Putting Things Together
When we have different things and put them together we get different results - put together salt and water and you get salt water; put together sand and water and the the sand sinks to the bottom and the water to the top; put together baking soda and vinegar and you have a bubbly, frothy mess! Scientists use different terms to explain what is happening in each of these different circumstances: solutions, mixtures and chemical reactions. Let’s explore each of these.
Mixtures
A mixture is a combination of things - elements, molecules or compounds where the things being mixed do not react with one another - they stay seperate and can later be separated out. Bertie Botts Every Flavour Beans boxes contain a mixture of different flavors - just be careful to pick a good one!
A solution is a type of mixture where the things being mixed together end up evenly distributed. The molecules in a solution still don’t combine with each other and change into something new - that is what happens in a chemical reaction. The molecules in a solution can therefore still be, separated out, although it may take some effort. Above is a picture representation - both are mixtures, the one on the right has the molecules evenly distributed, and is a solution.
Solutes and Solvents
Here’s how a solution works: one substance, called the solute, usually a solid or gas, is what scientists called dissolved into another substance, called the solvent. Water is the most common solvent and we call such solutions aqueous solutions. Ocean water is an example of a solution of salt (the solute) dissolved into water (the solvent) - you can separate �them out by letting the water boil �or evaporate off and you will be �left with the salt!
What is Dissolving?
Dissolving is the process by which a solute breaks up into smaller pieces so that the molecules of the solvent can get in between and distribute themselves. To make our solution for our sugar quills we use water as the solvent and sugar as the solute. The sugar is more dense than our solvent, water, and their molecules are closer together. When you add sugar to water it usually just sinks to the bottom? How do we get them to move apart to let the water molecules in between without changing them?
Adding Heat
One way to dissolve a solute into a solvent is to use heat. Why does this work? Because when you add heat, you increase the motion of the molecules and they start to move away from each other. Moving the molecules away from each other in our solutes and solvents is exactly what we need to create space between them so that the other molecules can slip between. This ensures an even distribution.
More on Dissolving
All the talk of solutes and solvents can be a bit confusing. To clear it up I recommend watching the first video below. The second video is for those of you who want to delve a little deeper into the science.
Saturation
One characteristic of all solutions is their saturation. This has to do with how much solute you can add to a given solvent before the solvent can no longer dissolve the solute. Try saying that three times fast! An easier way to think about it is that all solutions are either:
Saturation Clarified
It still sounds a little complicated, especially because we are using the words “solute” and “solvent.” Let’s take a look at this video for clarification: