Hey! Who took the labels off these three glasses? They were there so I would know which of these liquids to use to clean my shirts, which one to use to clean the rust off this shovel, and which one to drink! Now they all look the same! Why do I not just taste them, you ask? Well, two of them are poisonous while the last one is just water. I do not like my chances. Each liquid could be one of the three things. How are we going to figure out which one is which?
Why do all of the glasses look the same? I poured two solids into the water to make them weaker and easier to spread around. They dissolved! They disappeared! A solution
is a liquid in which something is spread out, or dissolved, so that you cannot see it anymore. The solids I put into the liquids spread out until they didn't look like solids anymore. They just look like three glasses of water. The three could not be more different, though . . .
One of the three glasses is something that can make my white shirts even whiter. A base
is something that makes a lot of hydroxide ions when it's in water and is high on the pH scale. Bases are bitter and the stronger ones act like soap. Bases are great at breaking up fats and grease. If I drink the base, I will die. If I try to use it to take off the rust on my shovel, it would make it worse!
Ammonia and bleach, good for cleaning, bad for drinking.
One of the glasses in front of you has something that can take the rust off my shovel. An acid
is something that makes a lot of hydrogen ions when it's in water and is low on the pH scale. They taste sour and you can find some of them in oranges and lemons. Of course, this one is a lot stronger than that. It can take the rust right off the shovel because they react easily with metals. If I tried to wash my shirts with it, it would eat right through them. If I drank it, it would eat through me!
When life gives you lemons, make lemonade.
One of the glasses in front of you is safe for drinking. We can make something neutral by mixing an acid and a base together to make water again. Neutral
means that something is a 7 on the pH scale and that it is not an acid or a base. Pure water is neutral. This is the safe glass. This is water that you can drink. It's great for thirsty people. Since it is right in the middle, it does not react with a lot of different things like the other two glasses will.
I'm not sure if this glass is half full or half empty.
Now it's time to figure out which is which. Lucky for me, I do not need to guess and maybe get more rust on my shovel, put holes in my shirt, or die. By just sticking this little piece of litmus paper into the liquids, we can see what color it becomes, and that tells us everything we need to know. The first one is a strong acid that can help me clean rust off a shovel. The second one is a strong base that can help me make my shirts whiter. The third one is water that I can drink. By adding each of these to a different solution we could see how they reacted and know what they were. What am I going to do with white shirts, a shovel, and a glass of water? Dig a hole, get dirty and sweat and then wash my shirts while I drink a cold glass of water. Of course.References:
Ducksters. "Acids and Bases" Ducksters, 2011. <http://www.ducksters.com/science/acids_and_bases.php
Chem4Kids. "Acids and Bases Are Everywhere" Chem4Kids, 2012. <http://www.chem4kids.com/files/react_acidbase.html