Optics

click each image for larger version

 

One could augment observation of specimens with a lesson on how lens and microscopes work. I have not done this in depth, but have a few recommendations that I have tried. Please also see various www sites listed below that explain optics to kids.


Elementary School Level.
One can explain that there are lens (curved pieces of plastic in QX5 and glass in other microscopes) in a microscope “bend” light in ways that produce magnified images.

Here are a few ways to illustrate these principles.

  1. Make your own magnifying lens with drop of water (one flat and one curved surface). Click on image to see how to do this.
  2. Let kids play with different convex and concave lens. Have them look at newspaper print (a good test speciment). Let them deduce how these lens work. How does the curvature of the lens affect whether the image is magnified or minified? How does the degree of curvature affect the degree of magnification (or reduction)? Kids figure this out pretty quickly. You can buy a nice bag of cheap lens (concave and convex with different focal lengths) from Edumund scientific for $10 which will keep a whole class of kids occupied. http://scientificsonline.com/product.asp_Q_pn_E_3082272
  3. Make a big magnifying lens from a curved fish bowl or vase. Fill with water. Place a pencil at the back and look from the front. See that pencil appears to bend and enlarge comparing part of the pencil viewed through air and part viewed through the fish bowl.


Junior High School Level
You could potentially describe geometrical optics- ie. Basics of image formation using ray tracing diagrams. This is nice because it ties into math/geometry as well. There are several sites that describe this in more depth, so I will not go into this on this site. A useful demonstration is an optical bench to illustrate a real, inverted image and how different focal length lens affect the size and position of this image. Edmund scientific sells one for $60. It is a bit finicky, but possible to use for a teacher demonstration.

http://scientificsonline.com/product.asp_Q_pn_E_3111200

Edmund scientific also sells an optic demonstration kit ($25), but I have not tried it.

http://scientificsonline.com/product.asp_Q_pn_E_3098900_A_cmc_E_CROSS_SELL_A_Econo


WWW resources


Optical Research Associates

A few basic (junior high to high school tutuorials) on light and lenses
http://www.opticalres.com/kidoptx_f.html