Why do waves slide back into the ocean instead of being sucked into sand?

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Why do waves slide back into the ocean instead of being sucked into sand?

In: Physics

7 Answers

Anonymous 0 Comments

The sand a few centimeters down is already wet. So there is no space for more water. So it just flows back into the ocean. But a part of the water flows back through the sand indeed.

Anonymous 0 Comments

Sand has space between the grains that can be filled by either gas or a liquid, the sand in the shore is soaked to its limit.

Anonymous 0 Comments

It does both. Water takes the easiest path back to the lowest level it can. The water that soaks into the sand can’t move very fast. The water above it has nowhere to go, until the wave passes. Then it can just roll across the water that soaked into the sand and join with the ocean again.

Anonymous 0 Comments

The sand can only absorb so much water. That’s why when you walk on a beach there is very dry sand and as you get closer to the water it gets more wet and compacted. The sand closer to the water has soaked up all it can take and now the waves just move over it and back down to the ocean.

Anonymous 0 Comments

Haha haha imagine *all* of the ocean water getting sucked into the beaches, creating giant sponge-walls along the coasts.

Anonymous 0 Comments

While a lot of these answers are good, nobody has also pointed out one of the properties of water responsible for this. Aside from saturation in the sand, water molecules are cohesive—they like to stick to each other. This is due to hydrogen bonding in the molecules. Since water is “sticky” and likes to keep in touch, molecules can pull each other. This is why waves are able to pull the water back, as well as the reason (along with the adhesive nature of water, or the tendency to stick to other stuff) is why some water may run down the glass when you pour it.

Anonymous 0 Comments

It’s like spilling a large glass of water on the floor and trying to soak it all up with a towel that’s too small. The towel soaks in as much as it can, but after a while you’re just sloshing liquid around.