This is due to the fact that there is a kind of substance at the bottom of the ocean which the water cannot penetrate, in spite of the tremendous pressure which the great body of deep water exerts. In all places where the bottom of the ocean has a covering which water can sink into it does so, but there are such a few places where this is possible, by comparison, that the amount that gets out that way is not noticeable. This water, if it can keep on going, will eventually reach the inside of the earth, where it is red hot, and is turned into steam. Where Does the Water in the Ocean Go at Low Tide? To get to the answer of this you must know something about the tides. The tide is caused by the pull of the moon on the waters in the ocean. The moon revolves about the earth once each day and has the ability to draw up the waters in the ocean toward it, as we have seen in our study of the tides. Now, when it is high tide in one place it is low tide in another. The moon does not make more water, but only pulls it toward it from side to side. When it is low tide where we are the water has simply moved as a body toward the place where it is high tide. The tides act a good deal like a see-saw, except that they move from side to side instead of up and down. When one end of the see-saw goes up the other end goes down, and when the “down” end comes up the other end goes down. So the answer to your question really is that at low tide the water which made it high tide a few hours before has gone to some place where it is at that moment high tide. Why Does the Ocean Look Blue at Times and at Other Times Green? Sometimes when we look at the ocean from the pavilion or while on the sand of our favorite bathing beach the water in the ocean looks very beautifully blue, and on other days will look dark green from the same point. Why is it? If you will stop to think that at night when there is no moon or other light the water in the ocean looks black, I think you will soon be on the right track to answer the question yourself. When the sky is blue--the kind of blue we like to see in the sky when we are at the beach--the water in the ocean is blue, because the sea reflects the color of the sky, and when the sky is overcast and gray the color reflected by the sea will be gray also.