评论
打印
Hi there!
大家好!
Squeaks and I were just talking about one of our favorite summer foods: Fruit salad!
我和吱吱刚刚在谈论我们最喜欢的夏季食物之一:水果沙拉!
Making a fruit salad is just a matter of taking pieces of fruitand mixing them all up in a bowl.
做水果沙拉就是把水果块放在碗里搅拌。
What can be hard is deciding what yummy fruits to include!
最难的是决定要放哪些美味的水果!
What would you like to add, Squeaks?
吱吱，你想要放那些水果?
Ooh, good choices.
哦,不错的选择。
Squeaks would make sure he had cherries and watermelon, while I’d pick…
吱吱确认他要樱桃和西瓜，而我则会选择……
Hmm, let’s see, pineapple and blueberries!
嗯，让我看看，菠萝和蓝莓!
Blueberries are my favorite parts of a fruit salad.
蓝莓是水果沙拉中我最喜欢的。
In fact, sometimes I eat all of the other fruit first, and save the blueberries for last.
事实上，有时我会先吃掉所有水果，把蓝莓留到最后。
It’s not really that hard to do, because the pieces that make up a fruit salad mixture are still there.
其实做起来并没有那么难，因为组成水果沙拉的各个部分仍然没变。
Mixing them together doesn’t change them!
把各种水果混合在一起并不会改变它们!
But sometimes, mixing two things together results in what’s called a chemical change.
但有时，两种物质混合在一起会导致所谓的化学变化。
During a chemical change, the things that get mixed together become something new!
在化学变化中，混合在一起的东西会变成新的东西!
So we can’t pull them apart very easily, like we can with the mixture of fruit in our fruit salad.
我们把它们分开不是很容易，就像我们在水果沙拉里混合水果一样。
Sure we can try to make a chemical change happen!
当然，我们可以尝试让化学变化发生!
This experiment will be super fun, and very messy, so it’s a good thing we’re outside.
这个实验会非常有趣，也会搞得乱糟糟，所以幸好我们在外面。
We’re going to make something that looks a lot like toothpaste…
我们要做一些看起来很像牙膏的东西……
and I think there’s going to be a lot of it — so much that an elephant could brush its teeth!
而且我认为会有很多——多到大象都能刷牙了!
Now, if you’re going to try this at home, it’s really important that you do this safely.
现在，如果你要在家里做这个实验，确保安全是非常重要的。
That means you need help from an adult, and some safety glasses or goggles.
这意味着你需要家长的帮助，以及一些安全眼镜或护目镜。
For this experiment we’re going to need an empty plastic bottle, a funnel, a measuring cup and spoon, some dry yeast, warm water, food coloring, and some liquid dish soap.
做这个实验，我们需要一个空的塑料瓶，一个漏斗，一个量杯和勺子，一些干酵母，温水，食用色素和一些洗洁精。
Finally, we’ll need something called hydrogen peroxide.
最后，我们需要一种叫过氧化氢的东西。
That’s right!
正确!
Sometimes adults will use hydrogen peroxide to kill germs, so you might have some at home.
有时成年人会使用过氧化氢来消杀细菌，所以你家里可能有一些。
Oh! And you might also want to do this experiment on a large tray or in a large tub.
噢!你可能还想在一个大托盘或大浴缸中做这个实验。
Ohh, you’ll see why, Squeaks!
哦，吱吱，你会知道为什么的!
Now, let’s get started.
现在，我们开始吧。
First thing — safety first!
第一件事——安全第一!
Glasses… on!
戴上眼镜!
Next, we’ll mix our yeast and warm water together and wait for at least 30 seconds.
接下来，我们将酵母和温水混合在一起，等待至少30秒。
It’s okay to wait a little longer, though, so let’s get the other part of the experiment ready.
不过，再等一段时间也没关系，所以让我们准备好实验的另一部分吧。
We’ll pour our hydrogen peroxide into the bottle using the funnel.
我们用漏斗把过氧化氢倒入瓶子里。
Next, we’ll add a few squirts of dish soap.
接下来，加几滴洗洁精。
And swirl the bottle so that everything mixes together.
旋转瓶子，让所有东西混合在一起。
Let’s check on our yeast.
让我们检查一下酵母。
Oh, look at our yeast mixture, Squeaks!
哦，吱吱，看看我们的酵母混合物!
What do you see?
你看到了什么?
Ooh, I do too!
哦，我也是!
The yeast and water mixture is kind of bubbly.
酵母和水的混合物有点起泡了。
I agree!
我同意!
While it is bubbly, it doesn’t look like toothpaste, and there’s not a lot of it.
虽然起气泡了，但看起来不像牙膏，而且牙膏的用量也不多。
And if we look at the bottle, we can see there’s nothing in there that looks like toothpaste, either.
如果我们看看这个瓶子，我们可以看到里面也没有什么看起来像牙膏的东西。
But I think we’re ready for our chemical change to happen!
但我认为我们已经准备好发生化学变化了!
We’ll quickly pour the yeast mixture into the bottle on the count of three.
数到三，我们迅速将酵母混合物倒入瓶中。
Ready?
准备好了吗?
One…Two…THREE!
一……二……三!
Oh, and look at all the foam!
哦，看看这些泡沫!
There’s SO MUCH of it!
有这么多!
What else do you notice about it?
你还注意到了什么?
Do you think it looks at all like what we started with?
你觉得它看起来像我们开始的时候吗?
Me neither!
我也不!
And look, there’s no way we could pick what we started with out of this mixture.
看，我们不可能从混合物中选择我们开始时放的物质。
Do you notice anything else?
你还注意到别的吗?
Ooh, yes!
哦,是的!
The bottle feels warm.
这个瓶子摸起来是热的。
And that warmth is a clue that a chemical reaction took place!
这种温度变化是发生化学反应的线索!
Some chemical reactions, like this one, release heat.
一些化学反应，比如这个，会释放热量。
And bubbles are also often a way to tell that a chemical reaction took place.
而气泡通常也是一种表明发生了化学反应的方式。
If we look closely at the foam, we can see that it’s made of TONS of tiny bubbles!
如果我们仔细观察泡沫，我们会发现它是由无数的小气泡组成的!
Another clue.
另一个线索。
So I’d say that we definitely had a chemical change take place in our experiment.
我想说我们的实验中肯定发生了化学变化。
We’ll leave our goggles on until we’re done getting cleaned up, Squeaks.
吱吱，在我们清理完之前，我们会一直戴着护目镜。
Then we can talk about what happened!
然后我们再谈谈发生了什么!
Let’s start by looking at what we started with:
让我们先看看我们开始时放的东西:
We had yeast, water, dish soap, food coloring, and hydrogen peroxide.
我们放了酵母、水、洗洁精、食用色素和过氧化氢。
And what we have now doesn’t look like any of those things.
而我们现在所拥有的一切与原来的这些都不一样。
A chemical change happened, so we can’t go back to what we started with!
发生了化学变化，所以我们无法回到开始的时候!
But some changes can be reversed.
但有些变化是可以逆转的。
If you put some water in the freezer, after a while it will freeze into solid ice.
如果你在冰箱里放一些水，过一会儿它就会冻成固态的冰。
And if you take that ice out and put it in the sun or on the counter for a little while, it will melt into liquid water again.
如果你把冰拿出来，放在太阳下或柜台上一会儿，它会再次融化成液态水。
So, you get back what you started with!
所以，你得到了最开始的东西!
But our chemical change isn’t reversible like that.
但是这个化学变化不是可逆的。
Our toothpaste won’t go back to being soap and yeast and everything else.
我们的牙膏不会再变成肥皂、酵母和其他东西了。
Can you think of any other changes that aren’t reversible?
你还能想到其他不可逆的变化吗?
Oh, yeah!
哦,耶!
When you heat up an egg, it goes from runny and gooey, to cooked and yummy.
当你加热鸡蛋时，它就会从流动粘稠的液体变成煮熟的美味。
But even if you don’t finish your breakfast and leave the egg out for a while, it stays cooked.
但即使你没有吃完早餐，把鸡蛋放在外面一段时间，它也会一直是煮好的状态。
The change wasn’t reversible.
这种变化是不可逆转的。
But speaking of yummy things, remember that fruit salad mixture we were talking about?
但说到美味，还记得我们之前说过的水果沙拉混合物吗?
I’d sure love some of that now.
我现在肯定很喜欢。
So let’s go and make some!
所以让我们去做一些吧!
Thanks for joining us here at The Fort!
感谢您观看我们在福特堡的节目!
If you want to keep learning and having fun with me, Squeaks, Mr. Brown, and all our other friends, be sure to hit the subscribe button, and we'll see you next time on SciShow Kids!
如果你想继续与我、吱吱、布朗先生以及我们所有的朋友一起学习、一起玩耍，一定要点击订阅按钮，我们下次《少儿科学秀》再见!
