Two 38 mm spherical lenses; one is a double concave, the other a double convex, each with a focal length of 150mm. When placed together the net focal length is zero. (1-1/2" x 1-1/2" x 1/4"; .005Ib).
Great for optics experiments in the lab or classroom.
Defy gravity with this cool balancing eagle!
You don’t think recycling is cool? Get a look at this, we’re sure you’ll change your mind!
The Star-Ball Magnetic Puzzle is the perfect creativity tool for innovators, artists, writers, students, and you!
NEW 2016 DESIGN! This hip red tee features Pi to 1000 decimal places on an ultra soft 100% cotton shirt.
Build a tumbling robot that gets up right after it has fallen down, without any outside help!
Build your own windmill generator kit by recycling a plastic bottle!