In past entries, we have explored the concepts of starch, flour, gas production with leavening agents and how all of this affects the baking of dough.  Last week, we even looked at how cookies spread out during baking and firm up as they cool.  The “hidden mysteries” that exist within the kitchen should not be too great of a mystery at all!

(That is, if you know what you are looking for.)

It all comes down to some basic concepts that can be hard to witness in real life:

If you have been paying attention, you should have a pretty good idea how a semi-solid goo like batter can turn into a firm cake in the oven:

• The batter rises as gas bubbles within the mixture gets larger in the oven.
• Starch from the flour begin to swell as water DIFFUSES into its structure.
• Protein within the egg stretches out to forms a firm “web” within the cake and hardens as it cools.

All of these changes follows the LAW OF CONSERVATION as ATOMS within the heated cake batter are not created or destroyed, just rearranged into delicious ways.

However, if I have learned ANYTHING by studying science is that there are ALWAYS hidden factors that can easily affect all of these rearranging ATOMS.  And there is a lot of rearranging going on inside that sticky, gooey fluid within your mixing bowl – before, during, AND after the baking is done.

One of these “hidden” factors is easily overlooked by most household cooks (unless they live in areas like Denver, Colorado.)

AIR PRESSURE

You feel the effects of a change in air pressure every time you fly in a plane, travel up or down a mountain, or submerge yourself under the water.

Air pressure is defined as “the weight of the air above a certain point on the Earth.”  So if you think about it, a person like me who lives in Missouri has much more air pressure pushing down on my body than my friends who live in Denver, Colorado.  The air pressure in Denver is not nearly as great because the entire Denver area is over 10 times HIGHER in the air as compared to Missouri!

SO WHAT DOES AIR PRESSURE HAVE TO DO WITH MY CAKE?

Well, the heat you add to your cake batter is needed in order to speed up ATOMS, create gas bubbles, melt sugar, and stretch out protein into long strands to make the texture of your cake.  Right?

And areas with higher air pressure, like Missouri, have a greater weight of air pushing down on the cake batter as it is cooking.  Therefore, the greater the pressure, the more energy it takes for liquid molecules (from the egg and melted butter or fat) to escape from the batter and become a gas.  Because of this increased pressure, it takes more energy (crank up the oven!) to bake your cake at lower elevations.

Do not confuse this increased or decreased weight with the DENSITY of air over these two cities.  Remember, DENSITY is the amount of ATOMS that can be found in a certain area.  For example, the amount of air molecules in a one-mile area above Denver AND Missouri may be the same.  However, there is MORE air between Missouri and outer space than there is above Denver. All of these extra air molecules give Missouri a greater air pressure compared to Denver.

Is that as clear as mud?  Or perhaps cake batter?

Most recipes we read are for areas of high air pressure because most of us in the United States all live at lower elevations.  However, if you followed a Missouri recipe to bake a cake in Denver, many bad things would probably happen:

• First, your batter will lose its moisture much faster because there’s not as much air pressure pushing it down into the batter.
• Second, the bubbles of gas within your batter will increase much faster because there is not as much air pressure pushing in on them and keeping them small.
• Third, the protein and starch firm up much slowly because the batter temperature does not get as hot.

Therefore, your light and fluffy cake in Missouri will probably end up dry, dense, and flat.  Yuck!

SO HOW DO YOU FIX THIS PROBLEM?

• First of all, you can always add a little more liquid to the recipe.  Since heat will DIFFUSE faster through a liquid at low air pressures, the increased liquid will allow for evaporation to take place for a longer time.
• You can slow down the expanding bubbles of gas by reducing the amount of leavening agent in your recipe.  This reduction will keep plenty of gas bubbles in your cake AND keep it from becoming too DENSE during the baking.
• And third, you can speed up the firming of protein and starch by reducing some of the other ingredients, like sugar and fat, from the recipe.  These ingredients tend to get in the way of protein and starch during their firming process.  Reducing them from the recipe will allow your cake to firm up much faster!

Learn more about chemistry concepts (and many more) in the Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!

Every family has their own favorite desserts.  Some families enjoy the creamy coldness of ice cream, some are happy with a fresh bowl of fruit like strawberries, and other families come from a deep tradition of baking.  This week, we pay homage to all those families who pull out their mixing bowls and crank up the oven to make the ever popular…

COOKIE

As you know, cookies come in a variety of shapes, styles, and flavors.  However, most cookies share the same common ingredients:

I could spend weeks explaining how the four basic concepts of science can be found within these basic ingredients.  However, I was always taught that “Less is More” so let’s look at how these four concepts are found in the BAKING of our cookies:

For the record, I’m going to be discussing the baking of drop cookies (like chocolate chip or oatmeal cookies.)  It’s not that I have a personal favorite (oatmeal cookies) and it is not my wish to offend any bar- or cut-out cookie fans, it’s just a random decision (yeah right) I have made for this post (because oatmeal cookies are the best.)

THE INGREDIENTS ARE ONLY THE FIRST STEP

The proportion of ingredients helps to create the crumbly, crisp, or chewy texture of a cookie.  For example, shortbread cookies are made up of much more flour than water which helps to provide a crumbly texture.  However, if your ingredients consist of more water than flour, you can end up with a crispier cookie, like a wafer.  Drop cookies are somewhere in the middle.  They have about half as much water in them as flour.

Where does the water come from?

Well, I’ve never seen a recipe for oatmeal cookies that require water as an ingredient.  However, there is plenty of water within the eggs and fat (butter) of most drop cookies.

HERE COMES THE SCIENCE STUFF…

Flour and water help create the variety of cookies we know and love, but it is SUGAR that gives a cookie most of its structure and texture.  Drop cookies tend to contain equal amount of flour AND sugar.

The high DENSITY of sugar molecules within the soft cookie dough of drop cookies goes through several changes as you heat them up in the oven and cool them off on the counter.

Remember – A molecule is a group of ATOMS which are bonded together.  In the case of sugar, you are looking at a large number of Carbon, Hydrogen, and Oxygen ATOMS.

Sugar molecules tend to stick together very well.  Thousands (if not millions) of sugar molecules are bound together in every single visible grain of sugar!  When heat energy is added to this collection of molecules, they tend to shake or vibrate away from each other.  You have seen this happen when ice melts…  The molecules of water absorb heat from the environment and moves away from each other to form liquid water.  Well…

SUGAR DOES THE SAME THING!

THE SECRET INGREDIENT IS DIFFUSION

As the solid sugar molecules break apart (DISSOLVE) in the presence of heat, the molecules tend to move away from each other by the process of DIFFUSION.  And the cool thing is that you can witness this diffusion every time you bake drop cookies.  Your little ball of soft dough spreads out all over the cookie sheet.

How does this happen?

The liquefied sugar, combined with the water in the eggs and butter, cause the soft dough to spread out onto your cookie pan during baking.  That’s right!  The dough DIFFUSES throughout the cookie sheet.

What happens after you turn off the heat?

This is an easy one to answer.  Let’s return to our story about water…  What happens to liquid water when you take away all of its heat energy (think of a glass of water inside a freezer.)  You guessed it!  The liquid water will freeze into a solid.

This is what happens to liquefied sugar as well!  The sugar molecules change back from a liquid into a solid and give your drop cookie a firmer, cake-like texture.

A SERIES OF UNFORTUNATE EVENTS…

Unfortunately, the average life of a homemade cookie is very short.  Even if you store them in an airtight container, they will eventually show their age.  This follows the LAW OF CONSERVATION which states that ATOMS cannot be created or destroyed, only rearranged.

During the demise of your oatmeal cookies, no ATOMS are altered in any way.  It is the process of DIFFUSION that is responsible for their untimely “death.”  Let me explain:

It is true that the texture of drop cookies changes rapidly over the course of a few days.  These soft and chewy cookies tend to DIFFUSE their water into the environment rather easily.  Without this water, your cake-like oatmeal cookies tends to resemble a hockey puck.  Yuck…

So if  you have learned anything from all of this it should be….    EAT THOSE COOKIES AS FAST AS YOU CAN!

Learn more about chemistry concepts (and many more) in the  Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!

Last week, we took a brief look at the science of ice cream.  And why should we limit ourselves to this creamy dessert when we can add so many different toppings?  I know that everyone has their own favorites – peanuts, chocolate, sprinkles, anchovies, etc.

By far, my favorite topping on ice cream HAS to be an all-time favorite…

THE STRAWBERRY

Strawberries were a favorite dessert in my family.  I remember my grandmother serving me a bowl of this amazing fruit and it was always found in bowl of its own sweet juices.  I never even questioned HOW she could create all that juice from just a handful of berries.

I figured out this “secret” after watching her prepare this treat…

SHE SPRINKLED SUGAR OVER THE FRESHLY CUT BERRIES!

There is a lot of science behind this seemingly simple recipe and ALL of it follows the four main concepts of science very well:

We already know that all of that juice that rests at the bottom of your sugared berries doesn’t come from nowhere, right?  It HAS to follow the LAW OF CONSERVATION which states that ATOMS cannot be created or destroyed, only rearranged.

THIS MEANS THE JUICE MUST COME FROM INSIDE THE STRAWBERRIES!

The movement of juice from inside the berry into the bowl is due to DIFFUSION.  You see, sugar begins to dissolve in the small amounts of water found on the surface of the berries.

Scientists call the molecules that dissolve in a fluid a SOLUTE.  The fluid itself is called a SOLVENT.  And, when a solute is dissolved into a solvent, a SOLUTION is formed.

Okay, back to the story…

Scientists would say that a sugar solution is formed on the surface of the berry.  This is very important to the DIFFUSION of juices.

The entire purpose of DIFFUSION is to spread out a group of ATOMS evenly.  But if you have more molecules of water INSIDE the strawberry than on its surface, the water molecules start to DIFFUSE through its surface and towards the OUTSIDE of the strawberry.

Scientists call this process OSMOSIS (“oz-moh-sis”) which is the movement of ATOMS through a membrane in which an equal DENSITY of solute are eventually found on BOTH sides.

The result of this DIFFUSION is a very sweet juice in the bottom of the bowl.  The longer you let the strawberries sit in the sugar solution, the more water will move into the bowl, and the more shriveled up the berries will look.

My grandmother may have never known about the four basic concepts of science, but she certainly knew how to put together an amazing dessert!  Thanks Grandma!

Learn more about chemistry concepts (and many more) in the Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!

With the hot weather coming our way, I would guess that many of you are going to need some refreshing desserts to cool you down.  This week, not only are you going to learn the science behind ice cream, you are going to learn how to MAKE ice cream!  Let’s get to the good part first…

Here’s what you need:

Here’s what you do:

Pour all of the ingredients except for the ice and salt into the quart-sized baggie. Seal it up and mix well!

Place the ice and rock salt into the gallon-sized baggie.

Now place the sealed baggie with your cream mixture into the larger baggie and seal it up.

Shake the bag from side to side for about 10 minutes. You may want to cover the bag in a towel if your hands get too cold.

Open the gallon bag to remove the smaller baggie when the blended mixture has solidified into ice cream.

What’s going on?

The four main concepts of science are easy to observe while making ice cream:

The ATOMS that are found within the liquid milk have a lot of energy as they move around freely and bounce into each other and the side of the baggie.  It is very easy to DIFFUSE energy from a warmer liquid (like milk) into the ice within the baggie.  Remember, DIFFUSION is the movement of atoms (or energy) from high concentrations into low concentrations.

Ice has to absorb energy in order to melt. When you use ice to cool the ingredients for ice cream, the energy is absorbed from the ingredients and from the outside environment (like your hands!)

When you add salt to the ice, it lowers the freezing point of the ice, so even more energy has to be absorbed from the environment in order for the ice to melt. This makes the ice colder than it was when you put it in the baggie!

This super cooled ice DIFFUSES more and more heat energy from the liquid milk.  As the ATOMS within the milk lose energy, they slow down, line up (like soldiers in formation), and form what is known as crystals!

Many people may believe that the creation of this frozen dessert is nothing short of magic.  Naturally, we already know that you have not created any new ATOMS with all that mixing of the baggie.  The creation of ice cream follows the LAW OF CONSERVATION which states that ATOMS cannot be created or destroyed, only rearranged.

And you rearranged a lot of ATOMS with all that shaking!

The real question is about the DENSITY of the newly created ice cream.  If you stopped shaking your mixture too early, you probably noticed that you had a pretty thick fluid that was only partially frozen.  If that was the case, your “ice cream” was really just frozen water mixed with the proteins and fat (inside the milk) and the sugar you added to the baggie.

If, however, you mixed your creamy dessert very well by shaking it around a lot you may have received a much less DENSE ice cream.  But how?

As you shook your baggie, you mixed in air bubbles within the freezing ice cream.  These bubbles get in the way of ice crystals as they begin to freeze together.  The result is a fluffier, less DENSE ice cream as the solid ice crystals get spread out a greater distance!

You want much fewer ATOMS inside a teaspoon of ice cream as compared to a teaspoon of liquid milk…  SO DON’T GO EASY ON THAT BAGGIE!  SHAKE IT UP!

Learn more about chemistry concepts (and many more) in the  Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!

Okay, I saved the best for last.  We are going to check out the “granddaddy” of all spicy foods. No other veggie can brag about such remarkably strong sensations as the fruit-bearing shrubs that are native to South America.

Grab a glass of milk and some tissues because it is time to dig into the…

CHILE PEPPER

There is a lot of science to be found within the chile pepper, and we are going to look at a few of these facts.  Fortunately, a solid understanding of the four basic concepts of science will help us out considerably:

BRING ON THE ATOMS

In the past three weeks, we learned that onions, garlic, and mustards store different kinds of molecules (groups of ATOMS) within their cells in different areas.  When we chop up these veggies, these molecules are allowed to come into contact with each other.  When this happens, these molecules rearrange their ATOMS into those delicious spicy-flavored chemicals.  Of course, all of this follows the LAW OF CONSERVATION as no ATOMS are created or destroyed throughout this movement.  However…

NO ATOMS REARRANGE TO PROVIDE THE SPICY CHEMICALS INSIDE CHILE PEPPERS!

You don’t need to wait for any rearranging of ATOMS within chile peppers to cause that amazing sensation.  Chili peppers make a special molecule known as capsaicin (“kap-say-sin”) which causes that feeling of heat in your body.

Chile peppers are mostly hollow on the inside and have a light-colored tissue which hangs below its stem.  Attached to this tissue (called the placenta) you will find the seeds of the pepper.  For years, people believed that the spicy capsaicin molecules were located within the seeds of a chile pepper, but this is not true!

IT IS THE PLACENTA THAT PRODUCES NEARLY ALL OF THE CAPSAICIN WITHIN CHILE PEPPERS!

Naturally, whenever you cut open a chile pepper you will cut through the placenta.  This will cause the capsaicin to DIFFUSE all over the seeds and tissues of the pepper (and your fingers too!)

You REALLY want to be careful not to touch your eyes after chopping up a chile pepper!

NOT ALL CHILI’S ARE THE SAME!

There are many different kinds of chile peppers in the world and all of them contain a different DENSITY of capsaicin.  The greater the DENSITY of capsaicin – the spicier the pepper.

For example, many people can eat the popular Jalapeno pepper by the handful!  Is this pepper hot?  Oh yeah!  But fewer people would ever TRY to eat a Cayenne pepper.  Cayenne peppers have THREE TO FIVE TIMES the amount of capsaicin within its placenta!

PUTTING OUT THE FIRE

Inside your mouth you have little sensors (like the ones that are in your car or computer) that can tell you if anything dangerous is going on.  Whenever you bite into a chile pepper, your saliva does an excellent job at DIFFUSING the capsaicin throughout your mouth and onto these sensors.

When this connection is made, the sensor sends a message to your brain that there is a HUGE amount of heat within your mouth.

Even though capsaicin DOES increase the temperature of your mouth a tiny bit, your brain may believe your mouth is on FIRE!

Naturally, the best way to put out the “fire” that is raging in your mouth is to remove the capsaicin.  But how can you do that?

DRINK MILK

There is a molecule in milk that sticks very well to capsaicin and will actually pull it away from the sensors in your mouth!  Neat trick, huh?  The coldness of the milk doesn’t hurt, either. If you don’t have any milk around, try some sour cream, yogurt, or ice cream. All of them have the same molecule.

Another way to cool the fire is to drink a sugar water solution (like Kool-Aid) as the sugar tends to reduce the capsaicin’s effect on your tongue.  Jalapeños and Kook-Aid?  I know it sounds a little strange, but it works!

We’ve spent a lot of time focusing on foods we typically find at the dinner table.  I think it’s time we start looking at our sweet tooth!  Next week we begin the series, “How To Teach Science With Desserts”

Learn more about chemistry concepts (and many more) in the  Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!