Why Do Mirrors Flip Left And Right And Not Up And Down?

On the Today programme this morning they had a science Q&A. They did the Qs just before I left for work, so unfortunately I missed the As.

One of the Qs was something along the lines of "Why do mirrors flip left and right, and not up and down?". Having heard the question before, I do know the answer, but still find it fascinating whenever it comes up, as it's one of those questions where the answer is completely obvious and entirely non-obvious at the same time (one of those kick yourselves when you find out the answer for not spotting it yourself type things).

The answer is, obviously (just to rub it in for those who don't know the answer already and like me didn't spotted it for themselves), that mirrors in fact flip front and back and not left and right. When you look at your reflection, your reflected left is still on your left and your reflected right is still on your right. The idea of these being flipped comes from the fact that your reflection is facing the other way and left/right depend on the direction you are facing whereas up and down don't.

I find it fascinating that the vast majority of people (including myself) pick up the misconception that mirrors flip left and right. Why is this? Is it due to discussing other people's left and right and considering our reflections as a separate entity? Do young children who are only just learning about left and right have this misconception?

Badges

Outside the tower at lunchtime I was passed by a group of school children. Most of them seemed to have various badges sewn onto their blazers saying things like "Academic", "The Arts", "Music", etc. I'm guessing this must be some variation on the scouts badge idea. I've never heard of schools doing this before.

Not sure how good an idea badges like that are in general though. Although, yes, they probably do act as an encouragement for many children to do the activities associated with them, they do seem to promote their use as a social scale (i.e. more badges is better).

Then there's the question of when do you award a particular badge. If you decide you need a achieving a certain performance in that particular area for that badge then surely you risk disaffecting the lower achievers. If you decide on a more varying scale depending on personal ability then you risk making the badges look meaningless.

At least with the scouts there is enough variety that you can cater to an individual's strengths. However, I'm still not convinced by them.