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CAST — California Science Test Venus and Mars — practice questions

Explore 5 free Venus and Mars questions in CAST — California Science Test Science. Open each question or exercise to read its content, reference answers and available explanation.

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Venus and Mars questions and exercises with answers

Showing questions 1–5 of 5.

Mars looks distinctly red through a telescope. What gives it that color?Read the answer and worked solution →Venus turns on its axis once every 243 days. What else is odd about that turning?Read the answer and worked solution →Venus goes around the Sun in 225 Earth days and turns once in 243. What follows from those two figures?Read the answer and worked solution →Magellan mapped Venus with radar. On those maps, what do the brighter areas mean?Read the answer and worked solution →Tap the bigger of the two figuresRead the answer and worked solution →

Worked practice questions

Mars looks distinctly red through a telescope. What gives it that color?

  1. Iron oxides in its soil
  2. Red dust in its clouds
  3. Warm rock under ice
  4. Sulfur across its poles
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Correct answer: A. Iron oxides in its soil

1. The color comes from the ground itself, not from the thin air above it. 2. Iron oxides in the martian soil give the surface its rusty red tone. 3. That color is why many early cultures linked the planet with war and blood. _Source: OpenStax Astronomy (CC BY 4.0), section 10.1 The Nearest Planets: An Overview_

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Venus turns on its axis once every 243 days. What else is odd about that turning?

  1. It runs top to bottom
  2. It runs east to west
  3. It stops twice a year
  4. It speeds up at noon
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Correct answer: B. It runs east to west

1. Radar bounced off Venus revealed both the rate and the direction of its spin. 2. The spin is retrograde, running east to west instead of west to east. 3. That backward turn may be the mark of a huge collision early in the planet's history. _Source: OpenStax Astronomy (CC BY 4.0), section 10.1 The Nearest Planets: An Overview_

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Venus goes around the Sun in 225 Earth days and turns once in 243. What follows from those two figures?

  1. Its year outlasts its own day
  2. It keeps one face to the Sun
  3. Its day outlasts its own year
  4. It has no seasons of any kind
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Correct answer: C. Its day outlasts its own year

1. A year is one trip around the Sun, which takes Venus 225 Earth days. 2. A day in the sense of one spin takes Venus 243 Earth days. 3. 243 is the larger of the two numbers. 4. So one spin of Venus lasts longer than one of its trips around the Sun. 5. That makes the Venusian day longer than the Venusian year. 6. The reversed option simply swaps the two numbers and gets the comparison backwards. 7. Keeping one face to the Sun would need the spin and the orbit to match, and 243 does not equal 225. 8. The time for the Sun to return to the same place in the sky works out to 117 Earth days. _Source: OpenStax Astronomy (CC BY 4.0), section 10.1 The Nearest Planets: An Overview_

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