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9th grade · Science · Unit 21 of 28

Moon, Tides & Seasons

Cycles in the sky: phases, eclipses, tides and seasons.

What your child practices

Practices explaining the repeating cycles of moon phases, eclipses, tides and seasons, and how gravity and Kepler's laws describe the orbits of the moon, planets and satellites.

New York State Learning Standards learning standard: HS-ESS1-7; HS-ESS1-4 · the cycles of moon phases, eclipses, tides and seasons, and the motion of orbiting objects

How we explain it

Children can open this short lesson before they practice.

  1. A solar eclipse happens only at new moon; a lunar eclipse only at full moon.
  2. Tides come mainly from the Moon’s gravity.
  3. Seasons are opposite in the two hemispheres because of Earth’s tilt. Gravity governs all orbits.

Example: When it is winter in the Northern Hemisphere, what season is it in the Southern Hemisphere? When one hemisphere tilts away from the Sun, the other tilts toward it. Answer: summer

Moon, Tides & Seasons in New York

In the New York State Learning Standards, this is unit 21 of 28 in 9th grade Science, after Engineering for Sustainability and before Stars & the Universe.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    When it is summer in New York, in Australia it is…

    • spring
    • fall
    • summer
    • winter

  2. Question 2

    Ocean tides are caused mainly by…

    • earthquakes
    • wind
    • the moon's gravity
    • the sun's light

  3. Question 3

    A solar eclipse can only happen during a…

    • waning gibbous moon
    • new moon
    • full moon
    • first quarter moon

  4. Question 4

    A year is the time it takes Earth to…

    • spin once on its axis
    • orbit the moon
    • go through one moon phase
    • orbit the sun once

  5. Question 5

    The moon's phases are caused by…

    • Earth's shadow on the moon
    • the moon changing shape
    • clouds covering it
    • how much of its lit half we see from Earth

  6. Question 6

    A satellite in a lower orbit travels…

    • backward
    • slower than one in a higher orbit
    • at the same speed as all satellites
    • faster than one in a higher orbit

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