COLORED SHADOWS
Materials
- Red, Green and Blue water cellophanes
- 3 flashlights (with the same intensity)
- White board
- Any solid objects
Diagram
Results
3 flashlights were each covered with the Red, Green and Blue water cellophanes. They produced different colors of light as the flashlights were pointed in front of the white board. In the activity, 2 flashlights were held beside each other and the color (mixture) that was produced by these flashlights was observed. Different solid objects were placed in between or centimeters from the white board. As the flashlights were held (in a direction that was facing the white board) one by one or beside each other, the color/s of the shadow of the solid object/s were observed.
Discussion
Each flashlight had their corresponding water cellophane - Red, Green and Blue. When the flashlights were turned on and were held one by one pointing to the white board, each of the flashlight displayed a red, green and blue colored light. When all three of the flashlights were held together and pointed towards the white board, they displayed a white light since white light is composed of Red, Green and Blue lights. A solid object was placed centimeters from the white board. When the lights were held beside each other and were pointed towards the white board, the shadow of the object appeared like a rainbow. And as soon as 2 lights (Red and Green or Red and Blue or Green and Blue) were held together and were pointed towards the white board, they produced a different kind of color (color mixture) which was seen by the shadow of the solid object and the color flashed on the white board. Stating an example, Green and Blue lights were flashed on the white board and a pencil was placed between the white board and the flashlights. Although both Green and Blue lights were still seen, there was still a portion from the shadow of the object (where the Green light and Blue light met) where the color Cyan (mixture of Green and Blue) was spotted. All of this is because of the overlapping of the patches of light that produced a mixture of light by each pair of light. Also, it was observed that when the object got closer to the white board, the shadow of the object got darker and darker and basically turned black. This is because the object blocked the Red, Green and Blue lights.
Conclusion
Therefore, each pair of color mixed together forms another color based on this activity. When the colors of light are blocked, the only color we would see is black.
Sources
http://www.exploratorium.edu/snacks/colored_shadows/