s8pe-414ci-ca
10/31/05
7:14 PM
MAZER
Page 459
Content Standard
8.4.b Students know that the Sun is one of many stars in the Milky Way galaxy and
that stars may differ in size, temperature, and color.
Tape the negative terminal, or flat end, of one
battery to the positive terminal of another
battery. Tape a piece of copper wire to each end,
and connect the wires to
a light-bulb holder.
Because two batteries
will provide electricity
to the bulb in this
holder, the wire in
the bulb will be
hotter than the wire
in the bulb powered
by one battery.
step 4
With the room darkened, insert a bulb into each
light-bulb holder. If the bulb connected to two
batteries does not light up, you may need to press
the two batteries together with your fingers.
Place the photometer halfway between the two
light bulbs. Compare the brightnesses of the two
light sources. Record your observations in your
Science Notebook.
Move the photometer closer to the cooler bulb
until both sides of the photometer are equally
bright. Compare the colors of the two light
sources. Record your observations in your
Science Notebook. To avoid draining the
batteries, remove the bulbs from the holders
when you have completed this step.
Investigation Standard
8.9.a Plan and conduct a scientific investigation to test a hypothesis.
Observe and Analyze
Write
It Up
1. RECORD OBSERVATIONS Draw the
setup of your photometer and light sources.
Be sure your data table is complete with
descriptions of brightness and color.
2. IDENTIFY Identify the variables
in this experiment. List them in
your Science Notebook.
Write
Conclude
It Up
1. INTERPRET Answer the question in
the problem. Compare your results with
your hypothesis.
2. ANALYZE How does distance affect your
perception of the brightness of an object?
3. APPLY Judging by the results of the investigation, would you expect a red star or a
yellow star to be hotter? Explain why.
INVESTIGATE Further
CHALLENGE Connect an incandescent lamp
to a dimmer switch. Write a procedure to show
how you would use a photometer to show the
relationship between the color and the temperature of the bulb as it fades from brightest to
dimmest. Then carry out your procedure.
step 6
olor
ightness, and C
Temperature, Br
nalyze
Observe and A
s of Light from
Table 1. Propertie
Two Sources
Cooler Bulb
(one battery)
Warmer Bulb
(two batteries)
Brightness
Color
Chapter 14: Stars, Galaxies, and the Universe 459
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