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bazinga818

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  1. bazinga818
    It was first Aristotle who discovered what is now known as the Mpemba effect: that hot water actually freezes faster than cold water. Scientists have struggled to explain this for years, until recently.

    We all know that "water" is made up of two hydrogen atoms and an oxygen atom, more accurately known as H20. Cold water is made up of short hydrogen bonds and long O-H covalent bonds, while the opposite is true for warm water. It is these hydrogen bonds that act weirdly and have drawn the attention of scientists.

    Some strange, unexplainable facts about these hydrogen bonds:
    1. Although they're generally weaker than covalent bonds, they are stronger than the "van der Waals" force that is the sum of all attractive forces between molecules.
    2. Chemists have suspected for awhile now that it is these hydrogen bonds that give water some of its weirder properties, such as allowing its boiling point to be so much higher than other liquids of similar molecular make-up. The hydrogen bonds hold it together very well.

    Anyway, though the hydrogen bonds bring water molecules into close proximity, the molecules are naturally repulsed by each other and as a result stretch away from each other and store energy, increasing heat.

    When the molecules shrink again and lose their energy, they begin to cool quickly as a result. Voila! The Mpemba effect.

    That was a simplified explanation from someone who hasn't touched Chemistry in two years, so I apologize if any of it is incorrect. Hope it gave you some insight, at least!

    Thanks for reading. Until next time,

    bazinga818
  2. bazinga818
    Recently (on a much cooler day), I discovered something while driving to volleyball practice at night. It was chilly so I had the heat on in my car, but just on low. Upon turning on the highway, I suddenly noticed that the heat seemed to have been turned up! That wasn't right, how could it do that on its own?! I double checked it, but the switch hadn't moved; the heat was still on the lowest setting.

    So why did it feel like hot air was blowing twice as fast into my face? Well, when I thought about it, the answer was simple: inertia. As the car accelerates forward (as it does when entering a highway), the objects - including hot air - inside the car want to stay put. This is the same reason why you feel thrust forward when you slam on the breaks, or slammed against the wall when you make a sharp turn. Your body wants to keep moving in a straight line due to inertia (as Newton says, "an object in motion tends to stay in motion").

    So, what does this have to do with the hot air in my car? Well, it too has inertia and wants to stay at rest unless acted upon by an outside force, so when I accelerated onto the highway, the hot air stayed in place. Since the car itself was accelerating forward while the air stayed put, it made it feel like the hot air setting had been turned up as it blasted in my face. In reality, it was me (and the car) accelerating into the hot air.

    Anyway, I thought this was pretty cool. Hopefully you thought so too! Thanks for reading.

    Until next time,

    bazinga818
  3. bazinga818
    As much as I'd like to tell you I've figured out all the physics of being invisible and how to acquire it as a superpower, I would be lying. To add insult to injury, this post isn't even about the physics of invisibility, but rather about why true invisibility is an impossibility due to the laws of physics. So if you don't want all your dreams of becoming a superhero with powers of invisibility to be crushed, it would be advisible to stop reading here! To everyone sticking around, be prepared to have your mind blown.

    To be truly invisible is to have light pass through you. You are still a solid being, but no one can see you because light passes through you rather than reflecting off of you. So as not to freak passersby out, it's assumed you would have to be naked pretty much all the time, and never carry anything on you - otherwise people would see floating clothes and objects.

    Naked outside in the middle of winter? And if it rains, the drops would bounce off of you, making your outline visible. This would happen eventually just with dust particles that collect on your skin too. Not to mention constantly having to dodge people and making sure you don't get run over by cars. Sounds fun so far.

    So, now on the physics mind-blowing part. What do you think the world would look like if you were invisible? The answer? Nothing. You see things because light bounces off of them and reflects in your eyes, right? That's why we can't see in the dark; there's no light. Well, if you were invisible, by definition light would pass through you - so images couldn't be reflected in your retinas for your brain to interpret and turn right-side up.

    I deeply apologize if I have ruined any of your fantasies, reader. But, if invisibility were a possibility, you wouldn't be able to see anything or anyone any more than they could see you. You would be blind. Trust me - I wasn't happy about it either.

    To those of you who are impartial to the subject of superpowers, I hope you enjoyed this blog post! Thanks for reading, and until next time:
  5. bazinga818
    Hi again, here to talk a little about the physics behind roller coasters!

    Something you might not know, or maybe you knew it on some level but never really thought about it - roller coasters aren't propelled along the ups and downs of the ride - they don't use an engine. They're only pulled to the top of the first hill; in order to get through the rest, the carts have to have enough forward momentum to get over the hills and/or through the loops.

    It all depends on the conversion of kinetic energy to potential energy and vice versa. Potential energy, given by the equation Pe = mgh, is at a maximum when the roller coaster is at the top of a hill, since it's height is the greatest. As it starts traveling down the hill, it's Pe is transfered into kinetic energy (Ke), given by (1/2)mv^2. Kinetic energy is at its maximum at the bottom of the hill because this is where it has its highest velocity, high enough to get the roller coaster up and over the next hill. In turn, then, the roller coaster's hills must be high enough to allow for a fast enough velocity when the cart reaches the bottom in order to get it over the next hill. Of course, it would make sense then that when Ke is at its maximum, Pe is at its minimum and vice versa. Crazy, right? Physics is bomb.

    You might be wondering how the ride runs smoothly without an engine on the cart, and how it stops when you get to the end (or rather, the beginning) of the track. Well, the wheels offer a lot of help - there are three sets of them. Running wheels guide the coaster on the track, friction wheels control lateral motion (movement to either side of the track), and a final set of wheels keeps the coaster on the track even if it's inverted. Compressed air brakes are what stop the car as the ride ends.

    So there's a bit about the physics behind roller coasters! If this blog post freaked you out a little when you realized roller coasters don't actually have an engine and we're basically on our own in the cart from beginning to end, don't worry. Riding roller coasters is actually more safe than most regular activities, like playing sports or riding your bike. The engineers that design them and the Amusement park owners who hire these engineers make sure of that - otherwise they'd be in for some pretty serious lawsuits.

    Thanks for reading! Until next time,

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