Some materials have reflective properties. When you look at yourself in a mirror, you are seeing an image of yourself. Because the mirror is very smooth and very reflective we say it is a regular reflection. Some materials are better reflectors than others. 

Imagine yourself bouncing a basketball on a smooth basketball court. It's easy to bounce and you know where it will come back. Now imagine you are in a dirt field. This time when you bounce the ball you are not sure where it will bounce back, because the surface is so uneven. Reflective materials are just like this. You have probably seen a lake or pond when it is perfectly smooth. It looks like a mirror because you can see the trees, mountains, and sky in the lake. But if a wind kicks up and breaks up the surface of the lake, the reflection is no longer even. We call this a diffused reflection.

Which of the following are true about reflections?

(Note: the questions are multiple choice and multiple answer. The student will need to check all the correct answers. This keeps the student from just "guessing" at the answers.)

A) A mirror is a regular reflection. 
B) A diffused reflection is a perfect reflection. 
C) A mirror is an irregular reflection.
D) Light bounces off smooth reflective surfaces best. 

Some reflectors are curved. If light hits an inward curved reflective surface (concave surface), the light comes back so it appears larger and upside down. Look at the illustration. The light hits the curved surface and bounces back in the opposite direction.  

Try this: Take a shiny spoon and look into it like you would a mirror. Notice that you're upside down. (Well not you but your image.)  

If light hits a convex object (outside curve), the image appears smaller but is right side up. 

Try it out: Take the same shiny spoon and look at yourself on the convex side.

Which of the following are true about curved reflective objects?

A) A convex curve is an inside curve. 
B) A concave curve is an inside curve.
C) A concave curve makes things appear upside down.

So now let's see how our understanding of reflections applies with your solar fan.



This experiment deals with the basics of reflection. When light reflects off a shiny surface, it reflects light and heat.


What will happen if you test your panel with a reflector and without a reflector? 

Record your answer in the logbook!



Solar fan, Mirror.


Take the Solar Fan into the full sunlight and make sure it is working.


Take the mirror and position it so that the sunlight reflects off of it and onto the solar panel.



Now take your other hand and shade the mirror, but not the panel. A. Did the fan run?

Record your answer in the logbook!


Now take your hand and shade the panel from the direct sunlight, but keep the mirror still shining on the panel. B. Did the fan run?

Record your answer in the logbook. 


With your hand still shading just the panel; note the speed of the fan. Now remove your hand and note the speed. C. Does the fan seem to run faster with both direct sunlight and a reflector?

Record your answer in the logbook. 


If you were to state a theory regarding how reflectors (mirrors) could be used to increase the efficiency of solar panels, what would you say?

Record your answer in the logbook.



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