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Bigger is Brighter
Written by Janice VanCleave on June 15, 2009 – 3:48am -Optical instruments, such as telescopes and binoculars, are devices that increase the power of human vision. The aperture of an optical instrument is the size of the opening through which light enters (the objective end pointed toward a viewing object). The larger the aperture, the more light the instrument can collect and the better is the image of the object being viewed.
DISCOVER FOR YOURSELF
Use copy paper to make two cones, one with a 2-inch (5-cm) opening and the another with a 6-inch (15-cm) opening. Secure the cones with tape. Exact measurements are not critical, but encourage kids to use measuring tools.
Place two cups (500 ml) of dry, uncooked rice in a bowl. Set a second, empty large bowl on the ground outdoors. Then ask a helper to hold one of the cones, open end up, over the empty bowl. Holding the bowl of rice about 3- feet (1- m) above the cone, slowly pour the rice into the cone. Use a measuring cup to determine the amount of rice that the cone collected. Repeat the procedure using the second cone.
SUMMARY
The open ends of the cones represent different size apertures. The rice represents light from celestial bodies, such as stars. The cone with the larger opening should collect more rice. Like the cones, the larger the aperture of a telescope, the greater is its light-gathering ability.
Ideas for further research.
*Who invented the first telescope?
* What are the different kinds of telescopes?
* Why is the Hubble telescope so important?
Tags: aperature, objective lense, optical instruments, telescopes
Posted in Astronomy |
