BACKGROUND:
The Universe is everything in outer space, including
stars, black holes, quasars, and galaxies. The Solar System is part of the
Universe. It is composed of the Sun, the nine planets, and many small
objects like comets and asteroids. The Sun radiates light while planets and
asteroids are visible only by reflected sunlight.
The planets are all rotating around their own axis, as
they revolve around the Sun. The planets are divided into inner and outer
planets. The inner planets are all composed of "rock," just like
the Earth. The outer planets, except for Pluto, are composed of gas.
We are learning new information every year.
Mercury is the closest planet to the Sun. It
orbits the Sun quickly, once every 88 days. It rotates slowly, however, only
once every 59 days. Mercury is small, about 4850 kilometers (~3000 miles) in
diameter. Because Mercury is so close to the Sun, the side of its surface
that faces the Sun is very hot, ~700oK. The surface of Mercury is
gray to orange in color, and is covered with craters. Mercury is named for a
mythical god who ran very fast.
Venus, the second planet away from the Sun, is
Earth’s closest neighbor. It is about the same size as the Earth, a little
over 12,000 kilometers (7300 miles) in diameter. Venus has a very thick
atmosphere, composed largely of sulphuric acid and CO2. We could
not breathe on Venus, because the atmosphere would be very toxic to humans.
This atmosphere gives Venus a brownish-yellow color. It also traps heat (the
greenhouse effect) making the surface of Venus the hottest in the Solar
System, about 750oK. Venus rotates very slowly, taking 243 days
to complete one turn. It is named for the Roman goddess of love.
Earth is a little more than 12,000 kilometers
in diameter. It differs from the other planets because it has liquid water
on its surface, maintains life, and has active plate movement. It rotates on
its axis every 24 hours (a day) and revolves around the Sun every 365 days
(a year). The Earth has one moon.
Mars is a little more than half the size of the
Earth, having a diameter of 6,790 kilometers. It takes Mars 687 days to
revolve once around the Sun. It rotates at about the same speed as the
Earth, taking 24.6 hours. Mars has a very thin atmosphere which is composed
largely of CO2. Its surface is very cold, and is covered with
craters, volcanoes, and large canyons. Mars is reddish in color. Mars has two
small moons. It is named for the Roman god of war.
Jupiter is the largest planet in the Solar
System, with a diameter of 142,980 kilometers, more than 11 times wider than
the Earth. Jupiter orbits the Sun once every 12 years. It rotates very fast,
in only 10 hours. Its surface is made up of gas (mostly hydrogen), so that
if you landed on the surface you would sink into it. Jupiter probably has a
core of metallic hydrogen and rock, although evidence for this is
theoretical. The outer gaseous part of Jupiter is broken into bands of
white, yellow, red, and brown clouds. Huge oval-shaped storms also occur on
the surface. Jupiter has at least 16 moons. Jupiter is named for the Roman
supreme god of heaven.
Saturn is well known for its system of three
rings. It is a large planet: at 120,536 kilometers it is only a little
smaller than Jupiter. It revolves around the Sun in 12 years, and rotates a
little more than 10 hours. Like Jupiter, Saturn is composed mostly of gas, and has a core composed of rock and metallic hydrogen. The surface of
Saturn looks banded, and has a brown-yellow, butterscotch color. Saturn’s
rings are probably composed of small particles of ice and rock. Saturn has
at least 20 moons. It is named for the Roman god of agriculture.
Uranus is 51,118 kilometers in diameter, about
4.4 times the size of the Earth. It revolves around the Sun slowly, taking
84 years to complete one orbit. It rotates in about 17 hours. It is covered
by a thick layer of gas, and has a fairly uniform blue-green color. Uranus
has both at least 15 satellites, and is surrounded by a system of nine
rings. It is named for another Roman god, the grandfather of Jupiter
Neptune is slightly smaller than Uranus, with a
diameter of 49,500 kilometers. It circles the Sun once every 165 years, and
rotates in 16 hours. Its atmosphere appears blue , and is marked by large
dark blue storm systems. It is surrounded by a system of five rings and at
least 8 moons. Neptune is named for the Roman god of the ocean.
Pluto is the most distant "official" planet from the Sun.
It has an eccentric, oval-shaped orbit, which is tilted with respect to the
rest of the Solar System. Pluto revolves around the Sun in 248 years, and
rotates in a period of 6.4 days. Pluto is probably composed of rock. Its
surface and color are unknown. It has one large moon called Charon.. Pluto is named for the
Roman god of outer darkness.
In 2004, "Sedna" was discovered which
is now the most distinct body that orbits the Sun. It is 3 times as
far as Pluto. Sedna is slightly smaller than Pluto. It is not
officially a planet at this time.
PROCEDURE:
- Discuss the nine planets of the Solar System by reading How many
Planets? with the students. Go
over a few of the "facts," gearing the discussion toward the
worksheet or pictures of the planets. Use the Solar System placemats to
help students locate the different planets and to understand their
orbits.
Mercury: is the closest to the Sun, it is not very big
Venus: has a very spooky atmosphere, that makes this planet the
hottest in the Solar System
Earth: is one of the planets, noted for its forest, water, and life
Mars: is about the same size as Earth
Jupiter: is the largest planet, and it not made up of just rocks, it
is made in part of gas
Saturn: is noted for its rings, and it like Jupiter is more of a gas
planet
Uranus: has some rings, and is a gas planet also
Neptune: has some rings, and it a gas planet
Pluto: terrestrial planet, has only one moon, farthest planet away
from Sun
- Students can color the planets on the worksheet. Note that the
planets are not to scale. Have the students cut out their pictures, and
place them on top of the correct planet on the Solar System Placemat.
- Students can use clay or play dough to make models of the
planets. Have the students try to make models that reflect the real
sizes of the planets, as shown on the the Solar System Placemat. You may
have them mount their models on toothpicks embedded in clay at its base.
HOW TO MAKE PLAY DOUGH
MATERIALS:
250 ml flour
125 ml salt
5 ml cream of tartar
250 ml water
about 1/2 ml food coloring
about 1/2 ml oil
Cook this mixture, over medium heat, stirring it constantly until it
forms a dough-like texture. Knead it briefly, after the mixture has
cooled. Multiply this recipe by 6 to get enough for a class of 30
students, but it should be made in two batches. Large amounts of dough
are difficult to stir because the mixture becomes firm. Store the play
dough in a plastic bag or a margarine container.
