Why the tides rise and fall

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Tidal arrows from the Moon and the Sun. Which raises bigger tides on Earth, the Moon or the Sun, by Bo's reading (NOAA)?

   • The Sun, since it is more massive
   • Neither; Earth's spin alone makes tides
   • They are exactly equal
   • The Moon; the Sun's tidal force is about half
2. 2.

   Why does the Moon raise bigger tides than the far more massive Sun, by Kira's reading (NOAA)?

   • The Moon is far closer, and tidal force drops fast with distance
   • The Sun is too hot to pull on water
   • The Sun pulls on land but not water
   • The Moon is more massive than the Sun
3. 3.

   Earth with ocean bulges drawn, the Moon to one side. How many tidal bulges does the Moon raise on Earth's oceans, by Jun's reading (NOAA)?

   • Four
   • Two: one facing the Moon, one opposite
   • One, facing the Moon
   • One, on the far side
4. 4.

   What forms the bulge on the side of Earth away from the Moon, by Luz's reading (NOAA)?

   • Inertia beats the Moon's weaker pull there
   • The Sun's gravity pushes that water outward from Earth
   • The Moon pulls hardest on that side
   • There is no far-side bulge

5. Read this first

   Use this

   Moon-phase calendar for one month.

6. 5.

   When do spring tides happen, by Noah's reading (NOAA)?

   • In March and April, as the spring season brings warmer seas
   • In the spring season
   • At new and full Moon, when the Sun, Moon and Earth line up
   • At first and third quarter
7. 6.

   When do neap tides happen, by Pia's reading (NOAA)?

   • When the Moon is closest to Earth and pulls the hardest on the sea
   • In winter
   • At new and full Moon
   • At first and third quarter, with the Sun and Moon at right angles
8. 7.

   How many sets of spring tides come in each lunar month, by Ren's reading (NOAA)?

   • Two
   • One, in the spring
   • Twelve, one a month through the year
   • Four
9. 8.

   About how far apart are the two high tides on most coasts, by Tala's reading (NOAA)?

   • Exactly 12 hours
   • 12 hours 25 minutes
   • Exactly 24 hours
   • 6 hours 12.5 minutes
10. 9.

    Clock face with a lunar day marked. How long is a lunar day, by Zee's reading (NOAA)?

    • 24 hours 50 minutes
    • 12 hours
    • Exactly 24 hours, the same as a solar day
    • 29.5 days
11. 10.

    Why is a lunar day longer than 24 hours, by Esme's reading (NOAA)?

    • Earth spins more slowly at night, so each day stretches out longer
    • The Moon spins backward
    • It is not; tides repeat each 24 hours
    • The Moon moves along its orbit, so Earth turns extra to catch up