Lenses+and+Magnification

Lenses work due to Refraction

Lenses and Refraction 1) Lenses work by changing the direction of light waves called refraction. 2) Refraction happens because light waves travel at different speeds in different mediums. 3) When light rays enter a medium at an angle, the change in speed causes the rays to bend, or change direction. 4) Different densities in the same medium can cause refraction as well. 5) Stars twinkling and a desert mirage are two examples of refraction cause by density differences. 6) Lenses, prisms, and water droplets can separate visible light into its component colors. 7) Light separates into its component colors because the angle of refraction is different for each color. 8) Red light is refracted the least, while violet is refracted most violently

Lens Shape and Refraction 1) A convex lens is thicker in the center than at the edges. 2) The shape of convex lenses causes light rays to bend and come together. 3) Where the light rays meet and cross is called the focal point. 4) The distance between the lens and the focal point is called the focal length. 5) Having objects and the eye beyond a convex lens's focal length will produce an inverted image. 6) Having objects or the eye closer than a convex lens's focal length will only magnify the image. 7) A concave lens is thinner in the center than at the edges. 8) The shape of concave lenses causes light rays to spread out or diverge. 9) The images formed by concave lenses will always be upright and smaller than the object. 10) The focal length of concave lenses is negative. 11) Highly curved lenses will cause the component colors of light to separate, blurring the image.





Optics for kids: http://www.optics4kids.org/home/content/other-resources/articles/lenses-and-geometrical-optics/

Good animated explanation of Magnification due to Convex lenses http://www.passmyexams.co.uk/GCSE/physics/concave-lenses-convex-lenses.html

Lenses in a Mircoscope https://optics.synopsys.com/learn/kids/optics-kids-lenses.html

Cameras http://physicalsciencecottrell.wikispaces.com/Optics+and+Sensors