it takes up the whole image (yes, I know it's still a point, but she was intuitively thinking that by seeing how much you have to manifest you can tell the distance). Anyway, is there anything good relatively age appropriate? Thanks.
- Dan Smith (age 50)
New York, NY
A:

Your daughter has a wonderful attitude. It's a challenge to try to think of material that will encourage her to question and understand rather than simply march through standard courses. Here's some very random thoughts for starters, to be updated as colleagues (and maybe other readers) come up with better ideas.

Please let us know how these work out for your daughter, or what other materials you find. That'll be helpful for other students.

First, on that speed of light question, I bet she'd be interested in learning about how Roemer did it in about 1680. (There's a wikipedia article on it, but the link doesn't work right when pasted here.) It solved a problem with the method she suggested- how do you know when the light left the star? Here's the key. The moons going around Jupiter are like clocks, going around at regular rates. The clock looks like it gets a bit ahead when Jupiter is closer to us and behind when it's farther. (You can tell when it's closer or farther by her telescope method.) So you know the difference in time that comes from the changing distance. Now you just have to figure out what those distances are. That turns out to be another story, where the key is that Copernicus figured out how to tell how far away planets are using how their apparent positions changed as the Earth went around the Sun.

There are other ways to measure the speed of light, using that it's a wave. Studying some of those could be a great project.

Thinking about ways to weigh air could be another good project.

Louis Bloomfield at UVA has a Coursera course:  that might be good. Louis runs a great Q&A site, in some ways better than ours,  although unfortunately with ads. He's also got a book for the general public.

We've got ways to browse this site for topics she might be interested in. E.g. there's one question on how you can tell there's just two types of electrical charrge.

I remember some Isaac Asimov books about numbers and about physics that encouraged curiosity. I also have a vague memory that there were some great Russian physics problem books, e.g.  , but maybe for older kids.

One colleague has just written in that  might be good, although maybe too grown-up.

Mike W.

(published on 06/13/2015)