TedEd: How rollercoasters affect your body

A TedEd by Brian D. Avery

Rollercoasters used to be much more dangerous. In 1895, crowds watched on the Coney Island boardwalk as the Flip Flap Railway took passengers for the first time. It was the first ever looping rollercoaster, but its thrills came at a price. People suffered neck injury and whiplash, and in severe cases, were ejected. Today, we can have far more thrilling rides without such dangers. How? Rollercoasters are operated using gravitational force, building potential energy as they go up, and releasing kinetic energy as they go down. But early designers were so concerned with making sure the cars didn't get stuck halfway up that they overcompensated. They failed to account for the fact that gravity affects your body as well. G-forces are the units used by most people to describe the amount of gravitational force, with 1G being normal gravity. Today, we know that bodies can handle around 5G's, whereas old rollercoasters were up around 12G's. At that amount, blood rushes to different parts of the body, causing blackouts, dizziness, and crimson vision. At negative G's riders become weightless, potentially making them fly out without the proper precautions. Modern straps and buckles have largely solved this problem, and there are also no sharp turns, which prevent whiplash and back pain. Increased G-forces also multiply weight, and sturdier rails have also allowed for better rides.

TedEd: How does laser eye surgery work?

A TedEd by Dan Reinstein

 

In 1948, a Spanish ophthalmologist named José Ignacio Barraquer Moner decided to create an eye surgery that would eliminate external reliance. His procedure involved cutting off a patient's cornea and dunking it in liquid nitrogen. When it froze, he would use a miniature lathe to shape it, then sew it back onto the rest of the eye. The process was called keratomileusis, using the Greek words for carving and cornea. His surgery fixed what are called refractive errors. The cornea and lens work together to focus incoming light on the retina so that we can see. However, many small errors can unbalance this system. Myopia, or short-sightedness, occurs when the cornea focuses light just short of the retina. The opposite occurs with hyperopia, or far-sightedness. In Asigmatism, the cornea creates two different curves that focus the light in two different places. Even in people with normal eyes, the lens proteins grow as we age, causing presbyopia, or aging eyes. By our mid-40's, the lens starts having problems focusing, which are solved by glasses that refract light to the proper angle. Today, scientists use a far less invasive procedure involving excimer lasers to fix the corneas. The lasers accomplish the task by heating and evaporating parts of the cornea without hurting the eye. This is known as photoablation. To begin the process, doctors shave away a bit of the top of the cornea with a knife or lasers. Then, the laser can reshape the corneal bed to the proper shape. This usually takes less than 30 seconds per eye, after which the top is put back on and heals within hours. The name for this procedure is "laser in-situ keratomileusis", where in-situ stands for "on site". It is more commonly known as LASIK. This does come with risks, such as permanent blurriness, but this is extremely unlikely. There are also more accurate procedures called SMILE that use even smaller lasers. We can also cure aging eyes with this process. The doctors change one eye to be slightly far-sighted and the other eye to be near-sighted. The eyes adjust so that you can see from both distances.

TedEd: The dangers of mixing drugs

A TedEd by Céline Valéry

What's wrong with taking cholesterol medication with juice, ankle pain drugs with alcohol, and blood thinners with aspirin? Taking these things together causes side effects that could, in severe cases, cause injury or death. There are two ways that this can happen. Two substances can interact directly, or one can influence the way the body processes the other. With aspirin and blood thinners, both of them prevent blood clots from forming. Blood thinners prevent clotting factors from forming, and aspirin breaks the clots apart. Alone, these medications do their job. But together, they can have a big enough effect to cause internal bleeding. The other two reactions have to do with enzymes from the liver that break down substances. In the case of grapefruit juice and cholesterol, both of them require the same enzyme to break down, which means that the cholesterol medication is in the blood stream for longer. This could cause kidney failure. Alcohol also alters enzyme activity. Many pain relievers have a substance that creates a toxic by product when broken down. Usually, the amount is not deadly. But when the enzymes are affected by alcohol, they produce more of the toxic substance, potentially causing liver damage. Still, scientists are researching new drugs as they come out, hopefully preventing fatal drug interactions before they happen.

Scythe

Scythe

By Neal Shusterman

Read in 8th grade

Book 1 in series

Read book 2! Thunderhead (coming soon)

Read book 3! The Toll

    First book in Arc of a Scythe series. It takes place in a world past death, without disease or aging. Pain nanites can regrow limbs, and if you are killed in an accident, you are revived. There is no politics, because the world is taken care of by an AI called the Thunderhead. It keeps the world running, and every move is calculated so it is never wrong. Its mission: Protect humanity. At all costs. So how is the population kept in check if no one dies? Scythedom. This group is beholden to no laws, and the Thunderhead must stay out of its way as a part of its fundamental programming. These people go around and glean people, and can also grant immunity for a year. They can take whatever they want, and everyone fears/respects them. 

    One day, Scythe Faraday shows up at Citra Terranova's house and eats a meal. Afterward, he asks for a knife. Her family is terrified, but he gleans the person next door and grants Citra's mother immunity. Rowan Damisch is sitting at his friend Tyger's bedside after he splatted from hundreds of feet up. At school, Faraday shows up to glean the high school quarterback. Rowan stays with him for emotional support. Faraday notes his compassion. Later, he is ridiculed, accused of being with the quarterback for immunity.