Mirror Half Reflection Optical Illusion

Desktop barometer and thermometer that uses the principles of buoyancy and air pressure. The thermomether (left) uses the principle invented by Gallileo in which the appropriate floating weight tells the temperature. The barometer (right) is a world mapamundi with fine etched continents.  Price: Less than $25

Optical illusion kit with Scientific approach to perception of illusions. Kit includes detailed manual and optics contraptionsPrice: $69.99

Kids can use this kit to build a kaleidoscope, periscope, and many other experiments with geometries, concave and convex mirrors. Price: Less than $12