Regional Science Centre, Khanapara

March 6: If you are interested to know all about your shadow then a visit to the Regional Science Centre is a must.

“One will be shocked to find that even after an object has been withdrawn, the shadow remains frozen on screen,” a science centre official said. The official said to freeze one’s shadow on a screen, one has to stand before a flashlight of the newly installed exhibit called “frozen shadow”.

The official said the flashlight casts a shadow on a special screen. After few seconds, the flashlight goes off and the shadow remains frozen on the screen for some time even the person moves away. The shadows are generally formed because of the obstruction of an object in the path of light, he added.

When an obstacle blocks a certain part of a light beam and the rest of the beam falls on a screen, a shadow of the obstacle is formed on the area of the screen where the light has been blocked. The shadow remains on the screen as long as the light and the obstacle remains in the same position. It disappears as soon as the light goes off or the obstacle is withdrawn.

In the first case, the shadow will merge with the darkness, while in the second, light will invade the shadow.

The official said the screen on which the shadow was frozen was an acrylic sheet coated with photo luminescent pigment such as strontium aluminates. Such a screen can absorb light by itself and re-emit for quite sometime when the light is withdrawn.

“Beyond the portion of your shadow where the flashlight illuminates, the screen goes on re-emitting light freezing your shadow even when you move away,” the official added.

He said this exhibit would help visitors understand the role of photochemical effect.

“All this is being done for the visitors and they should come and enjoy it. It can be beneficial to the younger lot as it involves a lot of science, too,” the official said.

Besides this the Regional Science Centre will soon have another new exhibit on “virtual chemistry lab” for its visitors. These exhibits with new technologies are being developed at Central Research and Training Laboratory of National Council of Science Museums, Calcutta.