BigBangSE.
Name: Date:
Student Exploration: Big Bang Theory – Hubble’s Law
Vocabulary: absolute brightness, absorption spectrum, apparent brightness, Big
Bang theory, blueshift, Cepheid variable, Doppler shift, Hubble constant, Hubble’s
law, luminosity, megaparsec, period, redshift, spectrograph
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Standing by the side of a lonely highway at night, you see two motorcycle
headlights, one in each direction. The headlight on your left appears brighter than
the one on your right.
1. If the headlights are equally bright, which motorcycle is closer?
Explain:
2. Suppose the dim-looking headlight on the right is actually a small light on
the front of a bicycle. What can you conclude about the distance of the
motorcycle and bicycle?
Gizmo Warm-up
In 1912, an astronomer named Henrietta Swan
Leavitt studied a class of stars called Cepheid
variables. These stars change from bright to dim
to bright again. Her discoveries led to a method
of measuring distances to other galaxies and
eventually helped to support the Big Bang theory
of the origin of the universe.
In the Big Bang Theory – Hubble’s Law Gizmo, select Region A. Look at the image of
the Andromeda Galaxy, a galaxy relatively close to our own Milky Way galaxy.
1. Locate the two Cepheid variables, the stars that change in brightness over
time. Star A-091 is the yellow star, and A-171 is the white star.
A. Which star reaches a greater apparent brightness?
B. Which star takes longer to pulse?
201
8
,BigBangSE.
2. Because both stars are in the same galaxy, they are about the same distance
from Earth. Based on what you see, how is the brightness of the star related
to how quickly it pulses?
201
8
, BigBangSE.
201
8
Name: Date:
Student Exploration: Big Bang Theory – Hubble’s Law
Vocabulary: absolute brightness, absorption spectrum, apparent brightness, Big
Bang theory, blueshift, Cepheid variable, Doppler shift, Hubble constant, Hubble’s
law, luminosity, megaparsec, period, redshift, spectrograph
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Standing by the side of a lonely highway at night, you see two motorcycle
headlights, one in each direction. The headlight on your left appears brighter than
the one on your right.
1. If the headlights are equally bright, which motorcycle is closer?
Explain:
2. Suppose the dim-looking headlight on the right is actually a small light on
the front of a bicycle. What can you conclude about the distance of the
motorcycle and bicycle?
Gizmo Warm-up
In 1912, an astronomer named Henrietta Swan
Leavitt studied a class of stars called Cepheid
variables. These stars change from bright to dim
to bright again. Her discoveries led to a method
of measuring distances to other galaxies and
eventually helped to support the Big Bang theory
of the origin of the universe.
In the Big Bang Theory – Hubble’s Law Gizmo, select Region A. Look at the image of
the Andromeda Galaxy, a galaxy relatively close to our own Milky Way galaxy.
1. Locate the two Cepheid variables, the stars that change in brightness over
time. Star A-091 is the yellow star, and A-171 is the white star.
A. Which star reaches a greater apparent brightness?
B. Which star takes longer to pulse?
201
8
,BigBangSE.
2. Because both stars are in the same galaxy, they are about the same distance
from Earth. Based on what you see, how is the brightness of the star related
to how quickly it pulses?
201
8
, BigBangSE.
201
8
