Lesson: Understanding pH
In this lesson: Understanding pH we will be learning to understand the 0-14 acid to base scale. We will also go about creating our own test strips using Universal Indicator and special paper. Then we will be testing several substances around the farm.
Acids, Bases, and Alkali
So, do we know what an acid is? First we need to understand atoms and ions as well as chemistry. Once we know that, an acid is any material that gives or takes an ion.
When we talk about ACID we think of melting things with a liquid. There is a strong acid in your stomach right now! It’s in your stomach and acids are how we tear food apart into glucose, fats, and minerals.
The stomach isn’t the only place in the body where we will find acids! Acids make all parts of life possible. They give energy to systems and make things happen in our cells right down to the formation of DNA (DeoxyNucleic Acid).
Now, we need to know what a base is. A base is anything that counteracts an acid! Bases have some peculiar aspects too.
Most, but not all bases are metals or metal hybrids and salts. This is because the bases have peculiar aspects. Acids are almost always mixtures, while bases tend to be simpler.
Some bases are slippery or soapy feeling. Some bases can actually burn you. The burning bases are called alkali.
The alkali bases are important in energy production as they can store and release energy as well. That’s how batteries work, by interacting with acids and bases within the battery, the electrons get released to power devices.
Just like the acids, our body is FILLED with bases as well. Even good old DNA has bases in it. Remember, bases counteract the energy of acids.
When They Meet…
Most people know that when you mix baking soda and vinegar you will get a reaction. But do we know why? It’s the acid (acetic acid) reacting to the base (sodium bicarbonate). When they react, they release energy in the form of heat and O2 and CO2 molecules.
Remember, everything comes down to energy. The chemistry of acids and bases is really all about reactions. That is why they are so central to chemistry.
Universal Indicator and Litmus Paper
We can use the pH of acids and bases to understand what they are going to do on a farm. To do this we need to make what is called a pH strip. It is a simple thing, reactive paper and a complex chemical solution that changes color when in contact with specific acidic or base compounds.