# Day 33: Mirror Lab Day 1

Monday, 29 September 2014

Struggle of the day: sighting the reflected ray of light from an image in a flat mirror. Here are the ways I’ve seen it done wrong:

Points the tip of ruler at the image rather than the entire edge of the ruler.

Points the other tip of ruler at the image of the pin.

So I went to a colleague to brainstorm other ways to teach kids to get a sightline. Maybe have them look through a straw?

I tried it. Tough to see through. The colleague then suggested practicing with sighting the clock. Step 1: get a ruler and a clock.

Step 2: grab both ends of ruler with your index fingers. Point both fingers at center of clock.

Not like:
Or any of a million variations that are ALL WRONG. Three more sets of guinea pigs students tomorrow to test with.

What was the warmup today in 7th and 5th periods?

I wrote this based on homework questions the kids were grappling with. Upon working this problem, I learned their biggest issue is figuring out how to convert into and out of units such as gigahertz and micrometers.

This day last year: Day 33: Final Instruments Due