Read Breakthrough Online

Authors: Jack Andraka

Breakthrough (21 page)

       
3.
 
Put the bone into your jar and pour your vinegar over it. You don't need to fill the whole jar; just make sure the bone is soaked. Now put the lid on the jar, stick it somewhere up on a shelf, and forget about it for the next three days.

       
4.
 
After the three days are up, carefully take your bone out of the jar and rinse it off. WARNING: When you open your jar you might be overwhelmed by a pungent odor. That's the vinegar. It won't hurt you, but it might make you feel like throwing up that chicken dinner you ate three nights earlier.

       
5.
 
Now that you've survived the smell, notice how different the bone feels in your hand. Try bending it again. This time, instead of feeling hard, it should bend like a piece of rubber.

Discussion

Remember in
Batman
when the Joker fell into the vat of acid and his face melted? Just like the liquid that messed up the Joker's face, vinegar is an acid, although a much weaker type, but it can do just as much damage if given the opportunity. That's because what gives chicken bones (and the bones inside your body) their superior strength is calcium. Calcium, or Ca, is an amazing chemical element needed for all living organisms, and is used in mineralization (the
way our cells soak in the minerals to help harden them) of bone, teeth, and shells.

However, it isn't without its weaknesses. In the case of calcium, vinegar happens to be its Kryptonite. While you were playing video games the last three days, the vinegar was working hard to strip the calcium out of the bone. Taking the calcium out of a bone is kind of like pulling out the stake from a scarecrow. All that is left is the soft bone tissue, leaving nothing to keep the bone hard. This experiment is also fun to try with an egg—the vinegar will completely dissolve the shell, leaving you with a see-through egg!

 

 

EXPERIMENT #3
Make Your Own Rock Candy

With all that talk of chicken dinner, maybe it's time for dessert? This experiment is the perfect excuse to consume vast amounts of colored sugar by making a supersaturated solution.

Materials

   
•
  
A clothespin or piece of string

   
•
  
One cup of water

   
•
  
Two wooden chopsticks

   
•
  
Three cups of sugar

   
•
  
A tall narrow glass

   
•
  
A medium-size pan

Procedure

       
1.
 
Take one chopstick and lay it across the top of your glass. Take the second chopstick and clip it to the first one using the clothespin, or tie them together using string. Position the chopsticks so that one is hanging straight down into the glass, without touching the sides or bottom. Put the glass off to the side.

       
2.
 
Pour the cup of water into the medium-size pan and heat.
When the water reaches a boil, begin adding the sugar, one quarter of a cup at a time. Stir until the sugar dissolves before adding more. You will notice that it becomes harder to dissolve the sugar as you add more and more. Be careful not to burn yourself!

       
3.
 
When you've added all the sugar, turn the heat off, grab some pot holders, and remove your pan of boiling sugar water from the stove. Set it aside someplace where it can cool and leave it alone for at least twenty minutes.

       
4.
 
After it's cooled, add some food coloring. Make sure you add enough coloring to make the water dark, as the color will fade quite a bit.

       
5.
 
Take your jar and remove the chopsticks. Carefully pour in the sugar solution until there is just a little room at the top. Now put your wooden chopsticks back into the glass, making sure that one is hanging straight down into the water without touching the sides.

       
6.
 
Find a nice quiet spot where you can leave your jar where it will not be disturbed by that curious cat of yours. Now you will need to wait between three and seven days.

       
7.
 
While you are waiting, you can look, but don't touch. It's fun to watch your sugar crystals as they grow.

       
8.
 
When the crystals have formed along the stick, take your chopstick out of the glass and eat your rock candy!

Discussion

This experiment works because boiling water can hold the sugar only when both are very hot. As the water cool and evaporates, small crystals of sugar will encrust the chopstick and sometimes the glass. These tiny seed crystals provide starting points for larger crystals.

The crystals grow because the supersaturated solution is unstable—it contains more sugar than can stay in a liquid form—so the sugar will come out of the solution, in a method called precipitation. Then, as time passes and the water evaporates, the solution becomes even more saturated and sugar molecules will continue to come out of the solution and collect on the seed crystals on your chopstick. The rock candy crystals grow molecule by molecule. Your finished rock candy will be made up of about a quadrillion molecules attached to your stick.

Did you know that rock candy is one of the oldest forms of candy and was originally used by pharmacists to make medicines? You can tell your parents that when they are giving you grief for eating so much sugar.

 

 

EXPERIMENT #4
The Mighty Unbreakable Bubble

Remember Glinda the Good Witch from
The Wizard of Oz
, who cruised around all over Munchkinland in that hovering magical bubble thing? Well, with this experiment, we will use the power of science to finally pull the curtain back to reveal the magic behind the mighty unbreakable bubble.

Materials

   
•
  
Two tablespoons dish soap

   
•
  
One cup of distilled water

   
•
  
Cotton gloves

   
•
  
A bottle of bubbles (you know, the one with the little wand that you can get at your local supermarket)

   
•
  
One tablespoon Karo syrup (check the syrup section at your local grocery store)

   
•
  
A mixing bowl

Procedure

       
1.
 
Pour the cup of distilled water into the mixing bowl.

       
2.
 
Add two tablespoons of dish soap and one tablespoon of Karo syrup and stir until everything is mixed up.

       
3.
 
Slip on your cotton gloves, take the magic bubble wand out of your bubble container, dip it into your soapy mix, and begin blowing bubbles. The goal is to make really huge bubbles.

       
4.
 
These are no ordinary bubbles. See how you can gently catch the bubbles and tap them up or down with your gloved hand? Watch them bounce off the glove and back into the air!

TIP: This experiment works best on humid days when there is a lot of moisture in the air and the walls of the bubble have more support. Experiment to figure out what materials make the bubbles bounce the best. Try your knee or hat. Or even your annoying brother's or sister's head!

Discussion

In normal bubbles, the soapy mixture on the outside is actually made of three layers: soap, water, and another layer of soap.

What causes these normal bubbles to pop so easily is that, over time, the water that is trapped between the layers of soap evaporates and the force of gravity causes the superthin walls, which can measure as little as a millionth of an inch, to collapse.

And that's only if you are lucky enough that a bubble's other worst enemies—dirt and oil—don't get to it first.

The reason our unbreakable bubble will bounce off a surface that would normally cause it to break is because the corn syrup found in the Karo gave it an extra layer of support, making it thicker. This thicker wall keeps the water inside from evaporating as quickly, which gives the bubble its impressive staying power. Wearing the gloves helps out by safeguarding against dirt and oil.

 

 

EXPERIMENT #5
Dr. Jekyll and Mr. Milk

One of the things that has always fascinated me about science is how it can take all these seemingly boring, ordinary, everyday items and reveal a deep, explosive underbelly that was hiding beneath the surface.

In the Dr. Jekyll and Mr. Milk experiment, we will take our well-known morning cereal companion and then, through the powers of science, make an amazing display of colors by adding one simple ingredient—dish soap.

Materials

   
•
  
A large dinner plate

   
•
  
Milk (whole or 2 percent)

   
•
  
Cotton swabs

   
•
  
Dish soap

   
•
  
Food coloring (red, yellow, green, and blue)

Procedure

       
1.
 
Pour milk onto your dinner plate until the bottom is completely covered, but not so much that it spills over onto the table.

       
2.
 
Give the milk a few seconds to settle.

       
3.
 
Add one drop of each of your four colors of food coloring to the center of your milky plate (the order of the colors is up to you and doesn't really matter).

       
4.
 
Take just a single drop of your dish soap and drip it onto the end of the cotton swab. Gently dip the soapy end of the cotton swab in the middle of the milk. Now hold it there for twenty seconds and watch the amazing display of color.

Discussion

This experiment is all about the violent clash between the milk and the dish soap. The milk contains vitamins, minerals, proteins, and, most important (at least for our experiment), tiny droplets of fat.

If you have read
The Strange Case of Dr. Jekyll and Mr. Hyde
, you know that those names apply to polar-opposite personalities trapped inside the same person.

Dish soap has similar “bipolar” characteristics (remember,
bi
means two). The soap has one personality, or characteristic, that is hydrophilic, meaning it
loves
water. In fact, it loves it so much it melts right into it and dissolves.

Then there is the other side of dish soap, its inner Mr. Hyde, that absolutely despises water. It's hydrophobic, or water-fearing, and is so freaked out by the water that it desperately latches on to the fat in the milk, in a violent, thrashing sort of way. It is this reaction that
makes this experiment so cool.

Did you ever hear lifeguards talk about the danger of trying to save someone who is drowning? That's because the drowning victim can become so full of adrenaline that they might actually pull even an accomplished swimmer down with them.

The same principle is at work in our pan of milk. The soap is so afraid of water that it scrambles to grab onto any piece of fat it can find, and once there, it holds on and contorts the fat in all kinds of crazy directions. The only role of the food coloring is to make this spastic interaction visible.

After a few minutes, the soap will become evenly mixed with the milk and the action will slow down until it eventually stops.

TIP: Experiment by dabbing your soapy cotton swab at different places in the milk. What happens? Also, how does it change when you switch from whole milk to 2 percent?

And one quick word of warning: Remember, no matter how thirsty you might become, milk that has soap and food coloring in it might look delicious, but drinking it will cause you to gag. Seriously.

 

 

EXPERIMENT #6
It's Potato O'Clock!

Have you ever
really
needed to know the time, but when you looked all you could find were potatoes?

We are all aware of the many purposes of the potato—mainly, to be next to our cheeseburger and slightly to the left of our pickle—but did you know that if you are in a pinch you can use your potato as a battery?

Materials
(check your local hardware store)

   
•
  
Two ten-centimeter lengths of thick copper ground wire

   
•
  
Two large galvanized zinc nails

   
•
  
Three alligator-clip wires

   
•
  
Two fresh potatoes

   
•
  
A simple low-voltage LED clock that functions from a one- to two-volt button-type battery

Procedure

       
1.
 
First, open the clock's battery compartment and remove the button battery.

       
2.
 
Look inside and find the two battery connections. One should be marked with a plus sign and the other with a
minus sign. That is where you will be hooking up your potato.

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