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Tides Worksheet
By the end you will: explain how the Moon and Sun raise two tidal bulges, and when spring and neap tides happen.
A. Explore with the simulation
Press Play and watch Mumbai. How many high tides come in a day? How far apart are they?
Turn off the Moon's pull, keeping the Sun's. What happens to the tides? Then switch them the other way round.
Watch the Moon's phase. At which phases are the tides biggest (spring tides), and smallest (neap tides)?
B. Work it out
High tide at Mumbai is at 4:00 am today. Roughly when are the next two high tides?
The Sun's tidal pull is about 0.46 of the Moon's. Find the size of spring and neap tides compared with the Moon's alone.
C. Think it through
Why is there a high tide on the side of Earth facing away from the Moon too?
Answer key (for teachers and parents)
- Two high tides (and two low tides) a day, about 12 hours 25 minutes apart.
- With only the Sun, the tides are less than half as big. With only the Moon, they are bigger: the Moon makes most of the tide.
- Spring tides at New Moon and Full Moon, when Sun and Moon line up. Neap tides at the half Moons, when they pull at right angles.
- About 4:25 pm today and about 4:50 am tomorrow.
- Spring: 1 + 0.46 = 1.46 times. Neap: 1 − 0.46 = 0.54 times.
- The Moon pulls the near side water most, Earth's centre less and the far side water least. So the far side water is 'left behind', making a second bulge.
Free to print and share for teaching. Made with the interactive simulation at jugnix.com/simulations/tides.