328

Section

5 The Skin

ObjectivesAfter this lesson, students will be able toD.1.5.1 Describe the functions and the structures of skin.D.1.5.2 Identify habits that can help keep skin healthy.

Target Reading SkillIdentifying Main Ideas Explain that identifying main ideas and details helps students sort the facts from the information into groups. Each group can have a main topic, subtopics, and details.

AnswersSample details:The skin forms a barrier against disease-causing microorganisms and harmful substances, and prevents the loss of important fluids; the skin helps the body maintain a steady temperature; the skin helps to eliminate wastes through perspiration; the skin contains nerves that gather information about the environment; skin cells produce vitamin D that helps your body absorb calcium.

Teaching Resources

• Transparency D9

Preteach

Build Background KnowledgeWhat Skin DoesHave students look at the skin on their arms and hands. Ask them to speculate about what they think their skin does. (Sample answers: It protects body tissues underneath, keeps bacteria out of the body, produces sweat, and provides feeling through the sense of touch.)

L1

Skills Focus Inferring

Materials hand lens, plastic gloves

Time 15 minutes

Tips Ask students to predict what structures they expect to see on the surface of their skin.

Expected Outcome Students will observe perspiration, hairs on the back of the hands, and ridges.

Think It Over After students have worn the plastic glove, moisture covering the skin’s surface will be noticeable. Perspiration is one of the functions of the skin.

328 ◆

5 The Skin

What Can You Observe About Skin?1. Using a hand lens, examine the skin on your hand. Look for

pores and hairs on both the palm and back of your hand.2. Place a plastic glove on your hand. After

five minutes, remove the glove. Then, examine the skin on your hand with the hand lens.

Think It OverInferring Compare your hand before and after wearing the glove. What happened to the skin when you wore the glove? Why did this happen?

Reading PreviewKey Concepts• What are the functions and the

structures of skin?

• What habits can help keep your skin healthy?

Key Terms• epidermis • melanin• dermis • pore • follicle• cancer

Target Reading SkillIdentifying Main Ideas As you read the section titled The Body's Tough Covering, write the main idea—the biggest or most important idea—in a graphic organizer like the one below. Then, write five supporting details. The supporting details give examples of the main idea.

Here’s a question for you: What’s the largest organ in thehuman body? If your answer is the skin, you are right! If anadult’s skin were stretched out flat, it would cover an arealarger than 1.5 square meters—about the size of a mattress ona twin bed. You may think of the skin as nothing more than acovering that separates the inside of the body from the outsideenvironment. If so, you’ll be surprised to learn about the manyimportant roles that the skin plays.

The Body’s Tough CoveringThe skin performs several major functions in the body. Theskin covers and protects the body from injury, infection, andwater loss. The skin also helps regulate body temperature,eliminate wastes, gather information about the environ-ment, and produce vitamin D.

Protecting the Body The skin protects the body by form-ing a barrier that keeps disease-causing microorganisms andharmful substances outside the body. In addition, the skinhelps keep important substances inside the body. Like plasticwrap that keeps food from drying out, the skin prevents theloss of important fluids such as water.

Detail Detail Detail

Main Idea

The skin has several importantfunctions.

L1

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Differentiated Instruction

Instruct

The Body’s Tough Covering

Teach Key ConceptsThe Functions of SkinFocus Have students look at the other people in the class. Ask: What is the most obvious function of skin? (To cover and protect the body)

Teach Explain that the skin keeps out harmful microorganisms and substances and keeps in fluids, but skin has other functions, too. Ask: How does skin regulate temperature? (When you are too warm, blood vessels in the skin enlarge to allow heat to move out of your body. The evaporation of perspiration cools the skin.) How is waste eliminated by the skin? (Through perspiration) What information can you gather from the environment through your skin? (Pressure, pain, and temperature) How does your skin help you to have healthy bones? (Some skin cells produce vitamin D that helps your digestive system to absorb calcium, which is needed for strong bones.)

Apply Ask students to identify how each function of skin helps the body maintain homeostasis—for example, helping to maintain water balance. learning modality: verbal

Independent PracticeTeaching Resources

• Guided Reading and Study Worksheet: The Skin

Student Edition on Audio CD

L1

L2

Special NeedsDemonstrating Skin Functions Gently squeeze students’ hands, and explain that the nerves in skin help them to feel the pressure. Rub a piece of ice on their skin to demonstrate that the skin senses temperature. Ask: What happens to your skin when you feel cold? (You get goose bumps.) Have students dip a finger into a cup of water, then hold the finger in the air.

L1 Ask: How does your finger feel? (Cool) Explain that this is like what happens when people sweat. The sweat, like the water, removes heat from your body and makes you feel cooler. learning modality: kinesthetic

Monitor Progress L2

Skills Check Have students create concept maps of the skin’s functions.

AnswersFigure 18 As perspiration evaporates from the skin, heat moves from the body into the environment.

Nerves in skin provide information about pressure, pain, and temperature.

Chapter 8 ◆ 329

Maintaining Temperature Another function of the skin isto help the body maintain a steady temperature. Many bloodvessels run throughout the skin. When you become too warm,these blood vessels enlarge and the amount of blood that flowsthrough them increases. These changes allow heat to movefrom your body into the outside environment. In addition,sweat glands in the skin respond to excess heat by producingperspiration. As perspiration evaporates from your skin, yourskin is cooled.

Eliminating Wastes Perspiration contains dissolved wastematerials that come from the breakdown of chemicals duringcellular processes. Thus, your skin is also helping to eliminatewastes whenever you perspire. For example, some of the wastesthat come from the breakdown of proteins are eliminated inperspiration.

Gathering Information The skin also gathers informationabout the environment. To understand how the skin does this,place your fingertips on the skin of your arm and press downfirmly. Then lightly pinch yourself. You have just tested someof the nerves in your skin. The nerves in skin provide informa-tion about such things as pressure, pain, and temperature. Painmessages are important because they warn you that somethingin your surroundings may have injured you.

Producing Vitamin D Lastly, some of the skin cells pro-duce vitamin D in the presence of sunlight. Vitamin D isimportant for healthy bones because it helps the cells in yourdigestive system to absorb the calcium in your food. Your skincells need only a few minutes of sunlight to produce all thevitamin D you need in a day.

How does your skin gather information about the environment?

FIGURE 18Eliminating WastesSweat glands in the skin produce perspiration, which leaves the body through pores. The inset photo shows beads of sweat on skin.Relating Cause and Effect Inaddition to eliminating wastes, what is another important function of perspiration?

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Differentiated Instruction

330

Help Students ReadSQ3R Have students survey the diagrams, photos, and graph in this section, and write a short explanation of each. Then have them write questions, read the section, recite their questions, and give the answers in their own words. Tell students to review the section by writing their answers, and then answer the Key Concepts questions on the first page of the section. For more information on SQ3R, refer to the Content Refresher.

The Epidermis

Teach Key ConceptsThe First Layer of SkinFocus Tell students that the epidermis is the layer of skin you can see.

Teach Refer students to Figure 19. Ask: What is the epidermis made of? (A layer of dead cells) How do these dead cells protect you? (The dead cells on your fingertips cushion the fingertips, shedding of dead cells carries away bacteria, and some cells produce hard fingernails.)

Apply Ask: What is the advantage of having dead cells make up the outer layer of skin instead of living tissue? (Living tissue has nerves and blood vessels. You would feel pain more easily from cuts and pressure. You would bleed more easily.) learning modality: verbal

Teaching Resources

• Transparency D10

L1

English Learners/BeginningVocabulary: Word KnowledgeContrast the meanings of dermis and epidermis. Point out that dermis means “skin” and the prefix epi means “outside.” Ask students to relate these terms. (The epidermis is on the outside of the dermis.) learning modality: verbal

L1 English Learners/IntermediateVocabulary: Science Glossary Pronounce the key terms epidermis, dermis, pores, and follicles as you point to them in Figure 19. Have students write the definition of each of those terms in their science glossaries, and draw and label their own diagrams of the structures. learning modality: verbal

L2

330 ◆

The EpidermisThe skin is organized into two main layers, the epidermisand the dermis. The epidermis is the outer layer of the skin. Inmost places, the epidermis is thinner than the dermis. The epi-dermis does not have nerves or blood vessels. This is why youusually don’t feel pain from very shallow scratches, and whyshallow scratches do not bleed.

Epidermis Structure Like all cells, the cells in the epider-mis have a life cycle. Each epidermal cell begins life deep in theepidermis, where cells divide to form new cells. The new cellsmature and move upward in the epidermis as new cells formbeneath them. After about two weeks, the cells die and becomepart of the epidermal surface layer. Under a microscope, thissurface layer of dead cells resembles flat bags laid on top of oneanother. Cells remain in this layer for about two weeks. Then,they are shed and replaced by the dead cells below.

Epidermis Function In some ways, the cells of the epider-mis are more valuable dead than alive. Most of the protectionprovided by the skin is due to the layer of dead cells on the sur-face. The thick layer of dead cells on your fingertips, for exam-ple, protects and cushions your fingertips. Also, the sheddingof dead cells carries away bacteria and other substances thatsettle on the skin. Every time you rub your hands together, youlose thousands of dead skin cells and any bacteria on them.

PoreHair Oil gland

Blood vessels

Nerve

Epidermis

Dermis

Sweat gland

Sweatdroplet

Fat

Hair follicle

FIGURE 19

The SkinThe skin is made of two main layers. The top layer is called the epidermis. The bottom layer is called the dermis.Interpreting Diagrams In which layer of the skin do you find blood vessels?

L1

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The Dermis

Teach Key ConceptsThe Second Layer of SkinFocus Refer students to Figure 19.

Teach Ask students to note differences between the epidermis and the dermis. (The dermis is thicker. It has blood vessels, nerves, hair follicles, sweat glands, and fat.) What are the functions of the dermis? (The fat pads internal organs and helps keep heat in the body. Sweat glands produce perspiration. Oil helps moisten the skin.)

Apply Ask: How does the dermis help regulate temperature when you are hot? (It contains blood vessels that widen to help move heat from the body.) Ask students to infer what happens to blood vessels in the dermis when a person is cold. (They narrow to conserve heat.) learning modality: verbal

Use Visuals: Figure 19Epidermis and DermisFocus Ask students to identify the openings in the epidermis. (Pores and openings of hair follicles)

Teach Ask: What are the pores connected to? (Sweat glands) Where is oil produced? (In glands around the hair) Call students’ attention to the inset of the hair. Ask: What are the scalelike structures? (Dead epidermal cells)

Apply Ask students to infer the relationship between the hairs and the nerves in the dermis. (When something touches or blows against the hairs, the nerves pick up the sensation.) learning modality: visual

L2

L1

Skills Focus Measuring

Materials 2 thermometers, wet cotton ball, piece of cardboard

Time 15 minutes

TipsCAUTION: Advise students to use care when handling the thermometers.

Have students note the temperatures on both thermometers before beginning.

Expected Outcome The thermometer wrapped in wet cotton has a lower temperature after it is fanned. When skin is moist, sweat evaporates, removing body heat and lowering the body temperature.

Extend Ask students why they might put on a heavy sweatshirt after vigorous physical activity. (To keep from getting chilled when sweat evaporates) learning modality: logical/mathematical

Monitor Progress L2

Writing Have students write paragraphs that compare and contrast the structure and function of the dermis and epidermis.

AnswersFigure 19 The dermis

They are the openingsthrough which perspiration

from sweat glands in the dermis reaches the skin’s surface.

Chapter 8 ◆ 331

Hair follicle

Sweaty SkinThis activity illustrates one of the skin’s functions.

1. Wrap a wet cotton ball around the bulb

of one thermometer. Place a second thermometer next to the first one.

2. After two minutes, record the temperature reading on each thermometer.

3. Using a piece of card–board, fan both of the thermometers for several minutes. The cardboard should be at least 10 cm from the thermometers. Record the temperatures.

Measuring Which of the thermometers had a lower temperature after Step 3? How does this activity relate to the role of skin in regulat-ing body temperature?

Some cells in the inner layer of the epidermis help to pro-tect the body, too. On your fingers, for example, some cellsproduce hard fingernails, which protect the fingertips frominjury and help you scratch and pick up objects.

Other cells deep in the epidermis produce melanin, a pig-ment, or colored substance, that gives skin its color. The moremelanin in your skin, the darker it is. Exposure to sunlightstimulates the skin to make more melanin. Melanin produc-tion helps to protect the skin from burning.

The DermisThe dermis is the inner layer of the skin. Find the dermis inFigure 19. Notice that it is located below the epidermis andabove a layer of fat. This fat layer pads the internal organs andhelps keep heat in the body.

The dermis contains nerves and blood vessels. The dermisalso contains sweat glands, hairs, and oil glands. Sweat glandsproduce perspiration, which reaches the surface through open-ings called pores. Strands of hair grow within the dermis instructures called follicles (FAHL ih kulz). The hair that you seeabove the skin’s surface is made up of dead cells. Oil producedin glands around the hair follicles help to waterproof the hair.In addition, oil that reaches the surface of the skin helps tokeep the skin moist.

What is the function of pores in the skin?

L2

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Caring for Your Skin

For:

Links on the skin

Visit:

www.SciLinks.org

Web Code:

scn-0415

Download a worksheet that will guide students’ review of Internet resources on the skin.

Teach Key Concepts

Habits to Keep Skin Healthy

Focus

Tell students that acne is the most common skin problem for teens.

Teach

Ask:

What is a healthful habit to help control acne?

(Keep your face clean.)

What are other habits to care for your skin?

(Eat a well-balanced diet, drink plenty of water, and protect your skin from sun damage.)

Apply

Tell students that people with acne should wash their face twice a day with a mild cleanser. More frequent washing or scrubbing with strong soap or scrub pads can make acne worse.

learning modality: verbal

Math Skills

Making and interpreting graphs

Focus

Remind students that wearing sunscreen is one way to reduce the risk of skin cancer.

Teach

Tell students that the skin’s relative resistance to sunburn, as well as the strength of sunscreen used, affects how long you can safely stay in the sun. However, limiting sun exposure is recommended for everyone as the best method of preventing overexposure.

Answers

1.

The height of each bar represents the amount of time that person can spend in the sun before burning.

2.

20 minutes; 80 minutes; 5 hours

3.

Person C would need to use SPF 15 sunscreen because SPF 4 would protect the individual for only four hours.

4.

SPF 15 is 3.75 times more effective at preventing sunburn. Calculations: 2.5 hours compared to 40 minutes, or 150 minutes/40 minutes = 3.75; 5 hours

L2

compared to 80 minutes, or 300 minutes/80 minutes = 3.75

5.

It stands for the level of protection against sunburn—the higher the level is, the greater the protection. SPF 4 means a person can safely stay four times as long in the sun; SPF 15—15 times as long.

332 ◆

Caring for Your SkinBecause your skin has so many vital functions, taking care of itis important. Three simple habits can help you keep your skinhealthy. Eat a healthful diet. Keep your skin clean and dry.Limit your exposure to the sun.

Healthful Diet Your skin is always active. Eating a well-balanced diet provides the energy and raw materials needed forthe growth and replacement of hair, nails, and skin cells. Inaddition to what you eat, a healthful diet also includes drink-ing plenty of water. That way, you can replace the water lost inperspiration.

Keeping Skin Clean When you wash your skin with mildsoap, you get rid of dirt and harmful bacteria. Washing yourskin also helps to control oiliness.

Good washing habits are particularly important duringthe teenage years when oil glands are more active. Whenglands become clogged with oil, the blackheads and white-heads of acne can form. If acne becomes infected by skin bac-teria, your doctor may prescribe an antibiotic to help controlthe infection.

For: Links on the skinVisit: www.SciLinks.orgWeb Code: scn-0415

Sunscreen RatingsThe graph shows how sunscreens with different sun protection factor (SPF) ratings extend the time three people can stay in the sun without beginning to get a sunburn.

1. Reading Graphs What does the height of each bar in the graph represent?

2. Interpreting Data How long can Person B stay in the sun without sunscreen before starting to burn? With a sunscreen of SPF 4? SPF 15?

3. Inferring Suppose that Person C was planning to attend an all-day picnic. Which sunscreen should Person C apply? Use data to support your answer.

4. Calculating Which is more effective at preventing sunburn—a sunscreen with SPF 4 or one with SPF 15? How much more effective is it? Show your work.

5. Drawing Conclusions What does the number in the SPF rating stand for? (Hint:Note the length of time each person can stay in the sun without sunscreen and compare this value to the length of time each can stay in the sun using SPF 4. Then, do the same for SPF 15.)

Tim

e B

efo

re B

urn

ing

(h

ou

rs)

A B C

15

10

5

0

Sunscreens and Sunburn

Person

No sunscreenSPF 4SPF 15

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L2

Monitor Progress L2

AnswersFigure 20 Wearing sunscreen and avoiding exposure to the sun between 10 A.M. and 2 P.M.

Damage to skin cells, cancer, and wrinkled, leathery skin.

Assess

Reviewing Key Concepts1. a. The skin protects the body from injury, infection, and water loss; helps regulate body temperature; eliminates waste; gathers information about the environment; and produces vitamin D. b. The epidermis consists of a layer of dead cells that protect the inner parts of the skin. The dermis contains a fat layer that helps keep in heat and sweat glands that help cool the body. c. If pores in the dermis become blocked the blackheads and whiteheads of acne can form.2. a. Accept any three: Eat properly, drink enough water, limit exposure to the sun, and keep skin clean and dry. b. It is important to use sunscreen when outdoors because unprotected skin can burn. Also, repeated exposure to sunlight can damage skin cells, causing them to become cancerous. c. Sample answer: Washing the skin too much may cause dryness and remove dead skin cells that are necessary to protect the skin.

ReteachUse Figure 19 to review how each structure relates to the function of the skin.

Performance AssessmentWriting Have students develop a pamphlet explaining to other teens how to take care of their skin.

Teaching Resources

• Section Summary: The Skin• Review and Reinforce: The Skin• Enrich: The Skin

L1

Protection From the Sun Before students perform this activity, have them identify ways that people protect themselves from the sun. Encourage students to include items such as hats, sunglasses, and beach umbrellas.

Chapter 8 ◆ 333

Limiting Sun Exposure It is important toprotect your skin from the harmful effects ofthe sun. Repeated exposure to sunlight candamage skin cells, and possibly lead to skin can-cer. Cancer is a disease in which some cells inthe body divide uncontrollably. In addition,repeated exposure to the sun can cause the skinto become leathery and wrinkled.

There are many things you can do to protectyour skin from damage by the sun. When youare outdoors, always wear a hat, sunglasses, anduse a sunscreen on exposed skin. Choose cloth-ing made of tightly woven fabrics for the great-est protection. In addition, avoid exposure tothe sun between the hours of 10 A.M. and 4 P.M.That is the time when sunlight is the strongest.

What health problems can result from repeated sun exposure?

Section 5 Assessment

Target Reading Skill Identifying Main Ideas Use your graphic organizer to help you answer Question 1 below.

Reviewing Key Concepts1. a. Listing What are five important functions of the skin?

b. Identifying How does the epidermis protect the body? What structure in the dermis helps to maintain body temperature?

c. Inferring What could happen if the pores in your dermis become blocked?

2. a. Identifying What are three things you can do to keep your skin healthy?

b. Explaining Why is it important to use sunscreen to protect your skin when outside?

c. Making Judgments Do you think it is possible to wash your skin too much and damage it as a result? Why or why not?

FIGURE 20Skin ProtectionThis person is wearing a hat to protect his skin from the sun.Applying Concepts What other behaviors can provide protection from the sun?

5

Protection From the Sun With a family member, look for products in your home that provide protec-tion from the sun. You may also want to visit a store that sells these products. Make a list of the prod-ucts and place them in categories, such as sunblocks, clothing, eye protectors, and other forms of pro-tection. Explain to your family member why it is important to use such products.

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Sun Safety

Prepare for InquiryKey ConceptThe higher a product’s SPF rating, the better it protects individuals from the sun.

Skills ObjectivesAfter this lab, students will be able to• observe the effectiveness of different levels

of sun protection• predict which sunscreen provides more

protection• interpret data on which fabrics protect

against sun exposure• draw conclusions about which fabric

provided the most protection

Prep Time 20 minutes

Class Time 45 minutes, follow-up 20 minutes

Advance Planning• Obtain photosensitive paper from science

supply houses, or a toy or craft store.• Collect fabric or have students bring in

scraps of fabric. Choose fabrics commonly worn by students, such as T-shirt material and denim.

• Before the activity, test a strip of photosensitive paper in the window of your classroom, if present, to determine whether UV rays pass through that particular glass.

SafetyRemind students to be careful when using scissors. Caution

them not to get any sunscreen into their eyes or mouths. Advise them to wash their hands after the lab. If sunlamps are used, be sure students do not look at the light source and if possible, provide UV-protective goggles. Review the safety guidelines in Appendix A.

Teaching Resources

• Lab Worksheet: Sun SafetyGuide InquiryIntroduce the Procedure • Demonstrate how to cut the

photosensitive and construction paper strips and staple them in place in the plastic bag. Demonstrate the technique for coating the bag with sunscreen.

• Check that students understand that the white construction paper allows them to control the experiment and compare their results. Ask: What are some other controls? (Using the same amount of sunscreen and making sure the strips are exposed to direct sunlight)

334 ◆

Sun Safety

ProblemHow well do different materials protect the skin from the sun?

Skills Focusobserving, predicting, interpreting data, drawing conclusions

Materials• scissors• photosensitive paper• metric ruler• white construction paper• stapler• pencil• resealable plastic bag• plastic knife• 2 sunscreens with SPF ratings of 4 and 30• staple remover• 3 different fabrics

ProcedurePART 1 Sunscreen Protection

1. Read over the procedure for Part 1. Then, write a prediction about how well each of the sunscreens will protect against the sun.

2. Use scissors to cut two strips of photosensi-tive paper that measure 5 cm by 15 cm.

3. Divide each strip into thirds by drawing lines across the strips.

4. Cover one third of each strip with a square of white construction paper. Staple each square down.

5. Use a pencil to write the lower SPF rating on the back of the first strip. Write the other SPF rating on the back of the second strip.

6. Place the two strips side by side in a plastic bag. Seal the bag, then staple through the white squares to hold the strips in place.

7. With a plastic knife, spread a thin layer of each sunscreen on the bag over the bottom square of its labeled strip. This is shown in the photo above. Make certain each strip has the same thickness of sunscreen. Be sure not to spread sunscreen over the middle squares.

8. Place the strips in sunlight until the color of the middle squares stops changing. Make sure the bag is sunscreen-side up when you place it in the sunlight.

9. Remove the staples from the bag, and then take out the strips. Take off the construction paper. Rinse the strips for one minute in cold water, then dry them flat.

10. Observe all the squares. Then, record your observations.

L2

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•

Place the strips where they will receive direct sunlight. You could use an artificial source of ultraviolet light such as a sunlamp.

Expected Outcome

The sunscreens with the highest SPF and the materials with the tightest weave provide the most protection.

Analyze and Conclude

1.

Yes; sections not covered by sunscreen changed color drastically. The covered sections changed color slightly or not at all.

2.

The sunscreen with SPF 30 provided more protection. Yes, if students predicted this result. A sunscreen with an SPF of 15 would provide more protection than SPF 4 but less protection than SPF 30.

3.

Yes; the sections covered by fabric did not change color as much as the uncovered areas.

4.

The heaviest or most tightly woven fabric, such as denim, provided the most protection. Thin fabrics, such as T-shirt material or light gauze, provided the least protection. Sample answer: My predictions matched the results.

5.

Sample answer: Wear sunscreen, limit exposure to the sun, and wear clothing that blocks the sun. The pamphlet should include choosing a sunscreen with a high SPF rating and wearing clothing that blocks the sun. (You may want to share with students that lightweight clothing specially made to block UV rays is available.)

Extend Inquiry

More to Explore

Students’ designs should include placing one strip of photosensitive paper in direct sunlight and one on an inside window sill or under a piece of window glass. Check that students control variables such as the angle and amount of sunlight received.

Chapter 8 ◆ 335

PART 2 Fabric Protection

11. Your teacher will provide three fabric pieces of different thicknesses.

12. Based on the procedure in Part 1, design an experiment to test how effective the three fabrics are in protecting against the sun. Write a prediction about which fabric you think will be most effective, next most effec-tive, and least effective.

13. Obtain your teacher’s approval before carry-ing out your experiment. Record all of your observations.

Analyze and Conclude1. Observing Did the sunscreens protect

against sun exposure? How do you know?

2. Predicting Which sunscreen provided more protection? Was your prediction correct? How would you predict a sunscreen with an SPF of 15 would compare to the sunscreens you tested?

3. Interpreting Data Did the fabrics protect against sun exposure? How do you know?

4. Drawing Conclusions Which of the fabrics provided the most protection? The least pro-tection? How did your results compare with your predictions?

5. Communicating What advice would you give people about protecting their skin from the sun? Create a pamphlet in which you address this question by comparing the different sun-screens and fabrics you tested.

More to ExploreDesign another experiment, this time to find out whether ordinary window glass protects skin against sun exposure. Obtain your teacher’s per-mission before carrying out your investigation.

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