3rd Grade Space & Solar System Practice: Questions, Answers and Tips

Looking for 3rd grade space & solar system practice? Below are worked examples, the mistakes students make most, and practice questions with an answer key.

Every example below comes from BAMS Academy's Space & Solar System practice, the same questions students answer on the site.

Space & Solar System in 3rd grade, skill by skill

The planets, sun, and moon in our solar system. BAMS Academy breaks the unit into the skills below (part of all 3rd grade science topics). Each comes with one of its practice questions.

Name the phases of the moon and explain what causes them

A student observes that a thin, shrinking sliver of light appears just before the next new moon. Which moon phase is this? (Choices: Full moon; Waning crescent; New moon; First quarter.)

Answer: Waning crescent. When a thin, shrinking sliver of light appears just before the next new moon, the moon is at waning crescent. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.

Tonight a thin, growing sliver of light appears just after the new moon. What phase is the moon in? (Choices: New moon; Full moon; First quarter; Waxing crescent.)

Answer: Waxing crescent. When a thin, growing sliver of light appears just after the new moon, the moon is at waxing crescent. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.

Identify the planets of the solar system by their distinguishing features

Name the planet that is the planet famous for its bright rings. (Choices: Saturn; Earth; Mars; Mercury.)

Answer: Saturn. Saturn is the planet famous for its bright rings.

Name the planet that is the hottest planet, wrapped in thick clouds that trap heat. (Choices: Mercury; Earth; Venus; Mars.)

Answer: Venus. Venus is the hottest planet, wrapped in thick clouds that trap heat.

Name the planet that is the planet we live on, the only one known to have life. (Choices: Mercury; Jupiter; Earth; Mars.)

Answer: Earth. Earth is the planet we live on, the only one known to have life.

Worked examples

Example 1

Question: A student observes that more than half the moon is lit and the lit part is still growing. Which moon phase is this?

1. Full moon
2. New moon
3. First quarter
4. Waxing gibbous

How to solve it: When more than half the moon is lit and the lit part is still growing, the moon is at waxing gibbous. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.

Answer: Waxing gibbous

Why the other choices don't work:

• A student who picks "Full moon" usually confused the fully lit phase with the dark phase.
• A student who picks "New moon" usually confused the dark phase with the fully lit phase.
• A student who picks "First quarter" usually got the half-lit phases backwards — first quarter is growing, last quarter is shrinking.

Example 2

Question: Which moon phase is it when exactly half of the moon’s disk looks lit and the lit part is shrinking?

1. First quarter
2. Full moon
3. Last quarter
4. New moon

How to solve it: When exactly half of the moon’s disk looks lit and the lit part is shrinking, the moon is at last quarter. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.

Answer: Last quarter

Why the other choices don't work:

• A student who picks "First quarter" usually got the half-lit phases backwards — first quarter is growing, last quarter is shrinking.
• A student who picks "Full moon" usually confused the fully lit phase with the dark phase.
• A student who picks "New moon" usually confused the dark phase with the fully lit phase.

Common mistakes to watch for

• Question: Which moon phase is it when the whole lit side of the moon faces Earth? (Choices: Full moon; New moon; First quarter; Last quarter.)

  Answer: Full moon.

  A student who picks "Last quarter" usually got the half-lit phases backwards — last quarter is shrinking, first quarter is growing.

• Question: Name the planet that is the planet famous for its bright rings. (Choices: Saturn; Earth; Mars; Mercury.)

  Answer: Saturn.

  A student who picks "Mercury" usually assumed the closest planet to the sun must also be the hottest — Venus is, because of its thick atmosphere.

• Question: Name the planet that is the hottest planet, wrapped in thick clouds that trap heat. (Choices: Mercury; Earth; Venus; Mars.)

  Answer: Venus.

  A student who picks "Earth" usually confused Earth with another rocky inner planet.

• Question: Name the planet that is the planet we live on, the only one known to have life. (Choices: Mercury; Jupiter; Earth; Mars.)

  Answer: Earth.

  A student who picks "Jupiter" usually confused the largest gas giant with the ringed one.

Try these practice questions

1. Tonight the moon appears completely dark from Earth. What phase is the moon in?

   1. First quarter
   2. New moon
   3. Last quarter
   4. Full moon

2. Which moon phase is it when the whole lit side of the moon faces Earth?

   1. Full moon
   2. New moon
   3. First quarter
   4. Last quarter

3. Tonight more than half the moon is lit and the lit part is shrinking. What phase is the moon in?

   1. Waning gibbous
   2. Full moon
   3. New moon
   4. First quarter

4. Which moon phase is it when exactly half of the moon’s disk looks lit and the lit part is growing?

   1. Last quarter
   2. Full moon
   3. First quarter
   4. New moon

Answer key

1. New moon — When the moon appears completely dark from Earth, the moon is at new moon. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.
2. Full moon — When the whole lit side of the moon faces Earth, the moon is at full moon. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.
3. Waning gibbous — When more than half the moon is lit and the lit part is shrinking, the moon is at waning gibbous. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.
4. First quarter — When exactly half of the moon’s disk looks lit and the lit part is growing, the moon is at first quarter. Phases come from how much of the moon's sunlit half we can see from Earth — the moon is always half lit, and Earth's shadow is not what causes phases.

Keep practicing

The fastest way to build confidence is a few questions at a time, with feedback on each answer. Start with Space & Solar System practice for grade 3, where every question comes with a step-by-step explanation.

More from BAMS Academy:

• All 3rd grade science topics
• Matter & Energy practice
• Ecosystems practice
• BAMS Academy science practice by grade
• Every 3rd grade subject