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.
Explore the wonders of wind power with this amazing kit!
Illuminate both your room and your mind with this ingenious Periodic Table Lamp.
This genuine meteorite is great for the rock collector in your family!
Easily assemble a working alarm motion detector!
Build your own 10 inch kaleidoscope with this great kit!
Comprehensive collection of 30 fossils.
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