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The learning
activities in this Lesson will help students prepare to complete the GE
Lighting Audit for their school or home as they learn how we measure various
properties of lighting and choose the best light bulb for a given lighting
need.
This Lesson
comprises three learning activities.
What's
Watt: Measuring Light is a Read About that presents the definitions
of various terms used in the measurement of light intensity, illuminance,
and the energy consumed by light bulbs.
In
Inverse Square Law, a Hands-on activity that extends the learning
in What's Watt, students
work with the mathematics of illuminance to understand that the amount
of light that falls on a surface is geometrically related to its distance
from the light source.
In How
to Read a Light Bulb Package, a Hands-on activity, students compare
information about lumens, wattage, and longevity for three different types
of light bulbs.
- to define
watt as energy usage.
- about
illuminance.
- how candlepower,
candela, and lumens are terms related to light intensity.
- the difference
between light bulb wattage and lumens.
The
chart below suggests options for incorporating the activities into your
schedule.
Activity
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Class
Periods Needed to Complete
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Teaching
Approaches to Consider
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Features
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1.
What's Watt: Measuring Light
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one
or two
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Independent
reading
Guided
reading
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Before
Reading, During Reading, Vocabulary, and After Reading questions
Sidebar:
The Photometer
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Teaching
Ideas
- As
a homework assignment, ask students to list five different places
in their homes where incandescent light bulbs are used. These
may include a desk lamp, inside a refrigerator, a hallway, a closet,
over a bathroom mirror, etc. Have them record the wattage of the
light bulb used in each place. Challenge them to compute how many
watts of the energy consumed actually results in visible light
and how many result in heat.
- Have
students read aloud their responses to the After Reading question
about new things they have learned from reading this article.
Further discuss any misconceptions or faulty understandings they
may have.
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Activity
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Class
Periods Needed to Complete
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Teaching
Approaches to Consider
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Features
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2.
Inverse Square Law
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one
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Teacher
demonstration
Small
group work in class
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Animation:
Inverse Square Law
Sidebar:
Why is the Inverse Square Law Important to Astronomers?
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Teaching
Ideas
- Challenge
students to increase the illuminance of a light source by using
light or reflective surfaces as opposed to dark surfaces. Have
students demonstrate their ideas.
-
Discuss with students the importance of the Inverse Square Law
to astronomers. Who else might use this formula?
- Use
the set-up for the demonstration to make silhouettes of students.
Is there a better place for the student to sit? How can you make
the shadow be an exact silhouette?
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Activity
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Class
Periods Needed to Complete
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Teaching
Approaches to Consider
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Features
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3.
How to Read a Light Bulb Package
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one
or two
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Small
group work in class
Independent
work at home
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Photo
Feature: Consumer-Friendly Packaging
Sidebar:
Design Your Own Bedroom
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Teaching
Ideas
- Have
small groups work together to make bar graphs of their findings.
How else could they diagram their research?
- Challenge
students to write their own advertisement for the most efficient
light bulb. The ad could be a poster, a radio spot, or a television
commercial. Remind students to use their findings to be persuasive.
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