SCUBA diver. Photo Credit: wisegeek.com
The underwater world is beautiful and mysterious and as it makes up most of the livable volume on this planet it’s natural that humans would be interested in exploring it. SCUBA diving is one of the easiest and most accessible ways to explore the world under the waves. Getting humans to stay alive and comfortable for any length of time requires some pretty intense engineering.
The big problem is that humans need air. So SCUBA divers carry on their backs tanks of compressed air that they breathe for the length of the dive. The more air a diver can bring with them the longer they can stay under. The divers could either take larger tanks or try and pack more air into the tanks they already have. Really large tanks are impractically heavy and expensive so that option is out. That leaves packing more air into the tank, as more air is added the pressure increases because, for standard conditions, air follows the ideal gas law, PV=mRT. Where “V” is the volume of the tank, so that’s going to stay the same, R is the gas constant, T is the temperature which will stay constant as long as it’s filled slowly. This leaves P, the pressure of the tank. Modern SCUBA tanks are filled up to 3000 psi. That’s 3000 pounds of force on every square inch of the inside surface of the tank, or a large elephant standing on every 2″x2″ square of interior surface area. It takes some serious engineering to handle that without exploding.
Keeping an open mind, and being aware of the engineering that goes into many of the things that allow humans to explore where they could never go before, from the ocean to outer space is important. Advances in materials, mathematics, computers, and physics keep pushing the boundaries so that things once thought impossible become commonplace. Keep an open mind and keep learning, the future is going to be unimaginably incredible!
Rock climbing. Photo Credit: asme.berkley.edu
Rock climbing is becoming more and more popular as gyms pop up all over Southern California. This sport, like all sports, has many components that have been analyzed and optimized by engineers. Rock climbing brings its own unique challenges, most of all the balance between safety and weight. The more safety gear a climber uses the heavier they are and the more likely they will get tired and make a crucial mistake.
Climbing ropes are the major staple for safety gear. A climbing rope must be strong enough to catch a falling climber, tough enough to withstand almost constant rubbing against rough rocks, and still stretch enough so that the climber isn’t injured by a quick stop from a long fall. This is quite a bill for any rope to withstand but climbing rope does the job incredibly well. For a class project, standard nylon rock climbing rope was tested and compared to nylon 550 paracord and standard polypropylene utility rope. The differences were very apparent. While the paracord and utility rope broke fairly easily the climbing rope withstood more weight and stretched beyond the range of the testing machine. Try as we might we could not break the climbing rope within the range of motion that we had. This rope had a few interesting properties that led to its great success. First there was a protective casing of a tough material that could resist abrasion very well, then within, in the load carrying section the fibers had a special weave. This weave allowed the rope to stretch very far without breaking and slowly load the fibers that made up the rope. Some engineer did their job very well.
The very act of rock climbing can be helped by a brief engineering analysis. First off is conservation of energy. A climber’s muscles have a limited amount of energy in them so that energy needs to be saved for actual motion on the rock. When a climber is hanging on the rock, looking for the next hold or clipping in the rope their arms are fully extended allowing the weight of their bodies to be held by their bones, a rigid structure, rather than their muscles, an energy devouring structure. Another concept is as simple as balance, when a climber can just hang on a rock rather than resist swing or spin they are in a low energy state, even if this means that they are horizontal to the ground. A trick for this is being aware of your own center of mass as a climber and ensuring that it is perpendicular to the hold surface.
The more a climber can think about the physics of climbing the more energy they will be able to conserve and the better technique they will have.
Runner Running. Photo Credit: OpenSim.Stanford.edu
Sports have been an integral part of the human experience as long as history has been recorded. We’ve constantly been inventing new games and new ways to play the oldest of games. In recent years engineers have been directing their industrious creativity towards this growing field. These engineers have played such a major role in the sporting world that regulations have been put in place to keep athleticism and not technology at the forefront of sporting competitions, especially international ones. For example, advances in fluid dynamics have led to the creation of new swim suits and FINA, the Olympic swimwear regulator.
The base of most sports is the act of running, therefore if running could be made more efficient a huge number of sports could be impacted. There are three main factors that can limit a runner: heat dissipation, drag reduction, and impact absorption. In the next few paragraphs we’ll look into a few approaches to address these issues and make running more efficient.
First off is heat dissipation, or cooling off. Humans are historically good at this because our ancestors were persistence hunters, meaning we’d chase down animals until they were so tired they just gave up. For this to happen we’d have to be way better at staying cool then the animals were. In fact occasionally humans can beat horses in long distance races due to our superior cooling bodies. This just goes to show how important cooling is to distance running. Current running attire is designed to be light and breathable, two very important features. There are also the additions of reflective surfaces to prevent heat absorbed from the sun, like the shiny sunshades that protect cars from getting too hot. This in addition to moisture absorption and evaporative cooling could make running clothes into wearable swamp coolers.
Next is drag reduction. If a jogger is running and the air is still, there really isn’t much drag to consider. However the air is rarely ever stationary for the entirety of a race. If you’ve ever stood up in a strong wind you understand how much it can push you. There are ways to reduce this. The human body when running is not very streamlined, the runner presents the full width of the torso to the oncoming wind. When engineers are reducing drag for objects like this they tend to add textures and dents to the surface, like the surface of a golf ball. This creates turbulence to reduce flow separation and therefore reduce drag. This technology could be added to runner’s apparel and reduce the overall drag they would experience.
Finally impact reduction is key for any athletic event because impact causes injuries and takes players out of the game. Here we can delve a bit into shear thinning fluids. These are liquids like hair gel that don’t flow easily when they’re just sitting there but when they are moved they become more fluid. Imagine adding a little pocket of this kind of fluid to the heel of a shoe, on impact the fluid would thin and reduce the striking force. The synovial fluid in the knee is another example of a shear thinning fluid and it is used to lubricate the knee and absorb some impact. Traditional impact reduction using soft rubberized soles work well, this fluid would only help in addition to those soles.
The field of sports engineering is getting more and more publicity as technology increases. These are just three directions that research could go. The future of sports will be quite different and safer with the introduction of the engineering mindset.