The potential energy of a (giant) pile of sand

Don't diss my awesome paint skills! It's too awesome for you to even comprehend its beauty!

So as we all know, us juniors had class day on Thursday at Kailua. Thankfully there wasn't as many jellyfishes as last year, but staying in the water for hours gets to be a little repetitive, so a few of us were burying a friend's legs in sand. We got it up to her knees, and even made a little seat for her so that she could sit comfortably as the weight of the sand slowly crushed her toes for an hour or two. Unfortunately, the water came up a LITTLE too close to the growing pile, continuously causing structural failure and the frantic piling of sand to replace and attempt to seal up the massively growing cracks. Then someone pointed out that this pile had a little physics going on.

Doesn't everyone think of Physics on a non-school day? Apparently us AP guys do, or anyone having to do a blog on it. That day, we gave many grains of sand a potential energy by placing them higher and higher from ground level (sand level?) in order to cover up our friend's legs. When the waves hit the pile and receded, they took some sand with them, giving the grains a velocity and reducing their potential energy until the water pushed them onto the beach or let them sink to the bottom of the ocean blue, causing us to give handfuls of sand potential energy to cover up for the losses. Eventually, some of us gave up, knowing that it was hopeless to keep trying, and the pile, in time, disappeared with the waves. At least we learned a few good lessons there, like not starting a sand pile next to the water...