Physical Science Module 16
Terms in this set (31)
The process by which two or more small nuclei fuse to make a bigger nucleus.
The process by which a large nucleus is split into smaller nuclei.
The amount of isotope necessary to sustain a chain reaction.
The brightness of a star, corrected for distance, on a scale of -8 to +19. The smaller the number the brighter the star.
The brightness of a star as seen in the night sky. The smaller the number, the brighter the star.
The distance light could travel along a straight line in one year.
A large ensemble of stars, all interacting through the gravitational force and orbiting around a common center.
From the inside to the outside, name the four regions of the sun.
Core, radiative zone, convection zone, photosphere.
How does the sun get its power? In which region of the sun does this process occur?
Nuclear Fusion. The core.
What part of the sun do we see?
A 251Cf nucleus is bombarded with a neutron. It breaks down into a 124Sn nucleus, a 120Cd nucleus and seven neutrons. Is this nuclear fission or nuclear fusion?
Two 4He nuclei collide and turn into a 7Be nucleus and one neutron. Is this nuclear fusion or nuclear fission?
For both the nuclear fusion that occurs in the sun and the nuclear fission that occurs in a nuclear power power plant, what can we say about the mass of the starting materials compared to the mass of what's made in the end?
It is larger.
Why is it impossible for a nuclear power plant to have a nuclear explosion?
A power plant does not have significantly more than the critical mass of the large nucleus that is breaking apart.
Why is nuclear fusion considered a better option for energy production than nuclear fission?
Its byproducts are not radioactive, there is no chance of a meltdown, and the starting materials are cheap.
If nuclear fusion is a better option, why don't we use it?
We have not mastered the technology yet.
Using the H-R Diagram below, classify the following stars.
a. Magnitude -1, Spectral Letter K
b. Magnitude 0, Spectral Letter B
c. Magnitude -7, Spectral Letter F
d. Magnitude 11, Spectral Letter B
A. Red giants. B. Main Sequence. C. Supergiants. D. White Dwarfs.
Which of the stars in#11 is most like our sun?
Order the four terms in #11 in terms of increasing size.
D. B. A. C.
Order the four stars in #11 in terms of increasing brightness.
D. B. A. C.
Which of the stars is the coolest?
What similarity exists between novas, supernovas, and pulsating variables?
They have a pulsing brightness.
What is the big difference between novas, supernovas, and pulsating variables?
They're life span.
What most likely formed the crab nebula?
What are the two methods for measuring the distance from earth to a star? Which of the is the most accurate? Which can be used to measure long distances?
Parallax method, and the apparent magnitude method. Parallax. Apparent magnitude.
Why are Cepheid variables so important for measuring long distances in the universe?
As long as there is a Cepheid star nearby scientists can measure the exact distance from the earth, to the point your measuring.
What are the four basic types of galaxies? To which type does the Milky Way belong?
Spiral galaxies, elliptical galaxies, lenticular galaxies, irregular galaxies. Spiral galaxy.
Fill in the blanks: Stars group together to form ..., which group together to from ..., which group together to from ..., some of which group together to form ... .
Galaxies, groups, clusters, superclusters.
For the first three answers you gave in #22, give the names that apply to those in which earth's solar system belongs.
Milky Way, Local Group, Virgo Cluster.
Why do most astronomers believe the universe is expanding?
Because the light from nearly every galaxy experiences a red shift before it reaches the earth, and the red shift increases the farther the galaxy is from the earth.
If the universe is expanding, does the geometry of the expansion matter? If so, why?
Yes. Because, the theories that can be developed for the formation of the universe depend on that initial assumption.