Once your program is downloaded to the RCX, press the green RUN key and notice that the LED on your light sensor turns on.

Press the black VIEW key until the black arrow is underneath the number 2 on the RCX. The display should change to show you what the light sensor on port 2 is seeing.

The two digits to the left of the "running man" will give you a lower number (less light reflected back) when over a dark surface and a higher number (more light reflected back) when over a lighter surface.

Now take readings from different objects around you.

What did you discover?

Did you notice that the amount of light in the room affects your readings? Objects closer to lamps and windows are obviously reflecting more light than objects farther away. Try to conduct your experiments in as evenly lit area as possible.

Also pay close attention to how shiny objects are. For example, the shininess of black electrical tape would reflect more light than the black square below.

Print out for best results.