Illustration of Scientific Concepts Stamp

This set of beautifully designed stamps, issued in April 1933, illustrates in vibrant colours, four modern scientific concepts presented in two of Israel’s leading Science Museums: Exhibited in the “Israel National Museum of Science” Haifa – Mixing Coloured Lights (colour mixing) – The exhibit demonstrates additive colour mixing and the concept of the three primary colours , or all three, using appropriate intensities, yields any colour. The intensities are regulated in this exhibit so that mixing all three lights renders white. The overlapping zone of any two circles appears as the complementary of the third colour. A Projected Slide, no screen (The Eye’s Memory) The visitor turns the wheel with a handle and observes a projected slide. When the rotatioin is fast enouth, a clear picture is obtained. This phenomenon results from a property called “the eye’s memory”. The eye remembers each picture for a small period of time and combines the sequence of pictures on the wheel to achieve one constant picture. Exhibited in “The Bloomfield Science Museum,” Jerusalem – Floating Ball (The principle of Lift) – The force that keeps the ball from failling out of the air stream is the same as that which holds up birds and aeroplance. When the ball tries to move sideways out of the air stream, the air pressure on the side of the ball outside the stream becomes higher than on the side inside the stream, so the ball gets pushed back into the stream. Wavy Ladders (Waves) – What goes up must come down . . . including waves! In this exhibit, one swings one of the arms and watches the resulting wave go up to the ceiling and “bounce” back down. Both science museums use the “touch and feel” method to spark the interest of Isarel’s young people as tomorrow’s generation of scientists and making science and technology accessible to the general public. The stamps with an information sheet are enclosed in a plastic protection sheet