1.3 Notes

Name: ___________________________________ Date: _________________ Period: ________
1.3 Notes
1) Theory
a) A hypothesis or a set of hypotheses that is supported by the results of experimentation
and observation.
b) Provides a general explanation for scientific observations.
2) Scientific Law
a) A rule that correctly describes a natural phenomenon.
b) A theory must be proven true every time it is tested to become a law.
3) Spectrum
a) Isaac Newton discovered that sunlight passing through a glass prism produces a band of
b) These colors are red, orange, yellow, green, blue, and violet.
4) Wavelength
a) The distance from the crest of one wave to the crest of the next wave.
b) Each color in the spectrum has a unique wavelength.
c) The wavelengths decrease in length from red to violet.
5) Bright-Light Spectrum
a) Each element on the periodic table of elements, when heated, will produce its own
spectrum of colors.
b) Since these elements only produce a series of thin colored lines spaced at uneven
intervals we know they produce specific wavelengths and the spectrum is unique to the
6) Doppler Effect
a) The apparent shift in the wavelengths of energy emitted by an energy source moving
away from or toward an observer.
b) When light, or energy, is moving toward a person the wavelengths of the light appear to
become shorter, or moving toward the blue end of the spectrum.
c) When light, or energy, is moving away from a person the wavelengths of the light appear
to become longer, or moving toward the red end of the spectrum.
d) The faster the energy source is moving the faster the wavelength the shift appears to be.
7) Red Shift
a) Spectroscope
i) A device that contains a prism which splits light into a spectrum of different colors
and wavelengths.
ii) Scientists used a spectroscope to view the spectrum of various stars, and by
comparing the spectrum to known elements they are able to determine what elements
are in each star.
b) Observing the spectrum of stars, scientists noticed that most galaxies are shifted toward
the red end of the spectrum. Which indicates they are moving away from Earth.
i) These observations indicate that the universe is expanding.
Name: ___________________________________ Date: _________________ Period: ________
8) Big Bang Theory
a) Scientists believe that billions of years ago all of the matter and energy was compressed
into an extremely small volume.
b) Approximately 15 billion years ago, scientists believe, all the matter and energy began
expanding outward in a giant cloud form.
c) This giant cloud eventually began forming clumps of matter and energy which we now
know as galaxies.
d) This outward movement of matter is still occurring today. Which is why we see the red
shift in galaxies.
e) This theory was greatly doubted by the scientific world until researches detected low
levels of energy evenly distributed throughout the universe called background radiation.
f) This theory is still a theory, cannot be proven to law, and must continue to be tested until
proved or disproved.