Make a prediction about whether mold will grow faster in sunlight or in the dark. Conduct this experiment by putting two slices of bread in zippered plastic bags. Use white bread because it shows mold growth more easily. Place one in sunlight, such as in the classroom window. Place the other one in a shoebox and put the lid on. The mold will grow naturally. Check each piece of bread after a week to see which one has more mold growth.
The ultraviolet light from direct sunlight inhibits mold growth. Will ultraviolet indoor plant lights work just as well? Test this idea by conducting your bread mold experiment using two different types of light. Put two pieces of bread in zippered plastic bags and place one under an ultraviolet plant light. The other goes in the window. Turn off the indoor ultraviolet light at night to create nighttime for your bread. Observe your bread to see if the mold is growing at different rates.
You know that sunlight inhibits mold. Can sunlight stop or even reverse mold growth on a piece of bread? Use what you already know about mold growth to get two pieces of white bread covered in mold. Measure the amount of mold on the bread through the plastic zippered bag. Now, keep one piece of bread in a dark shoebox as your control, but put the other in a sunny spot and wait. Check on them every few days to measure and compare the mold growth.
The light from the sun and ultraviolet indoor lights is white light, meaning it uses the full spectrum of colors. What would happen if mold were placed in colored light? For this experiment, you'll need shoeboxes of similar sizes and colored cellophane. Cut a large window in each lid and tape colored cellophane over the window. Be sure to cover one with clear cellophane to use as your control. Place bread in zippered bags in the boxes and put all the boxes in the window. At the end of each week, measure the mold growth on each piece.