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Objective – After reading a science article, I can answer questions about the article.
Are all planets round?
By Ask Smithsonian Smithsonian.com December 03, 2015
You asked us, "Why are all planets round?"
In a nutshell? Gravity.
We all know what gravity is, right?
It's what makes apples tumble from trees and people fall flat on their faces. The bigger
an object is, the stronger its gravitational field.
And planets are pretty big, so gravity acts on them as a strong force. It pulls everything
together towards their center.
And the resulting shape is a sphere.
Now, planets aren't actually perfectly round - they've got a bit of what you might call a
spare tire.
Planets spin around their axes and the force generated by the spinning works against
gravity and causes a planet to bulge out at its equator.
Join the club, planets.
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Objective – After reading a science article, I can answer questions about the article.
What keeps satellites from falling out of the sky?
By Ask Smithsonian Smithsonian.com November 18, 2015
You asked us, "What keeps satellites from falling out of the sky?"
Over the last half-century, more than 2,500 satellites have followed the first one into
space. What keeps them all afloat? It is a delicate balance between a satellite's speed
and the pull of gravity.
Satellites are basically constantly falling. Crazy, right?
They fall at the same rate that the curve of the Earth falls away from them if they're
moving at the right speed. Which means instead of racing farther out into space or
spiraling down to Earth, they hang out in orbit around the planet.
Corrections are often needed to keep a satellite on the straight and narrow.
Earth's gravity is stronger in some places than others. Satellites can get pulled around
by the sun, the moon and even the planet Jupiter.
You would think gravity was enough to deal with. But, satellites in low earth orbit such
as the Hubble Space Telescope can also get pulled out of their orbit by drag from the
atmosphere.
Not to mention the ongoing game of Frogger that satellites have to play. That's so
they can avoid space junk and other high flyers.
Heads up!
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Objective – After reading a science article, I can answer questions about the article.
Chaos Among the Planets
Kate Ramsayer
From Science News for Kids June 1, 2005.
Once upon a time, billions of years ago, the gas giants had different orbits around the
Sun than they follow now.
Jupiter, Saturn, Uranus, and Neptune were once grouped together, closer to the Sun.
Under the influence of gravity, the planets broke out of their original orbits and began
to reorganize the outer Solar System.
A new theory suggests that the four giant planets, shown here in their current orbits
around the Sun, were once much closer together.
As the scientists tell it, it starts a few million years after the Solar System's birth. At
first, the four giant planets had tight orbits. Neptune, for example, was only half as far
away from the Sun as it now. A slowly circulating band of ice, dust, and gas lay beyond
these planets.
Ice, dust, and gas might not seem like a match for huge planets. But, the pull of gravity
between the particles and the planets caused the planets to slowly break out of their
orbits. Jupiter moved a closer to the Sun, and the other three planets moved further
away.
All was peaceful in until the orbits of Saturn and Jupiter aligned. Saturn took exactly
twice as long as its neighbor to go around the Sun. The increased gravitational tug of
the two planets acting together caused an avalanche of effects.
Saturn's orbit changed shape slightly, which threw off the orbits of Uranus and
Neptune. The orbits of these two planets started looking like squished ovals. At times,
the two planets even crossed paths.
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Objective – After reading a science article, I can answer questions about the article.
And that's when things got really crazy. Uranus and Neptune started racing through
the band of ice, dust, and gas. This scattered rubble throughout the Solar System. The
gas giants ended up in their current orbits.
Some of the scattered material became trapped around Jupiter. This could explain the
presence of objects known as the Trojan asteroids.
Some of the rubble could have been flung closer to Earth. Object his the Moon and
the inner planets. It may have created the huge craters on the Moon and elsewhere.
No one knows for sure whether all this really happened. But, by using computers to
play complex games of “what if,” scientists can get a better idea of what might have
happened to create the Solar System as we know it.
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Objective – After reading a science article, I can answer questions about the article.
Name ___________________________________________________________
Gravity Articles Worksheet
Are all planets round?
1. This is why all planet are round.
a. Electromagnetism
b. Gravity
c. Strong force
d. Weak force
2. This makes apples fall from a tree.
a. Electromagnetism
b. Gravity
c. Strong force
d. Weak force
3. The ______________ an object, the ______________ its gravitational field.
a. bigger, stronger
b. smaller, weaker
4. Gravity pulls everything towards …
a. its center.
b. its exterior.
c. the Sun.
d. its surface.
5. The resulting shape of a planet is a(n)…
a. ellipse.
b. sphere.
c. square.
d. triangle.
What keeps satellites from falling out of the sky?
6. Over the last half-century over _______________ satellites have been launched into
Earth orbit. (Enter a number, no comma!)
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Objective – After reading a science article, I can answer questions about the article.
7. Satellites keep “afloat” through a balance of its…
a. gravity
b. speed.
c. gravity and speed.
8. Satellites are basically constantly falling.
a. True
b. False
9. Satellites in low Earth orbit face drag from…
a. solar wind.
b. the atmosphere.
c. the Moon’s gravity.
d. the Sun’s gravity.
Chaos Among the Planets
10. According to the article, these four planets were bunched together and nearer to
the Sun. (There are more than two answers to this question.)
a. Earth
b. Jupiter
c. Mars
d. Mercury
e. Neptune
f. Saturn
g. Uranus
h. Venus
11. This force caused the violent rearrangement of our Solar System.
a. Electromagnetic
b. Gravity
c. Strong
d. Weak
12. Ice, dust, and gas were not much of a match for huge planets.
a. True
b. False
13. This planet’s orbit changed slightly and threw off the orbits of Uranus and
Neptune.
a. Saturn
b. Earth
c. Jupiter
d. Mercury
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Objective – After reading a science article, I can answer questions about the article.
14. Some of the scattered materials formed this group of asteroids.
a. Apollo
b. Centaur
c. Roman
d. Trojan
15. Some of the debris was thrown towards Earth. It may have been responsible for
craters on the Moon and planets in the inner Solar System.
a. True
b. False
16. Scientists are positive this happened.
a. True
b. False
Scoring Guide
95-100% - 4
90-94% - 3.5
85-89% - 3
75-84% - 2.5
65-74% - 2
55-64% - 1.5
45-54% - 1
1-44% - .5
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Objective – After reading a science article, I can answer questions about the article.
Gravity Articles Worksheet – Key I
Are all planets round?
1. This is why all planet are round.
a. Electromagnetism
b. Gravity
c. Strong force
d. Weak force
b. Gravity
1. b
2. This makes apples fall from a tree.
a. Electromagnetism
b. Gravity
c. Strong force
d. Weak force
b. Gravity
2. b
3. The ______________ an object, the ______________ its gravitational field.
a. bigger, stronger
b. smaller, weaker
a. bigger, stronger
3. a (2 choices)
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Objective – After reading a science article, I can answer questions about the article.
4. Gravity pulls everything towards …
a. its center.
b. its exterior.
c. the Sun.
d. its surface.
a. its center.
4. a
5. The resulting shape of a planet is a(n)…
a. ellipse.
b. sphere.
c. square.
d. triangle.
b. sphere.
5. b
What keeps satellites from falling out of the sky?
6. Over the last half-century over _______________ satellites have been launched into
Earth orbit. (Enter a number, no comma!)
2500
6. 2500
7. Satellites keep “afloat” through a balance of its…
a. gravity
b. speed.
c. gravity and speed.
c. gravity and speed.
7. c
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Objective – After reading a science article, I can answer questions about the article.
8. Satellites are basically constantly falling.
a. True
b. False
a. True
8. a (2 choices)
9. Satellites in low Earth orbit face drag from…
a. solar wind.
b. the atmosphere.
c. the Moon’s gravity.
d. the Sun’s gravity.
b. the atmosphere
9. b
Chaos Among the Planets
10. According to the article, these four planets were bunched together and nearer to
the Sun. (There are more than two answers to this question.)
b. Jupiter, e. Neptune, f. Saturn, g. Uranus
11. This force caused the violent rearrangement of our Solar System.
b. Gravity
12. Ice, dust, and gas were not much of a match for huge planets.
a. True
13. This planet’s orbit changed slightly and threw off the orbits of Uranus and
Neptune.
a. Saturn
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Objective – After reading a science article, I can answer questions about the article.
14. Some of the scattered materials formed this group of asteroids.
d. Trojan
15. Some of the debris was thrown towards Earth. It may have been responsible for
craters on the Moon and planets in the inner Solar System.
a. True
16. Scientists are positive this happened.
b. False
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Objective – After reading a science article, I can answer questions about the article.
Gravity Articles Worksheet – Key II
1. b
2. b
3. a (2 choices)
4. a
5. b
6. 2500
7. c
8. a (2 choices)
9. b
10. b, e, f, g (8 choices)
11 b
12. a (2 choices)
13. a
14. d
15. a (2 choices)
16. b (2 choices)
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Objective – After reading a science article, I can answer questions about the article.
Gravity Articles Worksheet
Coring Guide
15-16 – 4
14 – 3.5
13 – 3
12 – 2.5
10-11 – 2
9 – 1.5
7-8 – 1
1-6 – .5
0–0
95-100% - 4
90-94% - 3.5
85-89% - 3
75-84% - 2.5
65-74% - 2
55-64% - 1.5
45-54% - 1
1-44% - .5
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