At any ocean beach you can see the water rise up toward high tide.Something is pulling the water up. We now know that the moon is doing the pulling.How can it pull?We call the pull gravitation.All matter everywhere pulls all other matter everywhere.The bigger the object,the greater the pull.The moon is big enough to pull the earth,and it pulls the water on the earth.The moon pulls the water facing the moon.When you see high tide,you know that the moon is pulling the water up.