Hello all. Welcome to Teacher Night.
And this is the science of the chocolate chip cookie.
Here we have the ingredients for the first type of cookie we're going to make.
The thin and crispy cookie.
We have regular, all-purpose flour.
Salt.
Baking soda.
Vanilla.
Brown sugar.
White sugar.
One egg.
Some milk.
And, of course, butter.
And it wouldn't be a chocolate chip cookie without the chocolate chips.
Then, we're going to go to the chewy cookie.
Which has some of the same ingredients.
We've got bread flour.
We've got salt.
Baking soda.
We've got one egg plus the yolk of a second egg.
Some more whole milk.
Sugar.
Vanilla.
There's our chocolate chips.
And brown sugar.
In the back you're gonna notice parchment paper.
If you haven't discovered parchment paper yet, when you bake, you need to do that.
This stuff is magic.
And the butter for this is in the glass dish here, the Pyrex, because it needs to be melted.
So that is going to be one part of what we're doing.
Okay, first you need sift the flour and... baking soda and salt together.
Set that off to the side.
Take the cold butter, the white sugar and the brown sugar, and put them in the blender,
and let that thing do its magic and get it all mixed up.
After you're done doing that, then you add the other wet ingredients.
The vanilla, the milk, and the whole egg, and get that all mixed up nice and good.
When you get to the part where you're adding in the flour, do it slowly, a little bit at a time.
Because, if you don't, you're going to end up a with huge mess.
So, start slow. Speed it up.
Add 'em in a little bit.
And then, at the end, put in your chocolate chip cookies.
Put 'em on the trays.
So that they're ready to go.
These are the thin and crispy ones about to go into the oven.
Okay, so the thin and crispy cookies are complete.
The chewy cookies are all mixed up and ready to go in.
We'll discuss the differences between the two in a bit.
Okay, so here we are with the finished product.
This is your thin and crispy cookie.
It is quite thin.
It's got a nice crisp on it.
It is still a little warm, so it's kinda gooey in the middle.
And then we've got the chocolate chip cookie that's the chewy one.
This one's going to stay that way, even after it cools completely.
Now, they're a lot of things you can talk about when doing this lesson.
You can talk about the difference between physical and chemical change.
When you have the butter in the one that's solid and the other one is melted.
If the melted butter is allowed to re-solidify it'll be butter the way it was again.
And you have a mixture as well as a compound in here.
Because, you look at the chocolate chips, they're not the same distribution throughout all of them.
So that makes it a bit of a mixture.
But, when you take the baking soda, the proteins from the eggs,
the oils from the butter, and you put all of that together,
it makes the compound which is the cookie, which you could not take apart, even if you tried.
The chocolate chips, obviously, you could pick those out if you didn't want to.
But why would anyone do that?
That makes no sense.
So, typically when we do experiments, we like to only have one variable.
Well, when you're doing something with baking, sometimes you have several different variables.
We had different amounts of egg.
We had different types of sugar.
Different amounts of them.
The butter was melted in some.
It was solid in others.
So you've got an opportunity to talk about how
the scientific method is different depending on what you're doing.
Also, when we talk about observations in science, normally we're only talking about our sight.
Maybe the smell a little but.
You could hear some things with it.
The feel. The texture.
This is one of the few experiments where you can actually taste
and use all five senses to work on it.
And I'd like to give a shout-out to Alton Brown,
whose idea this came from, from his show Good Eats -
The Chocolate Chip Cookie Caper.
Anyway, try this with your students.
I find that it works as a good extra activity for those who want something challenging to do.
Something at home that their parents are willing to work with them on.
Thank you very much.
Have a good evening.