To learn about the damaging effects of sunburns and tanning, and how sunscreens work to protect us from the sun’s harmful UV rays.
This lesson is part of the Skin Deep Project, which examines the science behind skin. Skin Deep is developed by AAAS and funded by Neutrogena. For more lessons, activities, and interactives that take a closer look at the science behind skin, be sure to check out the Skin Deep Project.
In this lesson, students will discuss what they already know about the impact sun exposure has on their skin and what they typically do to protect themselves, if anything. Using a number of online resources, they will then learn how to care for their skin, the damaging effects of sunburns and tanning, and how sunscreens provide protection from the sun's harmful UV rays.
Exposure to the sun (radiation) damages skin cells and can lead to gene mutations or uncontrolled cell division (cancer). Understanding the interdependency of the various types of cells in the body can help students appreciate the danger involved. (Benchmarks for Science Literacy, p. 113.)
You should make students aware that health technology exists to help reduce people's exposure, increase the body's resistance, and minimize the harmful effects due to conditions that threaten health, such as UV radiation. Historically, the most important effect of technology on human health has been through the prevention of disease, not through its treatment or cure. The creation of sunscreens to prevent skin cancer is a good example.
It should also be emphasized that, with reasonably good nutrition and sanitation, the human body recovers from most infectious diseases or conditions (like sunburn) by itself, without intervention of any kind. (Science for All Americans, pp. 123–126.)
Research shows that students at this level have a number of misconceptions about genetics and the basic workings of cells. For example, when asked to explain how physical traits are passed from parents to offspring, some high-school students believe that traits are inherited from only one of the parents (for example, the traits are inherited from the mother, because she gives birth or has most contact as children grow up). Other students believe that certain characteristics are always inherited from the mother and others come from the father. Some students believe in a "blending of characteristics." In addition, students of all ages believe that some environmentally produced characteristics can be inherited, especially over several generations. With regard to cells, preliminary research also indicates that it may be easier for students to understand that the cell is the basic unit of structure (which they can observe) than that the cell is the basic unit of function (which has to be inferred from experiments). Research also shows that high-school students may hold various misconceptions about cells after traditional instruction. (Benchmarks for Science Literacy, pp. 341-342.)
Ideas in this lesson are also related to concepts found in these health education standards:
- HEALTH EDUCATION STANDARD 1:
Students will comprehend concepts related to health promotion and disease prevention.
1. analyze how behavior can impact health maintenance and disease prevention.
3. explain the impact of personal health behaviors on the functioning of body systems.
- HEALTH EDUCATION STANDARD 2:
Students will demonstrate the ability to access valid health information and health-promoting products and services.
1. evaluate the validity of health information, products, and services.
- HEALTH EDUCATION STANDARD 3:
Students will demonstrate the ability to practice health-enhancing behaviors and reduce health risks.
1. analyze the role of individual responsibility for enhancing health.
4. develop strategies to improve or maintain personal, family, and community health.
Note: The materials used in this lesson focus mostly on the impact that sun exposure has on people with light-to-medium skin color. While teaching, be sure to point out and reinforce that people with darker skin types must also be concerned about UV radiation exposure and use sunscreens regularly.
To find out what students already know about sunburns, tanning, and sunscreens, have them imagine that it is the 4th of July weekend and that they are planning to spend the day at the beach.
Ask questions like the following to help guide the discussion:
- When going to the beach, what will you need to take with you? Why?
- What's enjoyable about the beach? In what ways can it be dangerous?
- Does anyone sunbathe on a regular basis? Explain.
- Does anyone try to avoid exposure to the sun? Why?
- How concerned are you about being overexposed to the sun?
- What precautions should you take when you're exposed to the sun?
- How would you describe your skin type?
- Do people with darker complexions need protection from the sun? Why or why not?
- How often do you use sunscreen?
- How often or under what circumstances should sunscreen be used?
- What do you know about sunscreens? How do you think they work?
(Accept all reasonable answers. Encourage students to elaborate on their responses.)
Inform students that they will learn more about sun tanning, sunburns, and how sunscreens work in this lesson.
Divide the class into small groups and assign each group one of the four resources in this section. Have each group answer the questions on its resource and summarize the material for presentation to the class. Make sure students understand that they will be responsible for discussing and answering questions on the information covered in all the resources.
Before they begin, refer them to The Sun and Your Skin student esheet, which they will use to navigate the resources. Students can record the answers to the questions on the esheet on their You and Your Skin student sheet.
The first group should use their student esheet and go to the You and Your Skin resource, read it carefully, discuss the content, and take notes as they go. This resource will give them basic facts on the function, anatomy, protection, and care of their skin.
Basic questions group members will need to address include:
- What functions does your skin perform?
(Your skin protects your organs, muscles, and bones. It protects you from germ exposure, regulates body temperature, and keeps your body fluids from evaporating.)
- What is melanin? What does it determine?
(Melanin is a pigment in the skin which determines skin color. It also determines the amount a person will tan or burn when exposed to the sun.)
- Which part of your skin contains sweat glands?
(The dermis, or middle layer of skin, contains sweat glands.)
- What is the best way to treat cuts?
(Wash the area with warm soap and water. To protect from infection, apply an antibiotic cream or ointment and cover it with a sterile bandage.)
- Is it better to wash your face with your hands or a towel? Why?
(Using your hands is better because they are less abrasive to your skin than most towels.)
- What are some ways to keep you skin healthy?
(You can keep you skin healthy by eating right, drinking plenty of water, exercising regularly, getting plenty of sleep, avoiding tobacco, and using sunscreen regularly.)
The second group should go to and read The Tanning Taboo article, which explains the tanning culture, and how tanning and overexposure to the sun affect their skin. It also gives helpful tips on using sunscreens and sun-free tanning products.
The group will need to address these questions as part of its presentation:
- Why do you think people like having a tan?
(Answers will vary. Tans are perceived by many as being attractive, healthy, and youthful-looking.)
- How do UVA and UVB radiation differ? How do they affect the skin?
(UVA radiation penetrates the dermis, causing tanning. It is considered to cause aging skin. UVB radiation burns the epidermis, causing sunburns, and is often linked to skin cancer.)
- What happens to the skin as you tan?
(When UV rays hit your skin, melanocytes get stimulated, which triggers melanin production to protect your skin from the sun. The melanin acts like an umbrella for the skin's cells and gives people the brown tint that is a suntan.)
- How many skin types are there? What is your skin type?
(Answers will vary. There are six skin types, ranging from Type I (pale or fair skin) to Type VI (dark skin).)
- What are some symptoms of skin damage from UV radiation? What can happen in severe cases?
(Symptoms include wrinkles, brown age spots, blotchiness, and leathery, sagging skin.)
- Do young people have to worry about skin cancer? Why or why not?
(Yes, they do. Melanoma is the most severe type of skin cancer and has become the fastest growing form of cancer in terms of new cases, many involving people in their twenties.)
- What suggestions are given to help protect your skin from the sun's harmful rays?
(Answers will vary. It's important to use sunscreens with an SPF of 15 or more. They should block both UVA and UVB rays and be applied liberally every two to three hours depending on the amount of time you spend in the sun.)
- What does SPF stand for? What's important to know about it?
(It stands for Sun Protection Factor and should be at least 15 or higher.)
- Are sunlamps and tanning beds safe? Why or why not?
(The UVA light from a tanning bed is greater than that from the sun, which can significantly age your skin and increase your risk for skin cancer. Doctors cite the use of tanning salons as one reason why more young people are getting skin cancer.)
- How do self-tanning and airbrush tanning methods affect your skin?
(Also known as "tans in a bottle," self-tanners contain DHA which oxidizes on the outermost layers of your skin, giving you the look of a tan. Airbrush tanning involves spraying a DHA solution onto your body, giving you a painted-on tan.)
- Would you ever consider using these methods? Why or why not?
(Answers will vary.)
The third group should go to and read the Introduction to the Sunlight and Skin Damage article on the Merck website. There students will learn more about the dangers of UV radiation and sunburns. Inform students that they will not be responsible for the "Actinic Keratoses: Precancerous Growths" section at the bottom of the page.
Questions they will need to address in their presentations include:
- How can small amounts of UV light help the body?
(UV light in small amounts is beneficial, because it helps the body produce vitamin D.)
- In what ways do large amounts damage the body?
(Larger amounts of UV light damage DNA and alter the amounts and kinds of chemicals that the skin cells make. UV light also may break down folic acid, sometimes resulting in deficiency of that vitamin in fair-skinned people.)
- Which type of UV light is responsible for damage due to tanning, burning, and skin cancer?
(UVB is responsible for at least three quarters of the damaging effects of UV light, including tanning, burning, premature skin aging, wrinkling, and skin cancer.)
- Why is the amount of UV light reaching the earth's surface increasing?
(This increase is attributable to chemical reactions between ozone and chlorofluorocarbons—chemicals in refrigerants and spray can propellants—that are depleting the protective ozone layer, creating a thinner atmosphere with some holes.)
- What time of day is it the most intense?
(UV light is more intense between 10 a.m. and 3 p.m., in the summer, and at higher altitudes.)
- Do people with high melanin levels need to worry about sun exposure? Why or why not?
(Sensitivity to sunlight varies according to the amount of melanin in the skin. Darker-skinned people have more melanin and therefore greater protection against the sun's harmful effects, although they are still vulnerable.)
- What types of skin cancer can one get from excessive sun exposure?
(The more sun exposure a person has, the higher the risk of skin cancers, including squamous cell carcinoma, basal cell carcinoma, and malignant melanoma.)
The fourth group of students should read and discuss the Sunburn article on the Merck website. Have them overlook the bottom section, "Are Tans Healthy?" which has been addresssed in another resource.
Questions they will be required to address include:
- What are the symptoms of mild-to-severe sunburn?
(Mild cases result in painful, reddened skin. More severe cases may result in swelling and blisters, fever, chills, weakness, and even shock. People with pale skin may also experience peeling and itching days after a serious burn.)
- When do symptoms typically appear?
(Symptoms may begin as soon as one hour after exposure and typically reach their peak after one day.)
- What's the best way to protect yourself from the sun?
(The "best way" is to stay out of strong, direct sunlight on an ongoing basis.)
- What are some good and bad filters (or circumstances) for UV light?
(Good filters which block UV rays naturally include clothing and ordinary window glass. Bad filters which either do not block or further magnify UV light include water, clouds, fog, snow, and sand.)
- What are sunscreens?
(They are ointments or creams containing chemicals that protect the skin by filtering out UV light.)
- How do sunblocks differ from sunscreens?
(Sunscreens contain substances that absorb UV light, while sunblocks are thick, white ointments that contain physical barriers such as zinc oxide that block almost all sunlight from the skin.)
- Which SPF levels provide maximum protection from sun damage?
(SPFs rated at 30 and above provide the most protection.)
- What treatments help heal sunburned skin?
(Cold tap water compresses can soothe raw, hot areas, as can certain skin moisturizers. Nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid tablets, and antibiotic burn creams are often used to relieve the pain and inflammation of serious burns and blistering.)
Assess student understanding based on their answers to the questions above.
You also could have students write a persuasive letter to a friend offering advice either for or against the use of (a) sunscreens or (b) tanning salons.
Finish the lesson by having students answer the questions on the Sun & Skin Question and Response student, a series of multiple-choice questions that test students' basic knowledge of the main ideas and concepts presented in this lesson. (Answers to these questions can be found on the Sun & Skin Question and Response teacher sheet.)
You can extend the ideas in this lesson by leading students through these Science NetLinks lessons:
As an alternative to suntanning, students may be interested in How do sunless-tanning products work? from HowStuffWorks, which gives a thorough explanation about how sunless-tanning products work, and what to look for in these types of products.
To help reduce rising skin cancer rates, students may find it interesting to learn that schools in Australia are getting SunSmart and adopting policies to minimize sun exposure (e.g., providing sunscreen at school, requiring broad-brimmed hats, restricting outdoor activities, etc.).