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  • [♪INTRO]

  • If you've ever taken a science class, you've probably done some kind of at-home biology,

  • chemistry, or physics experiment.

  • And for good reason — a baking soda volcano is an easy way to get a hands-on look at how

  • the world works.

  • Plus you get to make a messtons of foam, red food coloringyour mom is like, “Why?”

  • But when it comes to understanding space, at-home experiments are a lot harder.

  • After all, space is a giant vacuum, which you can't exactly recreate in your basement.

  • And even if you could, you shouldn't.

  • One thing you can build at home, though, is a rocket.

  • Specifically, a hybrid rocket engine, which many engineers want to use to explore the

  • solar system.

  • All it takes are some basic household supplies and a little caution.

  • All rockets work by throwing something out the back to propel the rocket forward, and

  • hybrid rockets are no exception.

  • Like what we use in current rockets, they're a type of chemical engine, and the big ones

  • generate force with a giant, controlled explosion.

  • We'll do our best to make sure this experiment doesn't get all explode-y, but we will create

  • a smaller flame.

  • And like with a full-sized rocket, we'll make that fire using two basic components:

  • fuel and an oxidizer.

  • The fuel is whatever you're burning to propel your spacecraft forward, and the oxidizer

  • helps your fuel catch on fire.

  • Like the name suggests, this is often an oxygen-containing compound.

  • Current rocket engines will sometimes combine these elements in one solid, pre-mixed block

  • that's a solid engine.

  • Or, they might use liquid engines, which have separate liquid components that get mixed

  • as they go.

  • Hybrid engines are special because they use a combination of both solid fuel and liquid

  • or gas oxidizer.

  • Right now, these engines tend to have less thrust than the other models, so they haven't

  • been used on many missions.

  • A lot of those limitations have to do with how the fuel burnswhich is what you're

  • about to see for yourself.

  • So, we don't have a lab or a kitchen in this room, but we do on SciShow Kids, so I'm

  • going to go over to the SciShow Kids studio next door for a little bit of rocket science.

  • For our hybrid rocket, we're going to use some cylindrical fuelthis is a pasta

  • noodle, it's rigatoni, it's got calories in it.

  • You burn it to make yourself.

  • We're going to burn it to make a rocket.

  • And for our oxidizer, we're going to be using pure oxygen gas, which will be created

  • through a reaction between hydrogen peroxide and active yeast.

  • The yeast contains a protein called catalase, which will break down the hydrogen peroxide

  • into water and pure O2 gas.

  • Besides the pasta, hydrogen peroxide, and yeast, you'll also need a few other basic

  • staples: some safety goggles, a fire extinguisher just in case, and a lighter or a few matches,

  • and a small mason jar with a hole knocked in the lid.

  • Our jar is about 230 milliliters, or 8 fluid ounces, and the hole in the top is around

  • a third of a centimeter across.

  • The important part is that the noodle should fit over the hole without covering any of

  • the hole up, and without any of the hole escaping from around the noodle.

  • First, lay out all of your supplies ahead of time so you're ready to go once the reaction

  • starts.

  • Then, you fill your mason jar about three-quarters of the way with hydrogen peroxideor about

  • 175 milliliters.

  • Now, here comes the fun part.

  • Add a quarter of a teaspoon of yeast to your jar, and stir.

  • You should see some bubbles start to formthat's the pure oxygen.

  • Quickly place the lid on the jar, and place the noodle upright over the hole.

  • Thenget ready for itlight the top of the noodle on fire!

  • You should see a small column of flame rise up over the noodle as it burns.

  • There is your engine!

  • That's a pretty good engine!

  • Oooh!

  • There, it's going!

  • Oh my gosh.

  • Now it isn't producing much force, and any force it is making is directed into the table.

  • So the engine won't go anywhere, which is probably a good thing in this case given thatah,

  • large sizable chunk of it is on fire.

  • The reaction's either going to continue until the noodle is all burned up, or until

  • the chemical reaction with the yeast stops.

  • We're going to have to wait until that gets a little less hot.

  • The main limitation with hybrid rocket engines is that they just aren't very powerful compared

  • to other rocket types.

  • And a lot of that is because of how the fuel burns.

  • In our demo, the oxidizer flowed through the rigatoni-fuel, and it's basically the same

  • process in the real thing.

  • How fast the fuel burnsand how much thrust the engine produceshas to do with how

  • much oxidizer is moving through it.

  • If the oxidizer has just one hole to flow through, like with our noodle, it will only

  • burn a little fuel at a time, so it won't be very powerful.

  • The big challenge for engineers is figuring out how to shape the fuel so there's an

  • optimal flowenough so that it can propel a rocket efficiently, but not so much that

  • it burns through all the fuel all at once, which would just be an explosion.

  • Teams are working on it, though!

  • There's been more interest in developing hybrid rockets over the last few years.

  • And another cool thing about this demo, besides the column of fire, is that it kind of illustrates

  • why.

  • One advantage to this type of engine is that it's hard to accidentally blow up.

  • Not that I'm encouraging you to try.

  • But since the fuel and oxidizer are stored separately, there's a much lower risk of

  • accidental explosion compared to a solid engine, where everything is already blended together.

  • In these solid mixtures, the block can sometimes become damaged, which can lead to uneven firing.

  • And hybrid engines are less complicated than many liquid engines, since hybrids only have

  • one fluid component instead of two.

  • For our rocket, we didn't have to worry about continuously mixing fluids and hitting

  • the right ratios and flow rates.

  • There were fewer moving parts.

  • In the real world, these benefits translate to engines that could help us launch rockets

  • more safely and more cheaply than we are right now.

  • We just have to figure out how to give them some extra thrust.

  • Unfortunately, that probably isn't a problem we can solve with pasta and mason jars, so

  • we'll have to leave it to the experts.

  • Thanks for watching this episode of SciShow!

  • If you'd like to keep learning more about space, we have a channel where we unpack all

  • kinds of mysteries about our universeand the rockets that help us explore it.

  • You can learn more at youtube.com/scishowspace.

  • [♪OUTRO]

[♪INTRO]

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B1 中級

キッチンでロケットエンジンを作る方法(実験編 (How to Build a Rocket Engine in Your Kitchen (Experiment Episode))

  • 21 1
    robert に公開 2021 年 01 月 14 日
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