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Earth and Space - The Solar System and Planets

Grade 3IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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The Solar System consists of the Sun and everything that orbits around it, including 88 major planets, their moons, dwarf planets, and asteroids.

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The Sun is a star at the center of the Solar System. It provides energy in the form of light and heat. Its surface temperature is approximately 5,500∘C5,500^{\circ}C.

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The four inner planets (Mercury, Venus, Earth, and Mars) are called terrestrial planets because they are made mostly of rock and metal.

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The four outer planets (Jupiter, Saturn, Uranus, and Neptune) are known as Gas Giants or Ice Giants. They are much larger than the terrestrial planets.

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Rotation is the spinning of a planet on its axis. For Earth, 11 rotation =24= 24 hours, which creates day and night.

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Revolution is the movement of a planet around the Sun. Earth's revolution takes approximately 365.25365.25 days, which we define as 11 year.

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The Moon is Earth's only natural satellite. It does not produce its own light but reflects light from the Sun.

📐Formulae

1 Earth Year≈365.25 days1 \text{ Earth Year} \approx 365.25 \text{ days}

1 Earth Day=24 hours1 \text{ Earth Day} = 24 \text{ hours}

Total Planets=8\text{Total Planets} = 8

Order from Sun: Mercury<Venus<Earth<Mars<Jupiter<Saturn<Uranus<Neptune\text{Order from Sun: Mercury} < \text{Venus} < \text{Earth} < \text{Mars} < \text{Jupiter} < \text{Saturn} < \text{Uranus} < \text{Neptune}

💡Examples

Problem 1:

If Earth takes 2424 hours to complete one full rotation, how many hours does it take to complete 33 rotations?

Solution:

3×24=723 \times 24 = 72 hours

Explanation:

Since one rotation equals one day (2424 hours), we multiply the number of days by the hours in a single day.

Problem 2:

Venus is the hottest planet with an average surface temperature of about 465∘C465^{\circ}C, while Earth's average is about 15∘C15^{\circ}C. What is the difference in temperature?

Solution:

465∘C−15∘C=450∘C465^{\circ}C - 15^{\circ}C = 450^{\circ}C

Explanation:

To find the difference, we subtract the lower temperature from the higher temperature using the Celsius scale.

Problem 3:

A leap year occurs every 44 years to account for the extra 0.250.25 days in Earth's revolution. Calculate the total extra time added over 44 years.

Solution:

0.25×4=10.25 \times 4 = 1 full day

Explanation:

Because Earth takes 365.25365.25 days to orbit the Sun, adding the 0.250.25 (or 14\frac{1}{4}) of a day over four years equals 11 full day (February 29th).