Breakthrough (22 page)

       
3.
 
Take your first potato and poke one end of your copper wire inside it at least half an inch. Now find a place as far away from the wire as possible to stick your nail into the potato. You don't want them to touch! I'll explain why later.

       
4.
 
Repeat step 3 with potato two, inserting the copper wire and nail—again, as far from each other as possible.

       
5.
 
Now use one alligator-clip wire to connect the copper wire of your first potato to the plus connection in the clock.

       
6.
 
Grab another alligator-clip wire and, this time, use it to connect the zinc nail of your second potato to the negative connection in the clock.

       
7.
 
Then take your third alligator-clip wire and use it to connect the zinc nail of your first potato to the copper wire of your second potato.

       
8.
 
Now look at that! Your clock is running on nothing but the magic of the mighty spud!

Congratulations! You just made an electrochemical battery, also known as an electrochemical cell. In other words, with the power of the potatoes, you were able to convert chemical energy to electric energy by inspiring something called a spontaneous electron transfer.

In the case of the potatoes, our favorite starch acts as a kind of buffer between the power from the zinc in the nail and the copper wire. The juice from the potato helps transfer the electrons over the copper wires of the circuit, which channels the energy into the clock. If your potatoes are fresh enough, you can actually run your clock on potato power for months!

NOTE: If the zinc and the copper touched inside of the potato, they would still react, but they would only generate heat.

Your friends may be chuckling at your potato clock today, but just wait until that zombie apocalypse hits, there is a shortage of batteries, and you are the only one who is able to tell time—we will see who is laughing at your amazing potato clock then!

 

 

Have you ever wondered if science sucks? The answer is . . . sometimes. Using only simple household items, you will create your very own vacuum, capable of sucking up water.

   
•
  
A drinking glass or other clear glass container

   
•
  
A ceramic plate

   
•
  
A candle (make sure your candle fits inside the glass)

   
•
  
Food coloring

   
•
  
Matches

   
•
  
Water

       
1.
 
Pour water onto your plate until the bottom is covered.

       
2.
 
Add a few drops of food coloring to the water and mix until the color is evenly distributed.

       
3.
 
Put the candle in the middle of the plate and ask a parent to light it.

       
4.
 
After waiting at least a few seconds, place your glass upside down over the candle so it is completely covered.

       
5.
 
Watch what happens when the candle goes out . . .

Once the cup is covering the candle, the flame will eventually run out of oxygen and go out. While the candle was burning, it was heating the air inside the glass, and heated air expands. You may even notice some bubbles escaping from the bottom of the glass. But when the flame has gone out, the air begins to cool down, and cool air contracts. This contraction is what pulls the water from the plate into the glass.

 

 

Have you ever suspected that something dark and mysterious has been growing where your brother throws his disgusting dirty socks even though everyone has reminded him that his laundry basket is only a few feet away?

Now with the Mad Scientist experiment we finally have the tools to prove your suspicions.

   
•
  
A petri dish of agar, a gelatinous substance made from seaweed that bacteria love to eat (if you search online, you should find some for under ten dollars. You can also use agar powder. Just add water or fruit juice to make a gel.)

   
•
  
A few sheets of old newspaper

   
•
  
A cotton swab

   
•
  
A disgusting surface

       
1.
 
Grab the cotton swab and find a surface in your house that warrants further investigation. I always like to pick the most disgusting surface I can find. Take your cotton swab and
gently rub it a few times against the surface you choose.

       
2.
 
Rub the swab over the agar a few times, then close the lid and seal up the petri dish. Be sure not to open the dish again, as you don't want the bacteria getting out. Also, make sure you throw away the used cotton swabs.

       
3.
 
Now find a warm area where your petri dish won't be disturbed and let it sit for two to three days.

       
4.
 
It won't be long before those tiny invisible bacteria will grow large enough to be visible to the naked eye. Soon you should see a whole bunch of new life growing.

       
5.
 
It helps to write down your observations from day to day or take cell phone shots so you can remember the changes.

       
6.
 
You can repeat the experiment by swabbing all kinds of surfaces. If you really want a scare, try under your fingernails. You wouldn't believe what creatures have been living rent-free under there!

NOTE: When finished, carefully get rid of the bacteria by wrapping up the petri dish in old newspaper before throwing it in the trash. Remember, don't open the lid of the dish—you don't want the bacteria you've been growing anywhere near you!

Now that you've seen what is living in your brother's room, you might
feel the impulse to call a hazmat crew or the Centers for Disease Control. Don't do it! At least not yet.

With the agar plate and a warm climate, we provide the perfect environment for the bacteria to grow. If you watch long enough, eventually they will grow into individual colonies, each cloning the original.

The truth is that while, yes, your brother needs to work on his hygiene, bacteria are everywhere.

Bacteria are a member of a large group of unicellular microorganisms that have cell walls but are missing an organized nucleus. A gram of soil typically contains about forty million bacterial cells. A milliliter of fresh water usually holds about one million bacterial cells. Our planet is estimated to hold at least five nonillion bacteria. Get the point? Bacteria are
everywhere
!

Don't freak out! Our immune system usually does a great job of making sure these bacteria are harmless. That isn't to say that your brother's room shouldn't still be condemned as a toxic waste site.

 

 

Have you ever looked at your smug sibling after he just spent an hour and a half in front of the mirror making his hair oh so perfect and wished you could make a rain cloud burst open above his head at just the right time?

Well, check out this really cool experiment where you can make your own real rain cloud in a bottle!

   
•
  
A plastic water bottle with a sports cap that pops open and shut

   
•
  
Matches

   
•
  
Warm water

       
1.
 
Pour about an eighth of a cup of warm water into your plastic water bottle.

       
2.
 
Put the cap back on, but don't close the top. Now, have a parent light your match and quickly puff it out so it smokes above the bottle. Suck the smoke into the bottle by squeezing the bottle gently and releasing it with the mouth of the bottle in
the smoke. After a few good squeezes, close the cap.

       
3.
 
Take your shut bottle and squeeze and release a few times.

       
4.
 
Notice that when you squeeze the bottle, there is no cloud. However, when you release the bottle, a cloud should appear.

TIP: Try mixing up the water temperatures, switching between hot and cold, and see what that does to your cloud.

Clouds need only three things to form: water molecules, cloud condensation nuclei (that could mean dust or air pollution), and changes in temperature or air pressure. That's why clouds are more likely to form outside when it's cold.

When you squeeze the bottle, the pressure increases. This causes the temperature inside the bottle to rise. Then, when you release the bottle, the pressure decreases. This causes the temperature inside the bottle to fall and the water molecules to condense and stick together around the smoke. And that's how you make a cloud in a bottle.

 

 

There is this old Andraka family saying that there are really only two types of people in the world: those who make the motors and everyone else.

According to legend, that saying has been passed down from generation to generation since Great-Great-Great-Grandpa Arnold Andraka used the motor he invented made from a broken wagon wheel, a quarter tablet of Alka-Seltzer, three rusted coat hangers, and a complicated series of pulleys and levers to sail his mighty vessel across the seven seas.

Okay, maybe that isn't exactly an old Andraka saying. Actually, I just made all that up, but really, this is a
very
cool experiment! And if I actually had a great-great-great-grandpa Arnold Andraka, he would totally agree.

   
•
  
Three feet of copper wire

   
•
  
A magnet

   
•
  
Two safety pins

   
•
  
Electrical tape

   
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A D-cell battery

       
1.
 
Position your D-cell battery on its side. Clip a safety pin to each end. If you have trouble attaching them, use electrical tape so that the head of each safety pin is against the battery's terminals, with the other end of the safety pin (the one with the loop) sticking straight up.

       
2.
 
Place your magnet on top of your battery.

       
3.
 
Take your wire and make it into a circle by looping it around a couple of times, leaving the two ends of the wire pointing out in opposite directions. You may want to wrap the ends around the coil a few times to secure it, but be sure there are a few inches sticking out. Make your coil small enough that when you balance the two ends of the coil through the loops on the safety pins, the coil just clears the magnet.

       
4.
 
Thread the two ends of the wire through each loop in the safety pins. When your coil is in position, give it a push, and the circle of wire should start to rotate.

WARNING: If you use a thin wire, depending on the strength of your current, it can get extremely hot! So be careful.

This experiment is a fun way to see how to make a simple version of
the motors found in everyday household appliances, tools, and many of the other devices that make your life easier. It's a great experiment for aspiring scientists, because once you get the fundamentals down, you can check online to discover even more complicated motors that you can use to chase around the family pets.

Here is a handy trick to quickly divide large numbers by 9. Let's try dividing 32,121 by 9.

Start by writing down the first digit of your dividend, in this case 3.

Next, you are going to add 3 to the next number in the dividend, in this case 2. Write down 5.

Now add 5 to the next number in the dividend, 1. Continue adding this way until you reach the end.