Process and Alterations:
Use the same lesson as Part 1 but this is with some expansions and alterations:
We will be involving a little bit of physics, math, and chemistry as well as learning the colors. So you can follow the steps in Part 1 similarly to get your student to experiment and discover how color works. Ideally you want to have them create a color wheel or some organized chart to display their findings before even knowing a color wheel exists. But here are some more alterations you can make to the lesson:
THE BATTER – MATH
Your student that is in their middle school years might be experimenting with fractions and decimals. If they are, I can’t think of a better visual aid than measuring cups to show sizes and amounts. This is also a great way to learn that 1/2 of a 1/2 is a 1/4. Because you can see it!
You could do a lot of creative math experiments or reinforcement here. Some really good ones would be:
1/2 the recipe to make a smaller batch
2x the recipe to make a bigger batch or (2.5x the batch to make it really challenging)
Conversion of tsp to Tbl to C. How many?
They can do the conversions however they feel the most comfortable under your watch. Ask questions only and allow them to make mistakes (in dry ingredients. Stop them before adding the wet ingredients if its just going to foul up the entire batch).
THE BATTER – CHEMISTRY (and vocab, spelling, what have you)
I think the best chemistry lessons baking can offer is pH testing and leavening. This is because they work hand in hand. Here is some background:
We like to eat things that are slightly to extremely acidic. Most foods are acidic on the pH scale (1-7, with 7 being neutral). If we eat something with an alkaline pH (7-14), it tastes like soap (or baking soda). So it could be fun to get some litmus strips and dip them into separate ingredients (wet baking soda would be awesome to test) and/or the batter and record the pH levels of the food. These strips are inexpensive and can be used in a multitude of ways…even on your own saliva to give you a hint on your body’s acidity/alkalinity. (which I am no MD but I pretty sure optimal health is slightly alkaline. Metabolic acidosis is bad news especially in women due to the increased loss of calcium)
Leave the ingredients out for pH testing and have the student record their findings. They can even try to make an educated guess on the final pH level of the batter after all the ingredients are mixed and ready for the oven…THEN TEST IT!
Most leavening we use in baking is either chemical or organic. The organic kind is usually yeast where the little critters convert sugar into energy and release carbon dioxide. Carbon dioxide is heavy enough to be trapped by dough/batters. This is what causes the cake to rise and when you cut into it you will notice a tiny round pockets made by the carbon dioxide.
You could introduce the idea of using the chemical name Sodium Bicarbonate. Then look on your label of Baking Powder (Double Acting please if making by scratch) or your cake mix box. You will notice something. It’s in there! Your student will notice that Sodium Bicarbonate (after the pH test is done on the wet stuff) is alkaline…very much so.
By itself sodium bicarbonate does nothing. Have them add a little vinegar (an acid) to the powder and have them write down their observation. A gas is released: Carbon Dioxide. The mixture of acid with the alkaline causes a chemical reaction and carbon dioxide is released as a result. This is the gas we need for the leavening and will make the cake rise. BUT you don’t want to put vinegar in your cupcakes…eeeeewwww. So you need other acidic ingredients to react with it.
Like I’ve said, most of the food ingredients are acidic and we want an acidic taste. So we have plenty of acid to make the reaction in the baking soda from the food. It doesn’t take a whole lot to make the reaction. That is why you will always see 1/8-1/4 of tsp of NaHCO3 (baking soda) or a small amount of baking powder. So a little sodium bicarbonate will bring down a little bit of our acidic taste but the batter should be acidic enough to allow it to taste good.
BAKING TIP: This is why you wait to add the wet ingredients until right before you want to put them in the oven. Otherwise it will sit on the counter loosing your precious leavening power. The wet ingredients allow the dry baking soda and other dry food stuffs to mix and react.
Double Acting Baking Powder
Like I said before, your student will notice sodium bicarbonate as an ingredient in baking powder. They will also notice some other ingredients. But after they experiment with the baking soda and vinegar and get the acid/alkaline concept down. Here is what they should do:
1. Have them mix some baking POWDER with some water. Have them write down their observation
– They should have noticed a chemical reaction and gas release
2. Have them hypothesize what happened.
What has to happen to allow this to happen? Does the water provide the acid the baking POWDER needs? (no it doesn’t) Then what caused it?
3. Their conclusion will hopefully be along the lines that one of the other ingredients in the baking POWDER is acidic to react with the baking SODA but you need the water to allow them to mix and react with each other.
4. This allows us to have a good rise without using the acidity of the food.
Other ingredients of Double Acting Baking Powder:
The Sodium Aluminum Sulfate reacts with the baking soda to cause immediate CO2 (carbone dioxide) release. So Sodium Aluminum Sulfate is acidic but needs water to interact with the baking soda.
Monocalcium Phospate is also acidic but produces more CO2 when introduced to heat. So this is the 2nd (or double) leavening action we get after we put the cupcakes into the oven.
Have your kiddos experiment, theorize, and conclude. Let them really investigate and understand what is going on. Let them ask questions and be ready to ask them more back to lead their thinking if they need help.
COOL STUFF (well, ok, its hot)
Here is a cool video on chemical leavening agents and their purpose in baking:
The leavening part is at the 17:27 mark
THE FROSTING – COLOR
Along with learning about Primary and Secondary colors in the fashion of Part 1 , your student should learn the subtle difference of tertiary colors
These are slight shade variations between secondary colors. So a blue-green hue would be a tertiary color between blue and green while a yellow green hue would be between yellow and green.
Tertiary colors are created when you mix 1 primary and secondary color or 2 secondary colors together.
Have them create a color wheel with 3 levels and have them organize it in their own best way that makes sense to them. Here is an example: