TedEd: What happens when you have a concussion?

A TedEd by Clifford Robbins

Each year in the U.S., millions of athletes get concussions. A concussion occurs when the soft, fatty tissue of the brain receives a sudden jolt and bumps against the side of the hard skull. The brain is made up of tens of billions of neurons, which transfer electrical signals to communicate throughout the body via axons. Because these axons are long and thin, they are prone to breaking when collisions occur. This also releases toxins that kill other neurons nearby, causing more brain damage. This often results in problems with memory, mood, vision, sleep, and anxiety. Most of the time, sleep, rest, and a gradual return to activity heals most side effects of concussions. Sometimes, if people return to sports too quickly or don't rest, they can develop post-concussion syndrome, which has health implications years down the line. Researchers also found that frequent, small impacts can cause the brain to loose integrity in its axon bundles, leading to chronic traumatic encephalopathy, which can cause concussion-like symptoms along with dementia. This occurs due to a protein called tau, which is usually on microtubules supporting the axons. However, when impacted, they fall off and form clumps, impeding axon efficiency. Up 80% of concussions go undetected or unreported, and it's important to remember that our brains aren't invincible.

National Geographic: Will charging electric cars ever be as fast as pumping gas?

By Madeleine Stone

    One major obstacle to the adoption of electric vehicles is charging. Currently, they typically take around 30 minutes for an 80% charge, though this can vary with the size and charge rate of the battery. However, new lithium-ion and solid-state technologies being developed by companies could reduce those times to around 20 minutes.

    Current EV batteries are composed of lithium-ion cells that can store and release energy thousands of times. Each cell consists of a lithium cathode and a graphite anode with liquid electrolytes in the middle. When the battery is charged, lithium ions flow across the liquid from the cathode to the anode and fill up the graphite. The speed is determined by the rate at which ions flow across the liquid. But charging too fast can cause the battery to overheat, develop a lithium plate over the anode, or form dendrites that can cause the battery to explode. In fact, the capacity of the charging stations isn't the problem - the fastest chargers can already charge batteries at extremely high rates, but the batteries have limits on how quickly they can charge.

    One solution is alternative anode materials. Niobium, for instance, doesn't overheat or form lithium plates, but one downside is that it doesn't store as much energy per unit, making it infeasible for EVs for the time being. Another option is solid-state storage. These use solid electrolytes instead of liquid, preventing the possibility of fire, though these form dendrites at high charge rates. Both technologies are years in the future, but new research is bringing them ever closer.

    Once EVs have super-fast batteries, charging them will put a much larger strain on the electricity grid. If all of them are pulling 400 volts of energy at once, it will be hard to keep up, which is why most developers are opting to keep speeds at around 20 minute charging times. In addition, many people like to charge at their homes after work, when there is less strain on electricity, helping them reach full environmental potential.