For this week's experiment, we are going to make a ball of oil. Don't worry, this is not nearly as messy as it sounds. You will need:

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For this week's experiment, we will examine something that has caused problems for Moms throughout the ages. While washing up, someone leaves a towel hanging over the side of a sink full of water and mysteriously, the water all winds up on the floor.

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We are used to thinking of things as falling into the basic groups of solids, liquids, and gases. (In another experiment we will discuss a fourth state of matter, plasma.) In this experiment, we will examine a substance that sometimes acts like a solid and at other times acts like a liquid.

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Try this old trick for pouring soda with less foam.

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Science can be as simple as blowing bubbles in your milk.

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Make a tasty snack while learning about the science of butter.

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A simple science trick that is often used in magic shows

This week's experiment idea came to me while I was waiting for our lunch. The proper drink to go with your Memphis Bar-BQ is sweet tea. Now, you may not think that is unusual, but true, Southern sweet tea is a very different drink. The difference is based in the science of chemistry. To experience this, you will need:

2 pans
water
tea bags
sugar

WARNING: For this experiment, you will have to boil water. Be sure to get permission and be safe.

Put two cups of water into each pan. Heat the water until it boils. Add a couple of tea bags to each pan. To one pan, add 2 tablespoons of sugar. After boiling for a few seconds, turn off the heat and let them cool. Once they are both cooled, add two tablespoons of sugar to the unsweetened tea. Be sure to mark the pans, so you can tell which is which. Once the sugar is dissolved, taste each one. You will find that the tea that was sweetened while it was hot is sweeter. Why?

Your first thought might be that more of the sugar dissolves in hot water than in cold. That is why we only used 2 tablespoons of sugar. We want all of it to dissolve, even in the cold tea. With the same amount of sugar in each, they should both taste the same, right? Then, why is one sweeter?

The tea that was sweetened when it was hot now has a different kind of sugar in it. Yes, there are different kinds of sugar. The sugar that we normally use is called sucrose. Sucrose is a sugar that plants make and use to store energy. When you add the sucrose to the hot tea, a process called inversion takes place. The sucrose breaks down into two other sugars, glucose and fructose. This combination, called invert sugar, is about 10% sweeter than the sucrose it was made from. This process of inversion is very useful. Bakers use invert sugar to make confections sweeter. Bees use enzymes to do the same thing when they are making honey.

Now, true Southern sweet tea is SWEET! In addition to inverting the sugar, the hot tea allows you to dissolve more sugar in the tea. This combination is one that may be too sweet if you are not used to it. If you want to try the real thing, use about a cup of sugar for a quart of tea. Chill it until it is very cold and serve it over ice. Then all you need is some Memphis bar-BQ, some cole slaw, baked beans and some banana pudding and you are all set for a feast.

Greetings from our home in Jacksonville.  I had a marvelous trip to California, with marvelous audiences and lots of fun in the Mojave Desert.  You can see a little of my trip in this week's free video on Mirages.

I am also delighted to announce our first homeschool organization subscription for the Organization of Virginia Homeschoolers.  If your homeschool group would like an organization subscription, email me for information.  rob@krampf.com

This week's experiment is a favorite of mine, which won't be a surprise to anyone that has been on my experiment list for long.  To try this tasty experiment, you will need:

- 2 glasses
- carbonated soda
- ice cream

For this experiment, we will make two ice cream sodas.  Although both will contain exactly the same ingredients, they will be very different.

Start by filling one glass half-full of soda.  Then add a scoop of ice cream.  In the other glass, start by adding a scoop of ice cream, and then pour the soda into the glass.

You should notice a big difference between the two mixtures.  The glass where you added the ice cream first will have lots of thick, long lasting foam, while the glass where the ice cream was added after the soda has very little foam.  Why is there such a big difference?

There are two things that contribute to the difference in the foam.  First, the carbonated soda contains quite a bit of carbon dioxide gas dissolved in it.  It may seem strange to think of a gas dissolving in a liquid, but it is quite common.  If you watched the Watched Pot video, you may remember the bubbles of gas that appeared before the water started to boil.  Those bubbles formed from gases that were dissolved in the water.

The soda is supersaturated with carbon dioxide, which means that it contains more of the gas than would normally dissolve in it.  As long as the soda is undisturbed, the carbon dioxide escapes very slowly, but you can speed up the process by adding bubbles.  The bubbles provide more surface area for the gas to escape from.  As the gas escapes, the bubbles grow larger, providing even more surface area.  

You can see a very good example of this with an unopened bottle of soda.  If you give it a hard shake, and then open it, you are in for a mess.  Shaking the soda introduces lots of tiny bubbles into the soda, providing plenty of places for the carbon dioxide to come out of solution.  On the other hand, if you shake the soda, and then let it sit for a while before opening it, the bubbles will have time to float to the surface and pop.  In that case, when you open the soda, it stays in the bottle.

Another example of bubbles causing foam is the classic Mentos and Coke experiment.  The candy has a porous surface, which produces many tiny bubbles.  You can get similar results by dropping pieces of chalk into your soda, as it also has a very porous surface, but I don't recommend drinking the soda afterwards.

Now back to our ice cream.  Ice cream contains a LOT of bubbles.  In fact, a carton of ice cream may be as much as half air.  Those bubbles are important, as they keep the ice cream soft and smooth, instead of hard and crunchy like an ice cube.  

When you pour the soda into the glass first, microscopic bubbles from irregularities in the sides of the glass serve as a starting place for the foam.  Most of the carbon dioxide bubbles form and pop before the ice cream is added.

OK, so why is it any different when you add the ice cream first?  The ice cream has lots of tiny bubbles of air, so much more of the carbon dioxide comes out of solution.  If you taste the soda afterwards, you will find that it is quite flat, with no fizz left.  But, ice cream also contains chemical thickeners, to make it smoother and creamier.  As you pour the soda over the ice cream, some of the ice cream melts, letting the thickeners mix with the soda.  Just as they thicken the ice cream they thicken the foam, making it much firmer, and much longer lasting.  Instead of quickly popping, this time the foam stays long enough for you to enjoy eating your tasty treat.
   
So although both recipes use exactly the same ingredients, the order you add them makes a big difference, although both turn out quite tasty.  And keep in mind that an important part of science is that experiments should be repeatable, so you might want to repeat the test several times, just to be sure of your results.

Have a wonder-filled week.

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When is a change of state not really a change of state?

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Sand Angles

Learn structural engineering by making piles of candy.

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Attractive Cereal

They put WHAT in my cereal?

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Lint

How much science can there be in something as simple as lint? Quite a bit.

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Viscosity

A simple, scientific test to see how "thick" a liquid is.

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Even in the desert, you can make a cold, tasty snack with some common items and a little science.