字幕表 動画を再生する
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[♪ INTRO]
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Hi there! It's snack time here at the Fort,
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so Squeaks and I are taking a quick break from our busy day to eat.
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[Squeaks squeaks.]
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Oh, I brought something new for a snack today, Squeaks.
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I've brought some hard-boiled eggs.
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I can crunch up the shell a bit, then peel it off with my hands…
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and then a little sprinkle of salt for flavor, and yum!
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[Squeaks squeaks]
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Oh, that's true, Squeaks!
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Hard-boiled eggs are quite a bit different from raw ones.
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They might look the same on the outside, but boiling an egg
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changes what we find inside the shell.
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When you crack open a raw egg, there's a clear, goopy, liquid part,
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called the egg white, and a smaller circle of yellow liquid,
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called the yolk.
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But take a look at my hard-boiled egg.
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What do you notice about it?
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[Squeaks squeaks]
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Oh yeah, the egg is solid!
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The egg white has turned white and firmed up into the shape of, well, an egg.
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And inside of it, we can see that the yolk has become
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a solid, yellow circle, with a kind of crumbly texture.
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[Squeaks squeaks]
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Well, Squeaks, the inside of this egg became solid when I boiled it.
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Cooking food in different ways, like boiling,
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can change a lot about them.
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When you boil food, you're heating that food up a lot
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by sticking it into really hot water.
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And that can do some really strange things to food:
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carrots get softer, butter and ice cream melt, and eggs,
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well, they get harder and tougher.
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Why do you think that is, Squeaks?
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[Squeaks squeaks]
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Yeah, it is a tough question.
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How about this: what do we know about eggs?
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[Squeaks squeaks]
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They are really yummy!
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And they're also really good for us. Do you remember why?
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[Squeaks squeaks]
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That's right! They are full of protein!
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And proteins are a kind of nutrient that we need!
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[Squeaks squeaks]
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That's right Squeaks!—proteins can help people to grow strong muscles.
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And they're also why cooked eggs are hard!
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If you had a really powerful microscope, you could actually
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zoom in and see all the proteins inside a raw egg!
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They would kind of look like folded laundry floating in water.
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But when you boil the egg, the heat makes the proteins unfold.
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And the parts that unfold are really sticky —
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so when the unfolded proteins bump into each other, they get stuck!
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After about 12 minutes, most of the nicely folded proteins
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end up stuck together into big, messy clumps.
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And then if you zoomed back out, you'd see that
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all those clumpy proteins make a solid egg.
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Now, what do you think will happen to our solid egg when it cools back down?
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[Squeaks squeaks]
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Ah you got it! Even though the heat is gone,
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the proteins stay stuck together, so the egg stays solid.
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That means you can't "uncook" an egg by putting it in ice.
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Once it's solid, it stays that way.
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Ooo, but what if I took the egg out earlier —
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like, after just five or six minutes?
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[Squeaks squeaks]
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That's right! It takes time for the proteins to unfold and stick together.
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So, if you pull the egg out of the water earlier,
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it's somewhere in between goopy and solid.
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The longer we boil and heat an egg, the more proteins
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can clump together, and the firmer the inside of the egg becomes.
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Some people actually choose to pull their eggs out earlier,
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because they like the middles of their eggs to be a bit runny!
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They call them “soft-boiled eggs”.
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[Squeaks squeaks]
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Ooo they do sound yummy, don't they? You want to try making some?
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[Squeaks squeaks]
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Let's do it!
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Cooking things can make some big changes to your foods,
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so it's a great way to try some at home experiments.
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With a grown-up's help, you can try soft-boiling
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and hard-boiling eggs, too, and observe the different textures.
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I wonder which you'll think is tastiest!
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Good luck with your experiments!
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And remember, if you'd like to keep exploring with me, Squeaks,
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Mister Brown, and all of our friends, make sure to hit the subscribe button.
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We'll see you next time, here at the Fort.
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[♪ OUTRO]
