Determine the Screening Ability and Effectiveness of Suntan Lotions (page 2)
Design Your Own Experiment
- If sunlight causes tanning, does an absence of sunlight cause the skin to lighten? Place an adhesive bandage around the end of one finger. Leave the bandage on for 2 days. Remove the bandage and observe the color of the skin over the entire finger.
- Does the absence of sunlight affect all skin colors in the same manner? Test a group of people of different skin colors ranging from pale to dark brown. Ask each person to place an adhesive bandage around the end of one finger. Afer two days, remove the bandages and observe the color of the skin over the entire finger of each person tested.
Get the Facts
- Sun lotions and creams protect by absorbing radiation. Most sun-protecting products absorb radiation in the critical range of 2,900 to 3,200 angstroms. Use chemistry and physics texts to gain information about radiation. Find out what the electromagnetic spectrum is. What part of the spectrum causes tanning and burning of the skin?
- Lotions help to screen the skin from harmful solar rays. A greater protector is the earth's atmosphere. Find out how this envelope of gas around the earth shields the planet from the sun's powerful radiation. What changes in the atmosphere have resulted from pollution? What, if any, effect have the atmospheric changes had on increased skin disorders?
- The skin color of animals is affected by special cells called melanocytes. These cells contain a black pigment called melanin that is responsible for skin color, freckles, and suntans. Find out how light affects melanin. What effect does light have on the skin color changes in animals such as chameleons?
- The sun's rays are not all bad. When the skin is exposed to sunlight, cholesterol, a fat-related compound that is an essential part of many body cells, is converted to vitamin D. Find out about the uses of vitamin D. You could display the uses of vitamin D with a structural diagram showing the change of cholesterol to vitamin D in the presence of ultraviolet light (see Figure 25.3).
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.