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MP 1 Science Quarterly Review (Honors)
Earth’s orbit and seasons
1. What is the difference between rotation and revolution? What is period of revolution?
Earth rotates by spinning on its axis. One rotation takes 24 hours. Earth revolves
(or orbits) around the Sun. One revolution takes about 365 days.
A period of revolution is the time it takes a moon or planet to make one complete
orbit.
2. What causes the apparent movement of the sun across the sky during the day on Earth?
The rotation of Earth to the East causes the sun to move across the sky as your
viewpoint turns toward the sun until noon then away until sundown.
3. What is the shape of a planet's orbit?
Planets orbit in elliptical (oval) orbits. The orbits become more circular over time
but never become a perfect circle.
4. Where are the direct rays of the sun on summer solstice? On winter solstice?
In the Northern Hemisphere on the summer solstice the direct rays are over the
Tropic of Cancer. On the winter solstice it is over the Tropic of Capricorn.
5. What are the dates of the solstices and equinoxes in the Northern Hemisphere?
Vernal equinox- March 21; Summer solstice- June 21; Autumnal equinoxSeptember 23; Winter solstice- December 21/22
6. What is the angle of Earth’s tilt? How does it affect the number of hours of daylight?
About 23.5 degrees. When the pole is tilted toward the sun the hours of daylight
increase 24 hours of daylight above the Arctic/Antarctic Circle. When the pole is
tilted away from the sun the hours daylight decrease to 24 hours of darkness above
the Arctic/Antarctic Circle.
7. What would happen if Earth tipped over so that its axis was tilted more? Tilted less?
The greater the tilt, the more extreme the variations in light and temperature
between winter and summer. With less of a tilt there would be less of a seasonal
change, equatorial temperatures would increase, and decreases in light and
temperature would be determined by latitude only.
Newton’s Laws and Gravity
8. What are Newton’s 3 Laws of Motion?
1- An object at rest remains at rest and an object in motion will remain in motion (in
a straight line and at a constant speed) unless acted upon by an unbalanced force.
2- F=ma (Force=mass x acceleration)
3- For every action there is an equal and opposite reaction.
9. What two forces keep Earth is kept in orbit around the sun?
Inertia keeps Earth moving forward and gravity pulls the Sun and Earth toward each
other. The combination results in Earth following an elliptical orbit.
10.What are some unbalanced forces that can affect inertia?
Friction, drag, gravity, collision with another object, etc.
11.What 2 factors affect gravity? How do they affect it? (Law of Universal Gravitation)
The mass of the objects and the distance (squared) between them (measured from
the centers of the objects). As mass increases, gravity increases. As distance
increases, gravity decreases (by a factor of 4).
12.Which of Newton’s Laws best describes a sled sliding on a flat, icy surface with a
constant velocity?
Inertia, the first law. An object in motion will remain in motion, in a straight line,
and at a constant velocity.
13.What is inertia? How does it affect you when riding in a car? Why must trucks be
concerned with it?
*Inertia is an object’s resistance to change. If it’s moving it will continue to move,
if at rest it will continue at remain at rest. *Inertia will cause you to lean to the left
when you are riding in a car that turns to the right. *Because trucks are heavy and
have a high center of gravity they will respond more radically to Newton’s Laws
when speeding around a curve or down a hill.
14.According to Newton’s first law of motion, what will happen to a moving object that is
not acted on by an unbalanced force?
It will continue to move in the same direction, in a straight line, and at a constant
speed.
Stars and the Universe
15.Approximately, how old is the Universe?
The Universe is approximately 13.8 billion years old.
16.Why are supernova constructive events?
All elements higher on the periodic table than hydrogen or helium are created
through fusion in the cores of stars. But it takes a supernova to create the elements
heavier than iron and then scatter them throughout the Universe.
17.What is the end stage of stars based upon their size? (ex. What will a star 20x more
massive than our sun become)
Small and medium sized stars end their life as a white dwarf (and eventually a black
dwarf). More massive stars (up to about 20x) become neutron stars. Only the most
massive stars become black holes.
18.Define a light-year.
The distance light travels in a year, about 6 trillion miles, or 9.5 trillion kilometers.
19.What are the colors of the stars from hottest to coolest? What about the spectra?
Blue, White, Yellow, Orange, Red. Spectral types are O-B-A-F-G-K-M each of
which is subdivided into numbers from 0-9 (O0 stars are the hottest, M9 the
coolest). Mnemonic for spectra “Oh Be A Fine Girl (or Guy), Kiss Me.
20.What methods are used to find planets?
Wobble method (motion of the star), Doppler Effect (change in starlight
wavelength), Transit method (starlight intensity).
21.Understand what the Hertzsprung-Russell diagram shows, and be able to identify types of
stars on it.
The coolest stars are on the right side of the diagram and get hotter as you move
to the left. Smaller stars are on the bottom of the diagram and grow larger (and
more luminous) as you move up.
The Process of Science
22.Hypothesis has to be in an IF—THEN—BECAUSE format.
23.Independent variables are the IF (the cause). Dependent variables are the THEN (the
effect).
24.Controlled variables are those things that must be the SAME in both your experimental
and control group.
25.Observations are made using the 5 senses to describe something. Inferences are
conclusions you make based on observations.