Fluids (Humans vs. Cars)
If Harvin didn't write this, then I don't know who did.
Thesis
Also known as: Introduction
Okay, that was too simple. Fluids are everywhere, and we usually don't care. But fluids being everywhere is a good thing, because otherwise there would be no life. Fluids enable our bodies to operate, and provide vehicles with gas to run off of and oil to keep their engines running smoothly. There are many things fluids can do, and I use many because fluids cannot cook, clean your room, or do your laundry...or can they? Three proofs of fluids in action will be listed (because you know, three!). Here, it will be explained how fluids provide mobility, power, and protection to life and machinery. And no, some heavily viscous extraterrestrial fluid does not coat your car and absorb heavy bumps. That's insane.
Mobility
Cochlear fluid, steering wheel fluid, tears, and xenon gas.
Power
Blood, gasoline, and air.
Protection
Synovial fluid, cerebro-spinal fluid, motor oil, hydraulic fluid, engine coolant, and transmission fluid.
I. Mobility
Ever wonder how that steering wheel rotates so smoothly? Well, an aptly named fluid called steering wheel fluid makes the steering of the steering wheel so...ahem, fluid.
Also, try spinning on a desk chair with wheels. You'll feel what you see is rotating. Cochlear fluid, which is in the cochlea of the vestibular system, maintains balance. You spun around, so the fluid's function is disrupted until it re-adjusts in a few seconds. You should (not!) be ashamed of...actually, let's not go there. (That spinning thing is called vertigo, by the way.)
Finally, tears help clean the area around the tear ducts near the eye, increasing visibility. Xenon gas serves the same function in the light bulbs on the front of the cars (except for the really old ones), emitting light at night to show you the way.
II. Power
Gasoline (or gas, as most people insist) is a power source for millions of non-organic engines (sorry, brain!), which generate electricity to power homes and cars alike. This is great, as without the gas, we could not drive to places it only takes a minute to walk to, or sit on the couch and lie like a zombie while the television is showing stuff with embedded laughing-audience soundbytes. Gasoline is amazing, don't you think?
Air is a universal (actually worldwide, since the universe is a vacuum) fluid. The waste product of plants, it keeps biotic elements alive and wind turbines spinning. There's not much to say about it, but without air, there is no life. Then again, modern society takes it for granted.
III. Protection
For cars, there's more variety. We still don't get awesome thick alien fluid coats, but we do get motor oil. That's the stuff you dump into your engine (well, not quite) to reduce friction between moving parts, averting damage. Quite similar to synovial fluid, right? We then have hydraulic fluid. This helps the car stop during motion by using hydraulic pressure to squeeze the brake shoes against the wheels. Now, you no longer have to ram into cars! (If you thought that was funny, well...) Engine coolant is a fluid that cools down the engine (!) by absorbing heat and venting it out of the car. Otherwise, overheating can break down your car, so you can no longer use your car to reach the place that is a typical two-minute walk, which is a waste of gas. Come to think about it, walking is also a waste of gas. Finally, to protect your car, transmission fluid is quite interesting. It helps the car move forward with the weight of the car and its passengers. Oh, and guess what? It's quite the feat to push a two-ton (~1800 kg) car, so thank transmission fluid.