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.
Learn about the objects in the night sky with this great set of cards!
Use this kit to conduct experiments with models to learn about forces and simple machines!
Easily assemble a working alarm motion detector!
This glass Erlenmeyer mug makes an excellent gift!
This black scorpion specimen is great for the classroom setting!
Giant 3D shark wall art to inspire adventure stories and lively conversations.