This is meant to be handed out to the students.
Work in your groups to answer the following questions. The completed work sheets are due at the end of this class period.
a. Describe briefly what you think light is.
b. How does your group think light travels, in straight lines or in curved lines?
c. If you think it travels in straight lines, list two or more facts that support your claim.
d. If you think light travels in curved lines, describe what you would see if you were at a corner and a friend were around the corner. (See the picture below.) You should also draw how the light might travel. Write your description of what happens in words to the right of the picture.
Although we haven't proven it yet, radio waves are a type of light, just like the light that is illuminating this room. We can't see radio waves with our eyes, but our radio receivers can. We can't make radio waves with a light bulb, but our radio transmitters can. All you need to know now is that the radio waves we will be talking about move the same way light moves.
b. Suppose the Earth were a perfectly flat disk of radius 6,378 km and you were standing on a mountain top right at the center. How far could you see? Draw your line of site on the following picture. (Hint: The horizontal line, which is just the surface of the Earth goes on to a distance of 6,378 km.) Neglect the fact that the atmosphere would dim your view. (See picture below.) If you turned in each direction, how much of this flat Earth's surface could you see?
c. But the Earth isn't flat. The following picture is a cross-section of the Earth with an exaggerated mountain. Imagine someone is at the top of the mountain, but too small to see in this picture. Draw how far a person could see in each direction along the Earth's surface. How much of the Earth's total surface area do you think they could see? Estimate the fraction of its area. (Be careful with this one, the Earth is a sphere.)
Locations Satellite at Chicago Top of Alaska Iceland Scotland North Pole ------------------------------------------------------------- 1. Shuttle 2. Iridium 3. Globalstar 4. Ellipsob. As a satellite orbits the Earth what happens to its footprint?
Important Disclaimers and Caveats