K-6 Activities - Dudley Observatory

Objective
Stars and Light Pollution,
Activity 4-4
The student should be able to observe and discuss the concept that stars continually
shine but may not be seen with the naked eye due to a phenomenon known as light
pollution.
Procedure
• Turn down the side lamps on the projector. Adjust the projector to its lowest setting.
No star should be seen. Ask the students to describe what they see.
• Slowly increase the brightness of the projector (with the Starfield Cylinder in
place). Ask students to tell you when they see the first star. Continue to turn knob
until the entire starfield is lighted. Discuss the concept that stars are of different
brightness (called magnitude).
• Turn the dimmer knob on projector down from full brightness about 1/2 turn.
Slowly turn on the variable light source. Discuss the comparison of this light to
the rising sun with the children.
• As the Variable Light Source reaches full strength, ask the students the difference
they see in the starfield in the planetarium sky. Emphasize the concept that stars
make their own light and are constantly emitting light, but our eyes will only register
that light if there is no other stronger light source interfering. In this case, the
Variable Light Source (sun simulator) is stronger than many of the stars of lower
magnitude, thereby rendering them invisible to our eye.
• Discuss real life situations where this same thing happens.
Extension Activity
Have students observe the sky from various locations such as: urban, rural, and
isolated places away from lights.
Materials
• STARLAB Portable Planetarium
• Projector
• Starfield Cylinder
• Variable Light Source (see Appendix
in 7-9 section)
• B–59 • K–6 Activities