Printer Friendly: pdf version
In the 1980's scientists discovered that a hole in the ozone occurs over Antarctica in the austral summer. The ozone shield screens out most of the sun's harmful UV rays. Without the shield, humans are much more susceptible to sunburn, UV radiation, and, thereby, cancer. In this activity, students will learn about the dangers of UV radiation and why the study of the ozone hole over Antarctica is so important.
How UV radiation affects your skin type and why scientists are monitoring the hole in the ozone over Antarctica
Cincinnati Country Day School
6905 Given Rd.
Cincinnati, OH 45243
frenchj at countryday.net
In this lesson, students will use a UV detection meter to record the daily UV penetration by the sun. They will use this data to discover their own susceptibility to a sunburn for each day, based on their skin type. Students will then research the cause of sunburns, the ozone layer, and the hole in the ozone to learn how the ozone layer forms, how it protects us from UV radiation, and why there is a hole in the ozone layer over Antarctica in the austral summer.
Grades 5-8 environmental science, chemistry, and health. Applicable to high school students by scaling the lesson up so that a deeper understanding of the chemistry of ozone production and depletion is studied. Applicable to K-4 by deleting the chemistry portion of the lesson.
Content Standard B: Physical Science
All students should develop an understanding of properties and changes of properties of matter.
Content Standard D: Earth and Space Science
All students should develop an understanding of: structure of the earth system and Earth in the solar system
Content Standard F: Science in Personal and Social
All students should develop an understanding of personal health and natural hazards
Make enough copies of the Daily UV chart for the whole class
Sunsor UV detection meter; available at:
Sunsor UV exposure guide (accompanies meter; may also be accessed from the website above) Sunsor skin type guide (accompanies meter; may also be accessed from the website above)
UV detection beads from: Educational Innovations, 1-888-912-7474 (five per student)
Pipe cleaners (one per student)
Daily UV Chart
One pair of sunglasses without UV protection
One pair of sunglasses with UV protection
3 one-hour classes plus 10-mins each day for a month to collect data
1. Give each student one pipe cleaner and 5 UV detection beads. They are to thread the beads onto the pipe cleaner and then twist the ends of the pipe cleaner together to form a bracelet.
2. Send the class outside on a sunny day and observe what happens to the beads (they turn from white to an assortment of colors). Bring them inside and have them observe the beads again (after a few minutes, the beads will turn back to white).
3. Elicit from the class why they think this happened. If no one guesses that it has something to do with the sun, then provide the answer. Ask them if they think it would happen on a cloudy day and then try it again to see (if the day is not too overcast, beads will turn color again because some UV rays can still penetrate through the clouds).
4. Explain that these beads are ultraviolet detection beads and they are specially made to change color in the presence of ultraviolet radiation. Ask if anyone knows what UV radiation is, and if not, explain. Further explain that UV rays are the sector of rays that cause sunburn and skin cancer and because of that they are dangerous to us. Explain that the class will be recording UV radiation for a month and figuring out how that radiation directly affects them. Let them keep the beads and notice the color changes over the course of a week.
5. Give each student a Determine Your Skin Type chart and have them decide what their own skin type is based on the skin type definitions on the chart (younger students may need help with this).
6. Give each student a Daily UV Chart to record their results.
7. Show the UV detection meter and demonstrate how to use it outside. Let one student read the measurement. Have the class record the measurement on their chart. Decide as a class what the sky looks like that day ( sunny, partly cloudy, mostly cloudy, overcast), and record it on the chart.
8. Direct the class to look at the graph that is applicable to their skin type. Have them decide what their skin reaction will be after 1, 3, and 5 hours in the sun, and write these reactions on their chart.
9. Tell the class you have two pairs of sunglasses. Hold the pair without UV protection between the sun and the meter. Have a student read the UV measurement. Do the same with the pair that has UV protection and compare the results. Ask the class if they can think of a reason that they would get different readings. Explain that one pair had UV protection and one didn’t.
Go on to procedure #10 while continuing to record the UV data for a month. After one month, have the class look at their data, and answer the following questions:
What is the highest UV reading you recorded? The lowest?
Can you make a correlation between the amount of cloud cover and
the UV measurement? (Students should be able to see a general
trend of higher UV measurements on days with little cloud cover
and lower measurements on days with a lot of cloud cover.)
10. While the class continues to record their UV measurements (let the students take turns going outside for the reading), they will access NASA Educational Resource website on UV radiation (or teacher may provide a hard copy): http://www.nas.nasa.gov/About/Education/Ozone/radiation.html
Answer the following questions:
What are the three factors that affect the amount of radiation at a particular location?
What are the health effects of UV radiation?
11. Students access the National Science Foundation
Polar Programs UV Monitoring Network website on the UV measurements
taken at the South Pole (or teacher may provide a hard copy):
a. Students study the graph to find a correlation
between the highs in the UV index and the time of year. UV highs
are associated with austral summer months (September-February).
b. Elicit predictions from the class as to why they think the high UV measurements are in the austral summer months. Ask if anyone knows what ozone is. Tell the class that ozone is a layer of O3 molecules in the stratosphere that blocks most of the UV rays from hitting the earth.
c. Direct students to access the National Science Foundation Polar Programs UV Monitoring Network “Ozone” website:
Answer the following questions: What is ozone? How is it formed?
Review their answers and fill in any gaps using Fig. 1a (attached).
12. Direct students back to the previous website
and click on “ozone
hole” under the heading “How is it distributed over
and ask them to find out where the hole in the ozone is and how ozone is destroyed. Review their answers and fill in any gaps using Fig. 1b (attached). Explain why there is a hole in the ozone over Antarctica (refer to University of Cambridge website for a concise explanation).
13. Draw the class’s attention back to the graph in procedure #10, and explain that during the austral summer, the ozone may be depleted by as much as 50%. Ask them to explain why there is a seasonal difference in the UV readings at the South Pole.
14. Students will write a one page report to
explain the following concepts: What is UV radiation?
What is your skin type and how is effected by the amount of time spent in the sun?
What is ozone?
Why is ozone important to us?
How is ozone formed?
How is it destroyed?
What is meant by the hole in the ozone?
Where is the hole and when does it develop?
Why does the hole develop at a particular time of year?
Evaluation may be based on:
1. the accuracy and completion of the Daily UV chart
2. the ability to scan for information on the Internet
3. level of understanding of the basic concepts as demonstrated by the student's report
Ozone (O3) is produced in the earth’s stratosphere and forms a protective shield against ultraviolet (UV) radiation from the sun. The shield screens out most of the harmful UV rays, which cause cancer. This ozone is formed by the sun’s rays hitting and splitting up oxygen molecules (O2) into separate oxygen atoms. These atoms then join with other O2 molecules to form the protective ozone (O3). See figure 1a.
It was discovered in the mid 1980’s, that a hole in the ozone occurs over Antarctica in the austral summer. International concern led scientists to study the hole to learn why it happens and what can be done about it. In simple terms, the breakdown in ozone is caused by emissions from factories of chlorofluorocarbons (CFC’s). When the sun’s rays strike CFC’s, a chlorine atom breaks away and strikes an O3 molecule, which in turn splits into one ClO and one O2 molecule, which results in an overall loss of O3 or ozone (fig.1b).
|Skin Type||Hair/Eyes/Skin||Reaction to Sun|
Very light skin
Medium to olive skin
Dark olive-light brown skin
Dark brown tan
Very dark skin
|Insensitive to sun
Does not burn
Modified from: http://ourworld.compuserve.com/homepages/sunsor
|Date||UV Measurement||Cloud Cover||Skin Reaction:
Cloud Cover: sunny, partly cloudy, mostly cloudy, overcast
Environmental Protection Agency: Ozone Depletion
National Atmospheric and Space Administration:
National Science Foundation Polar Program UV Monitoring Network
University of Cambridge: Center for Atmospheric Science