seegongsik
Grade 5 (age 10-11)

grade 5 Solar System and Stars

The solar system is made up of the Sun, a star that shines by itself, the eight planets that travel around it, and moons, asteroids and comets. In order from the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune each follow their own orbit, and the farther out a planet is, the longer it takes to go around once. The planets differ a lot in size too: Jupiter, the largest, is about 11 times as wide as Earth, while Mercury, the smallest, is less than half as wide. In the first picture, watch the planets circle at different speeds; in the second, pick the planets one by one and compare their size with Earth's.

Meeting the solar system

50
☀ What is the solar system?
①The Sun is the star at the center of the solar system, giving off its own light and heat.
②Eight planets travel around the Sun. This is called revolution.
③In order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
④The farther out a planet is, the longer one trip takes; Neptune needs about 165 years.
⑤Since 2006, Pluto has been classed as a dwarf planet rather than a planet.

Comparing planet sizes

Earth
🪐 Kinds and sizes of planets
①Mercury, Venus, Earth and Mars are small planets made of hard rock.
②Jupiter and Saturn are huge planets made mostly of gas.
③Uranus and Neptune are planets with a lot of ice and gas.
④Jupiter is the largest planet, about 11 times as wide as Earth, and Mercury is the smallest.

What is a star?

Star vs. Planet
Star: shines by itself (Sun) / Planet: reflects starlight (Earth)
The stars twinkling in the night sky are suns very far away.
⭐ What is a star?
①A star is a body that gives off its own light and heat. The Sun is a star.
②The stars in the night sky shine like the Sun but are so far away that they look like tiny dots.
③A constellation is a picture made by joining bright stars and giving it a name, such as the Big Dipper, Cassiopeia and Orion.
④Polaris, the North Star, seems to stay almost still, so it helps us find north.

Summary

The solar system in one line
Me-V-E-Ma-J-S-U-N
This is the order from the Sun. A sentence like My Very Easy Method Just Speeds Up Naming helps you remember it.
🎯 Key points
①The solar system is the Sun, eight planets, moons, asteroids and comets.
②In order from the Sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
③Mercury, Venus, Earth and Mars are small rocky planets; from Jupiter outward, the planets are large.
④Stars shine by themselves; planets are seen because they reflect starlight.
⑤Constellations and Polaris help us find directions in the night sky.

Examples and Unit Test

Example 1
Name the first four planets in order from the Sun.
1
The order from the Sun is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
2
The first four of these are Mercury, Venus, Earth and Mars.
▸ Mercury, Venus, Earth, Mars
These four are all small, hard, rocky planets.
Example 2
What is the biggest difference between a star like the Sun and a planet like Earth?
1
A star gives off its own light and heat.
2
A planet cannot make its own light; we see it because it reflects starlight.
▸ A star shines by itself; a planet reflects starlight.
Even Venus, which looks so bright in the night sky, does not shine by itself; it is a planet reflecting sunlight.
Unit-test style
Which statement about the solar system and stars is correct?
①All planets give off their own light.
②The planet closest to the Sun is Mercury.
③The Sun is a planet.
④Jupiter is the smallest planet in the solar system.
⑤Stars are always closer to Earth than planets are.
▸ ② The planet closest to the Sun is Mercury.
1
Mercury comes first in order from the Sun, so it is the closest planet.
2
Planets do not make their own light but reflect it (①), the Sun is a star (③), Jupiter is the largest planet (④), and stars are much farther away than planets (⑤).
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Earth and Moon Motion
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Ecosystem

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