Posts Tagged ‘ Classic Science ’

Baking Powder Power

February 25, 2010

In my previous posts on how to teach science at breakfast we focused on how the concepts of atoms, density, diffusion, and the Law of Conservation can be found during the first meal of the day. We’ll return to a couple of these concepts throughout this post, but I think it’s time to look at something a little different. For example, in my last post I hinted at my recipe for pancakes:

“…a little flour, an egg, some milk, a small amount oil and sugar, and a few pinches of baking powder and salt…”

We talked a little about the science within the sugar and flour, but many questions were left behind. For example:

What exactly IS baking powder?

Well, baking powder is collection of different kinds of molecules (groups of atoms). Whatever brand of baking powder you have in your kitchen, they ALL contain the same combination of molecules:

Molecule #1 – A dried acid (possibly Cream of Tartar – which is known to us scientists as Tartaric Acid)

Molecule #2 – A base known as sodium bicarbonate (also known as Baking Soda)

Both baking soda AND baking powder can usually be found in your kitchen cabinet. But as you just learned, they are definitely not the same. Each product contains different molecules and have different properties. For example:

What does the acid in baking powder do?

To answer that question, you have to understand what happens when you mix together a base (like baking soda) with an acid (like Cream of Tartar.) When these two molecules are dry, they cannot react with each other very well.

However… If you dissolve these solids in a liquid, all these atoms REALLY start to move around!

You see, whenever you mix acids and bases together, their atoms start to break apart from each other and rearrange into new molecules! This is exactly what the Law of Conservation states – atoms cannot be created or destroyed, only rearranged.

When you mix a fluid like water with baking powder, the new molecules that are formed are in the form of a gas called carbon dioxide. These molecules form very quickly in your pancake batter.

I’d guess that most of us have attempted to make the famous “Volcano Eruption” either at home or school… Mix together a little vinegar (acetic acid) and baking soda and you get a fast-moving bubbly mess! This is the same reaction that is taking place within your pancake batter. The only difference is the type of acid that is being used.

Since we are on this topic, I’d like to apologize to my mother once again for all of the “kitchen experiments” in my childhood that taught me how messy science can be. Love you Mom! Feel free to send me the cleaning bill. I think I can afford it now!

So gas is being produced when I mix together a pancake batter?

You bet it is! In fact, it is a good idea to mix together your ingredients within the pancake batter (gently), and let it rest for a few minutes before you start to cook.

But I’m hungry and the batter is ready! Why should I wait???

By waiting a few minutes, the acids and bases within the baking powder start to dissolve within the batter and react with each other. This produces millions of tiny bubbles (carbon dioxide) into your batter which will help your pancakes be nice and fluffy!

So what else can be done to keep my pancake from looking and feeling like a hockey puck?

Well, the oil you add to your batter keeps your pancake from getting too firm AND all that sugar isn’t only to satisfy your sweet tooth. Sugar has a good way of absorbing liquids which keeps your batter nice and moist.

There’s another trick to keeping your pancake fluffy. I mentioned it earlier in the post when I suggested that you GENTLY mix together your batter. Why shouldn’t you put your pancake batter in a blender for awhile? The answer to THAT question is hidden inside the chemistry of flour which we will be looking at next week. Stay tuned…

Find out more about scientific concepts for your family within the Classic Science Curriculum

Be certain to check back every Thursday or subscribe to the Blog of Mr.Q for weekly updates.

How To Teach Science During Breakfast… With Pancakes!

February 18, 2010

By Scott (aka - Mr.Q)

This week, we will be looking at one of the heavyweights of breakfast menus. All you have to do is mention its name and children will come running. In fact, as I look back into my childhood, this breakfast meal was one of the first foods I was ever allowed to cook. That’s right, we are talking about pancakes!

It is so easy to put together a little flour, an egg, some milk, a small amount oil and sugar, and a few pinches of baking powder and salt (with a little bit of vanilla, cinnamon, and nutmeg for some flavor.) I was always amazed that so few ingredients mixed together would bring out such an amazing meal.

But what is going on inside that marvelous mixture?

That is what we are exploring today. Let’s review our four main concepts of science before we move on:

The atoms within your pancake batter will not sit still!

It may be true that atoms cannot be created or destroyed, but they are definitely being moved around within that pancake batter. By far, the most important molecule (a group of atoms joined together) within that mixture is known as starch and it makes up most of the flour within your ingredients.

If you could shrink down to the size of the comma on this screen, you would see exactly that starch looks very much like a chain with thousands of links bound together. Each link of this chain would actually be a sugar molecule.

That’s right! Starch is really just a huge chain of sugars bound together and it makes up more than half of that batter. And it doesn’t sit still very long after you add some milk…

Diffusion, Density, and Dairy

Remember! Most of that liquid batter you just mixed together is made up of long chains of sugar. Once you add milk to that powdery mixture, all that starch begins to absorb the milk. This diffusion of milk into the starch speeds up when you start heating it up on the stove.

Why?

When atoms absorb heat energy from the stove, they start moving around a lot more. Since the atoms that make up the liquid milk are already moving around quite easily already, the additional heat energy allows them to move even faster. All this extra movement causes these atoms to slam into the starch molecules. So while you are cooking your pancake, the starch absorbs more and more liquid. Another way to say all of this is…

The milk diffuses into the starch molecules and causes the starch to become more dense.

LIQUID Batter + Heat = SOLID Pancake… Huh?!?

You may think that something strange happened to those atoms in your liquid batter as it turned into a solid pancake before your eyes. And it did!

Think about it… Liquids are not supposed to turn into solids as you add heat!

But the Law of Conservation states that atoms cannot be created or destroyed, only moved around. So this means that something else is going on. Hmmm….

The answer lies within the starch molecules of the batter. As the starch swells, some of their sugar molecules break off and flow away in the mixture. These sugary molecules swimming around in your batter help to make the batter a little stickier. It is this “stickiness” that gives your pancake that spongy feel after it is cooked because it holds all of those starch molecules together.

Now some of the water molecules within your milk do tend to escape as steam while you cook your pancake. But they do not disappear! They absorb the heat energy from your skillet, break away from the batter, and spread out into the air. But they are definitely not destroyed!

We could spend weeks learning how atoms, density, diffusion, and the Law of Conservation can be found within our breakfast. But I’m getting hungry for something else. Besides, there are so many other cool things to study in the kitchen. For example…

Where do all those little bubbles come from while the pancake batter is cooking?

Come back next week and find out when we look at The Chemical Reactions in Our Food!

Be certain to check out all of the posts in this series:

How to Teach Science During Breakfast… With Bacon

How to Teach Science During Breakfast… With Coffee

How to Teach Science During Breakfast… Soggy Cereal Science

How To Teach Science During Breakfast… Soggy Cereal Science

February 11, 2010

By Scott (aka - Mr.Q)

So far, we have learned how cooking bacon and brewing coffee can be used to teach science during breakfast. Now it’s time to turn our attention towards another common early morning meal – cereal.

Before we do, let’s review the four basic concepts that can be used to teach science:

Now go grab a box of Cap’n Crunch or Cheerios and let’s get to work!

What’s going on with the atoms in your cereal?

First, you should know by now that everything within a bowl of cereal is made up of atoms. The bowl, spoon, milk, and cereal itself are all made up of atoms! Within each solid piece of cereal you may find billions of atoms, all vibrating against each other. That’s right! All atoms within a solid, even the ones that bind together to make Corn Flakes, are moving a little bit.

Of course, the atoms that are bound together to make up the liquid milk are moving around a lot faster. That is what happens in every liquid!

What does density have to do with all of this?

When you pour your milk over a bowl of cereal, does the cereal sink or float? It probably floats! But why?

Well, the amount of atoms that make up the cereal are not equal to the number of atoms within the milk inside the bowl. This means that the density of the cereal is less than the density of the milk. When you mix two objects together of different densities, the one with the lower density will float!

Quick!!! Eat your cereal before it gets soggy!

You can thank diffusion for the unfortunate (and soggy) end for those last few pieces of cereal in your bowl. This squishy transformation takes place when the huge amount of fast-moving atoms inside the milk slams through the slow-moving atoms within the cereal. Another way to say this is this: The atoms within the milk diffuse into the collection of atoms within the cereal.

And with all this milk being absorbed, it quickly increases the density of the cereal (so much so that it causes the cereal to sink to the bottom of the bowl as a spongy pile of goo.)

Now if you choose a more sugary cereal you may have a few more minutes until your bowl becomes filled with a dissolved gummy slime. Why? Well, it takes a little longer for the milk to diffuse into the cereal because it has to dissolve the sugary coating first.

That’s why your Cap’n Crunch will float on top of your milk a little longer than your Cheerios!

“Hey?!? What happened to my cereal?!?”

Remember the Law of Conservation – Atoms cannot be created or destroyed, only changed.

All those soggy chunks of cereal may sink to the bottom of the bowl, but they cannot disappear after soaking for awhile. They might break apart and change shape, but your soggy Corn Flakes will never lose a single atom!

Atoms, Density, Diffusion, and the Law of Conservation…

…all at the breakfast table!

Find out more about scientific concepts within the Classic Science Curriculum

Be certain to check back every Thursday or subscribe to the Blog of Mr.Q

How to Teach Science During Breakfast: Soggy Cereal Science