#5036 Daily Warm-Ups: Nonfiction Reading
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Warm-Up
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4
Name ______________________________________________
Check Your Understanding
1.
What is the main idea of the passage?
a. Pluto got smaller.
c. There are reasons Pluto is no longer considered a
planet.
b. Pluto is not a planet.
d. Pluto was discovered by an American.
2.
Which of the following statements is an opinion and
not a fact?
a. Pluto was found to be smaller than several moons.
b. Pluto was the only planet discovered by an American.
c. Pluto should be considered a planet.
d. A schoolgirl won the competition to name the planet.
3.
What inference can you make about the description of a dwarf planet?
a. Planets have to be bigger than most or all moons to be considered a conventional planet.
b. Planets should be much larger than their own moon to be considered a regular planet.
c. Planets should have conventional orbits, rather than eccentric ones, to be labeled a regular
planet.
d. all of the above
4.
How did Pluto get its name?
a. It was named for a child’s pet.
c. It was named for a god of the underworld.
b. It was named for a cartoon dog.
d. all of the above
Many Americans were upset when
astronomers removed Pluto from the list of
planets. It is no longer the ninth planet in the
solar system. They labeled it a dwarf planet
along with a larger object named Eris. Both
objects are located in a zone beyond Neptune
called the Kuiper Belt. Dwarf planets are
much smaller than the other eight planets.
Pluto was the only planet discovered by an
American. An astronomer from Kansas
named Clyde Tombaugh found it. He had
carefully compared photos of an area of space
beyond Neptune. This area was thought
to contain a ninth planet. He spent more
than 7,000 hours over more than two years
comparing photographs of light. He was
trying to discover the movement of a planet
against the background stars. On February 18,
1930, Tombaugh discovered this movement.
An eleven-year-old English schoolgirl won
a contest to name the planet. She suggested
Pluto, who is the god of the underworld in
ancient myths.
Why was Pluto removed from the list of
major planets? In a word—size. Charon, a
moon orbiting Pluto, was discovered. It was
about half the size of Pluto. Moons are not
that large compared to the planets they orbit.
Scientists were also able to determine Pluto’s
actual size, which was quite a bit smaller
than originally thought. Pluto was found to
be smaller than several moons, including our
own. Its orbit was also very different from the
other planets. Pluto is, of course, still there.
It just doesn’t have as big of a reputation
anymore.
Scientifically Speaking
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