The students will pour whole or 2 percent milk into a large bowl, completely covering the bottom. Then they will add one drop of yellow, red, blue and green food coloring to the middle of the bowl. Ask them to predict what will happen when they touch the tip of a cotton swab to the middle of the mixture, and then follow through to see if their hypothesis was correct. After that, they will add a bit of dish liquid to the tip of the swab and repeat the experiment to see a swirl of color. They can continue trying the soapy cotton swab in different areas of the bowl.
Purchase UV beads from a local school supply store or a science project store online. Have students place the beads in different zip-lock bags and apply different levels of SPF to each bag (15, 30 and 45, for example). They should write the number of SPF on the bag with a permanent marker. They should not put any sunscreen on one bag, which will act as the control group. After allowing the bags to sit in direct sunlight for five minutes, have the students analyze the differences in color changes amongst the beads.
Have students cut out a black circle in the shape of a flashlight face with a small slit in the middle. They will each tape the black circle over the face of their flashlights. Fill up a plastic box halfway with water, and place a mirror in the water so that it is leaning against the end of the box at an angle. They will point their flashlights so that the light shines through the water and on the mirror. By holding up white cards so that the mirror's light can reflect on it, rainbows will appear on the cards.
Allow each student to create colored spots on a coffee filter. Then they will take eye droppers and drop a little bit of water onto each colored spot. The coffee filters should be allowed to dry before proceeding on to the observation step. Each colored spot will be broken down into its components. Therefore, the secondary colors will separate. Have the students write down how many different colors they can see on their coffee filters.