Jacob Dummeldinger, right, skips rocks into the ocean in a cove on Eagle Island during a recent visit to the island off the coast of South Harpswell last summer. Russ Dillingham / Sun Journal file photo

While we are in the height of summer and there is plenty of living stuff in the ocean to focus on, there is also a lot to learn about the physical aspects of the ocean. There are the waves, the temperature, the salinity and all of those oceanographic features. And there’s also the geology — the rocks around and under the ocean and how they played a role in its formation. I’ve tried to get my head around both physical oceanography and geology many times and it never seems to stick. But skipping rocks with my daughter recently brought a new kind of understanding.

Skipping rocks is a simple enough–seeming activity and can be learned pretty easily and done with myriad variations. The reasons why it works or doesn’t work, however, are more complicated and offer a new insight into both geology and oceanography. On the rocky side of things, the choice of rock is obviously a factor. The shape is often the first thing people think of — a nice flat rock ought to skip best. This is true because of a flat rock’s ability to skim over the surface of the water. But not every flat stone is a good skipper. The consistency of thickness matters as does the weight of the rock. If a rock is too heavy, it is hard to skip. In Maine, many of the seaside rocks are composed of multiple types of minerals with different textures and weights so that finding a smooth, regular rock with nice, rounded edges is not always easy. Take a close look at the next rock you try to skip and see how many different colors and textures you can see.

Water conditions play a large role as well. Calm, still water is the easiest, but it isn’t impossible to skip rocks in water with waves. In fact, you might end up getting more of a “jump” than a “skip” as a rock headed out horizontally gets pushed up by an incoming wave. This is a lesson in wave energy to be learned here about the forward motion of the top part of the wave. Surfers know this well as they try to catch the wave energy and ride it towards shore. When you try to skip against a wave, you have to give the rock a little extra oomph.

That gets to the technique required to skip a rock. Different people like to hold rocks in different ways, but one of the tried-and-true methods is to put the rock between your thumb and either your index or your third finger. Then, pivot your wrist back, pull your whole arm back along your side, and quickly snap your wrist and arm forward, releasing the rock. There is a great diagram of this technique here at artofmanliness.com/skills/how-to/how-to-skip-a-stone-an-illustrated-guide (although I’d argue that this isn’t just a manly skill). And I’m sure there are myriad videos out there that demonstrate it as well. Getting low down as you release the rock helps as well so that you can keep a minimum angle to the water.

If mastering the basics isn’t enough, you can vary the challenge to include things like furthest total distance, highest number of skips, greatest height of a single skip or who can skip the biggest, wackiest, misshapen rock. Whatever rock you try, conditions you test or challenge you attempt, each toss offers a way to learn something unexpected about some of the physical aspects of Maine’s seashore.

Susan Olcott is the director of operations at Maine Coast Fishermen’s Association.