Why does your hand look dry underwater?

January 25, 2010

Stick your hand in water and pull it out. You can tell that it’s wet, it “looks” wet. But then try this. Stick your hand underwater and look at it while it’s still underwater.   It doesn’t really look wet. And even more striking — Look at your wet hand in a mirror.  Now plunge your […]

Read the full article →

Making light rays in the classroom

November 14, 2009

In optics experiments, you often need to create lines of light.  You can do this with light boxes, but they’re expensive, and tend to  have too many rays to be useful.  Laser light boxes are great, but again, spendy. One teacher recommends using laser levels. These are the things made to help you hang pictures […]

Read the full article →

A long day at the Exploratorium…

May 5, 2009

Biologist Charlie Carlson over at my favorite alma mater (the Exploratorium museum of science in SF) snapped this photo of me, perky and bright-eyed… but my bench-mates?  Not so much.  Looks like they had a long day of interactive science. One thing we found curious about the photo was its graininess in the low light.  […]

Read the full article →

Through the looking glass

September 5, 2007

I’ve posted a new episode of my podcast, Science Teaching Tips Episode: 14 – Through the Looking Glass How big does a mirror have to be for you to see yourself in it? Exploratorium senior staff scientist Thomas Humphrey describes an activity you can use in your classroom to investigate simple optics.

Read the full article →