The Delight of Corner Reflectors


Corner reflectors are amazing.

They help cars see you (sometimes) on your bike at night.

There’s one on the moon that reflects back laser light.

They’re in the channel to help boats see

Obliging across the spectrum, corner reflectors be.

Here’s a great video about corner reflectors on the moon, which also talks about how corner reflectors work, and offers entertaining digressions like how astronauts deal with their poop.

Lesson Plan: A good lesson for students (perhaps Fifth or Sixth Grade, or even Seventh Grade, Eighth Grade, or older) would be to watch this video and make corner reflectors of their own using this science “snack” from the Exploratorium. The Exploratorium website is a wonderful resource for science teachers.

What is a Science Snack, anyway?
An Exploratorium Snack is a hands-on science activity. Science Snacks are tabletop exhibits or explorations of natural phenomena that teachers or students can make using common, inexpensive, readily available materials.

Science Snacks are divided into easy-to-follow sections that include instructions, advice, and helpful hints. Each one begins with a photo and/or video, a short introduction, and a list of materials. Other sections include assembly instructions, how to use the activity, and explain what’s going on, science-wise. Most Science Snacks can be built by one person; we indicate if a partner or adult help is needed, this is indicated. A section called “Going Further” offers interesting bits of additional scientific and historic information.

Why are they called Snacks rather than activities?
The Exploratorium is a science museum with hundreds of hands-on exhibits. Early in our history, other museums would ask for “recipes” to build and duplicate these exhibits, so we published a series of books called the Exploratorium Cookbooks. Teachers wanted to build classroom-sized, less expensive versions of these same exhibits, so we created Science Snacks as a way to bring our exhibits into the classroom. We published these in a book called The Exploratorium Science Snackbook.
Many of the original Snacks we built were based on museum exhibits. We’ve since branched out to cover content that spans science curriculum for grades 6-12.


If you’re interested in learning about the channel markers like the can buoy pictured up top, you can click here. The buoy is green, and has the #5, an odd number, so you know that it’s a buoy that marks the right side of the channel when leaving the harbor.

If you’re a squash player, you might already exploit the corners of the court to send a ball right back where it came from.