| Introduction: |
There
are various methods of detecting UV radiation. One such method involves
a chemical substance embedded into plastic beads that will change color
when exposed to UV radiation. Students will use these indicator beads
to test the effectiveness of various sun screens and sun glasses in filtering
UV radiation. |
| National
Science Education Standards: |
Content Standard F, Grades
5-8:
Science in Personal and Social Perspectives
Personal and Community Health
|
| Concepts
& Principles: |
 Exposure
to solar radiation, including harmful UV, varies in intensity over the
course of a day.
Students can apply
scientific information to their daily decision making processes.
|
| Objectives: |
To
understand that solar radiation can be harmful.
To recognize the
time of day that sun exposure is more direct and intense.
To recognize preventive
measures that can be taken to reduce the risks associated
with exposure to solar radiation.
|
|
Cross-Curricular Connections:
|
History:
• How
other cultures and civilizations viewed the sun for example, Ra)
Economics:
• The
costs of UV protection and prevention
• The
health costs associated with UV damage
Sociology:
• High
risk lifestyles (occupations and recreation)
Math:
• Calculating
the UV Index
Arts:
• How
artists depict strong light and shadowing effects (chiaroscuro)
Language Arts:
• Mythology
associated with the sun
Science:
• Global
change research
• Cancer
research
|
| Process
Skills: |
Observing
Communicating
Predicting
Controlling Variables
Hypothesizing
Experimenting
|
| Lesson
Description: |
Students
will test various UV blocks, such as sunglasses and sunscreens (including
a range of SPF numbers), using UV beads. |
|
Materials:
|
In quantities appropriate
for class size:
UV Beads that turn white to purple. Available from:
Educational
Innovations, Inc.,
362
Main Avenue
Norwalk,
CT 06851
1-888-912-7474
http://www.teachersource.com
various sunscreens with SPF 5, 10, 15, 20
sunglasses (cheap dimestore type and a pair with UV protection)
polaroid camera (optional)
plastic wrap
string
student journals |
| Suggested
Time Frame: |
One
45-minute session. |
|
Procedure:
|
- Distribute 30 UV beads
to each cooperative group.
- Ask each group to take
the beads outside and observe what happens.
- Return to the classroom
and let the beads return to a white color.
- Share conclusions.
- Students should design
and carry out investigations using materials such as sunscreens or
sunglasses that claim to shield out UV radiation.
|
|
Suggested Discussion
Questions:
|
Besides
the specially made beads used in this experiment, what else can be used
as a UV detector?
Why does your skin
turn dark after exposure to UV?
Visit a nursery and
locate a number of plants with instructions to grow in indirect light.
Why would a plant grow better in indirect sunlight than direct sunlight?
If you have a yard or patio, where would you place such a plant? Why?
Why not in other locations?
Can you explain how
it is possible to get a sunburn on a cloudy day? Can you design a test
to measure UV on a cloudy day?
UV radiation is used
to sterilize instruments and even to sterilize water. How does UV act
as a sterilizing agent?
How could UV beads
be used to warn people about excessive UV exposure?
|
| Further
Investigations: |
Demonstrate
photo-oxidation of various materials such as plastics, auto paint etc.
Students can use light
meters to test the intensity of light in direct sun, in the shade, or
over a reflective surface, such as sand or concrete.
Investigate industrial
products that are used to prevent photo damage to signs and awnings. |
| Career
Opportunities: |
Dermatologist
Ophthalmologist
Resort Worker
Landscape Architect
Meteorologist
Environmental Specialist
Commercial Fisherman
Forester |
|
Assessment Procedures:
|
Collect
the sunburn index and weather map from a newspaper over a period of
several days. (You will need a range of high, moderate, and low). Have
students record sun burn indices and cloud cover. Allow students to
offer explanations for this correlation.
A
family is planning a vacation at the beach, even though everyone got
sunburned on the first day of last year’s vacation! They want to
spend as much time
as possible swimming, collecting seashells, or just relaxing on the
beach. The family also wants to see several movies, visit the local
museums, and shop at the nearby outlet mall. Plan this family’s
schedule so that they can spend as much time on the beach as is safely
possible and also do the other things they wish to do. Remember to consider
the impact of direct and prolonged exposure as you devise the family’s
activity schedule.
|
