2008 HS Photo Contest Pictures
2008 AAPT High School Physics Photo Contest Click on image to resize 
Third Place
- Natural
In this image, the water droplets are held together by the cohesive forces of the water molecules, the hydrogen bonds present in each droplets, created by the unequal distribution of electrons about the water molecule. They are spherical because that is the shape with the lowest surface area that can be created with a fixed volume, the shape itself caused again by the surface tension of the water. The blue reflection seen within the droplets is actually a reflection of the blue sky above. The blue light that is able to be reflected by the water droplets because the water has a different index of refraction than its surroundings (the leaf and the air). This means that light slows down when it enters the water, and speeds up when it exists, causing what is called a Fresnel reflection. The blue sky that is reflected from the water droplets is the result of the white light from the sun being scattered by the molecule present in the atmosphere. As blue light has a small wavelength, and the human eyes is more sensitive to said wavelength, the blue light is scattered much more than the other colors, and we perceive the sky as blue. Lastly, the sphere-like shape of each droplet causes it to act as a lens, magnifying the leaf beneath it. This is because light coming straight through has to travel a longer distance that the light coming from the side, creating a lens-like effect of magnification.
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