Two Ocean Bulges

In the picture

1. 1A coastal point on the globe: it sits inside an ocean bulge.
2. 2An ocean bulge: a raised area of ocean aligned with the Moon.
3. 3The Moon: it keeps the two ocean bulges lined up toward and away from it.
4. 4The same coastal point half a turn later: it sits inside the opposite ocean bulge.

Examples

• A beach town sees the water climb the shore, then pull back, then climb again before night.
• A harbor’s boats float higher in the morning and again in the evening.

Quiz: Two Ocean Bulges (Age 12)

1. 1

   In one day, how many high tides and how many low tides does a coastal place get?

   • two high tides and two low tides
   • one high tide and one low tide
   • four high tides and four low tides
2. 2

   What keeps the two ocean bulges lined up in the direction of the Moon and opposite the Moon?

   • Earth’s spin
   • the Moon
   • the coastal place
3. 3

   A coastal point starts inside one ocean bulge. Where is it half a turn later?

   • halfway between the two ocean bulges
   • inside the opposite ocean bulge
   • inside the same ocean bulge

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.