So this set starts out blue

这一组最开始是蓝色的

This one starts out pink

这一组最开始是粉色的

And the final one is purple

最后一组则是紫色的

And every cylinder contains a few drops of sodium hydroxide

每一组柱形容器中都包含少许氢氧化钠

which is a base

这是一种碱

NaOH, sodium hydroxide NaOH

氢氧化钠

and it's a base

它是一种碱

So let's start with the basics

我们从基础开始考虑

What is an acid and a base?

酸和碱是什么

One definition is that

一种定义是

acids are compounds that donate a hydrogen ion

酸是一种化合物，它能贡献一个氢离子

or H plus

或者说H+

to another compound

给另一种化合物

and the compound that accepts that hydrogen ion is a base

而接受这个氢离子的化合物就是碱了

So acids are hydrogen ion donors

酸是贡献氢离子的物质

and bases are hydrogen ion acceptors

而碱则是接受氢离子的物质

Here are some examples

我举一些例子

Sodium hydroxide is a base

氢氧化钠是碱

It's used to make soap

能用于制造肥皂

And acetic acid which looks like this

而醋酸是酸，它是这样的

it makes vinegar sour

它让醋具有酸味

Alright, let's look back at our cylinders here

好，我们再来回头看这些柱形容器

This first set of cylinders contains the indicator bromothymol blue

第一组柱形容器中装的指示剂是溴百里酚蓝

Let's take a look at the spectrum

我们来看看光谱

Alright, so let's take a look at bromothymol blue

好，我们来看看溴百里酚蓝

the indicator in the first set of cylinders

这是第一组柱形容器中的指示剂

As you can see here, there's a scale of numbers. This is the pH scale

这里可以看到一些数字刻度，这些是pH值刻度