When I was only 5 years old, I remember watching a cooking show on television. The chef was
making this delicious looking cream sauce, and at the end he added several pats of butter. “Butter makes
everything better,” he said, as his concoction blended together perfectly. Sometime later I sat down at the table with my mom, and a cup of hot apple cider...and I remembered the chef’s assertion about butter. I can’t quite remember the face my mother made as I attempted to stir butter into my hot cider, but I do remember the result—greasy, yellow orbs floating menacingly in the pale brown liquid. Apparently, butter doesn’t make EVERYTHING better!
So why could the chef make a perfect sauce with butter, while my apple cider wound up a disaster?
The difference is caused by solubility.
making this delicious looking cream sauce, and at the end he added several pats of butter. “Butter makes
everything better,” he said, as his concoction blended together perfectly. Sometime later I sat down at the table with my mom, and a cup of hot apple cider...and I remembered the chef’s assertion about butter. I can’t quite remember the face my mother made as I attempted to stir butter into my hot cider, but I do remember the result—greasy, yellow orbs floating menacingly in the pale brown liquid. Apparently, butter doesn’t make EVERYTHING better!
So why could the chef make a perfect sauce with butter, while my apple cider wound up a disaster?
The difference is caused by solubility.
Solubility is the ability of one material to become fully dissolved in another, usually liquid, material. When one material is soluble in another, the two materials will blend together such that their individual molecules (their smallest building blocks) will be evenly blended together. If one material is not soluble in another, this material will remain in globs, and never blend evenly within the other material. For an example, let’s look at the butter again. When the chef made his cream sauce, he put the butter into a mixture of heavy cream and other fats, in which the butter is soluble. This is why the butter melted perfectly into the sauce. I had put the butter into apple cider, a drink made mostly of water, in which butter is not soluble, causing globs of
butter to simply float around in the cider without dissolving.
butter to simply float around in the cider without dissolving.
So why should butter be soluble in fatty heavy cream, but not in watery apple cider? The simplest explanation for this is that like tends to dissolve like—that is, fats will dissolve in other fats, but not in water. Because of this, the fats in butter will blend well with vegetable oil, which is also a fat, but not in water. Likewise, things that will dissolve in water—such as juice or coffee, which are made mostly of water—will not blend well with fats like butter or oil.
There is also a more complex explanation for this, which is polarity versus non-polarity. To understand what makes a molecule polar or non-polar, we have to look at what happens when the atoms (the most basic building blocks) that make this molecule bond with each other.
There is also a more complex explanation for this, which is polarity versus non-polarity. To understand what makes a molecule polar or non-polar, we have to look at what happens when the atoms (the most basic building blocks) that make this molecule bond with each other.
When two or more atoms come together to make a molecule, like hydrogen and oxygen bonding to form water, they share their electrons—the extremely small negatively charged particles that make up the outer cloud of the atom. These atoms may share their electrons equally, but sometimes one atom winds up pulling the electrons closer than the other. This unequal sharing is what happens with water: the oxygen molecule is more attractive to the electrons, and therefore the electrons want to be closer to the oxygen when it bonds with hydrogen. Because the electrons are closer to the oxygen, it has a slight negative charge, while the hydrogen has a slight positive charge. This slight negative charge to one end of the molecule, and slight positive charge to the other end is called polarity. Because of this polarity, the water molecule is very good at dissolving other molecules that are polar or carry an electric charge, like sugars or salts.
On the other hand we have non-polarity. This is what happens when the atoms of a bond share electrons equally, so no one atom holds the electrons closer than any other atom. As an example, let’s look at oil. Oil is made up of fats, or fatty acids, which are long chains of carbon and hydrogen atoms bonded to each
other. All the carbon atoms in this chain have the same attraction for the electrons, and so all share them equally. As a result, no one atom has extra charge, and the molecule is non-polar. Because of this non-polarity, these molecules will dissolve other non-polar molecules, like the ones found in butter. On the other hand, these molecules will not blend with polar molecules like water.
other. All the carbon atoms in this chain have the same attraction for the electrons, and so all share them equally. As a result, no one atom has extra charge, and the molecule is non-polar. Because of this non-polarity, these molecules will dissolve other non-polar molecules, like the ones found in butter. On the other hand, these molecules will not blend with polar molecules like water.
TRY IT!!
Here’s what you’ll need:
1. Four clear drinking glasses
2. Two ¼ cups of vegetable oil
3. Two ¼ cups of water (tap water is fine)
4. Two teaspoons of sugar
5. Two teaspoons of lard or coconut oil
6. Four small spoons for mixing
Here’s what to do:
1. Line up all four of your glasses
2. Pour one quarter cup of water into one of the glasses and one quarter cup of oil into another glass.
3. Add one teaspoon sugar to the glass with the water, and another teaspoon of sugar into the glass with the oil.
4. Mix them both well with two of your spoons, one for each glass, for at least two to five minutes.
What happened to the sugar in the water? Can you see any grains of sugar now? Write down what you saw happen.
What happened to the sugar in the oil? Did it dissolve? Write down what you saw.
Based on these observations, is sugar polar or non-polar? (Remember, polar things dissolve in water, while non-polar things dissolve in oil.)
Now for our next experiment:
1. Using your other two spoons, smear one teaspoon of lard or coconut oil onto the inside bottom and sides of each of the remaining two drinking glasses.
2. Add one quarter cup of oil to one of the glasses, and one quarter cup of water to the other glass.
3. Stir both glasses well for at least five minutes. Sometimes the lard or coconut oil is hard to dissolve, so be sure to mix for enough time!
What happened to the lard in the water? Did it dissolve? Is any still clinging to the bottom of the glass? Write down what you saw happen.
What happened to the lard in the oil? Is there any still clinging to the glass? Write down what you saw.
Based on these observations, is lard polar or non-polar? (Remember, polar things dissolve in water, while non-polar things dissolve in oil.)
MAKE UP YOUR OWN EXPERIMENT!
What else can you test in oil and water? Try other things you find in your kitchen, like salt, milk, juice, or baking soda. Write down everything you test, and what you observe!
REMEMBER: Some things you might test are complex mixtures of things that are polar AND things that are non-polar, so they not completely dissolve in either water or oil.
Here’s what you’ll need:
1. Four clear drinking glasses
2. Two ¼ cups of vegetable oil
3. Two ¼ cups of water (tap water is fine)
4. Two teaspoons of sugar
5. Two teaspoons of lard or coconut oil
6. Four small spoons for mixing
Here’s what to do:
1. Line up all four of your glasses
2. Pour one quarter cup of water into one of the glasses and one quarter cup of oil into another glass.
3. Add one teaspoon sugar to the glass with the water, and another teaspoon of sugar into the glass with the oil.
4. Mix them both well with two of your spoons, one for each glass, for at least two to five minutes.
What happened to the sugar in the water? Can you see any grains of sugar now? Write down what you saw happen.
What happened to the sugar in the oil? Did it dissolve? Write down what you saw.
Based on these observations, is sugar polar or non-polar? (Remember, polar things dissolve in water, while non-polar things dissolve in oil.)
Now for our next experiment:
1. Using your other two spoons, smear one teaspoon of lard or coconut oil onto the inside bottom and sides of each of the remaining two drinking glasses.
2. Add one quarter cup of oil to one of the glasses, and one quarter cup of water to the other glass.
3. Stir both glasses well for at least five minutes. Sometimes the lard or coconut oil is hard to dissolve, so be sure to mix for enough time!
What happened to the lard in the water? Did it dissolve? Is any still clinging to the bottom of the glass? Write down what you saw happen.
What happened to the lard in the oil? Is there any still clinging to the glass? Write down what you saw.
Based on these observations, is lard polar or non-polar? (Remember, polar things dissolve in water, while non-polar things dissolve in oil.)
MAKE UP YOUR OWN EXPERIMENT!
What else can you test in oil and water? Try other things you find in your kitchen, like salt, milk, juice, or baking soda. Write down everything you test, and what you observe!
REMEMBER: Some things you might test are complex mixtures of things that are polar AND things that are non-polar, so they not completely dissolve in either water or oil.
