1 + 1 Does Not Always = 2
You might be a good math student, but you will have to be a good physics student to figure out this experiment.
You will need:
- large-size glass jar
- masking tape
- pen
- cup of sugar
- measuring cup
- paper towel
- drinking straw
- warm water
What to do: Place a strip of masking tape down the outside of the jar. Pour one cup of warm water into the jar and mark the level that it reaches on the tape. Then, add a second cup of warm water and, again mark the water level on the tape. Empty all of the water out of the jar and dry the inside of it with a paper towel. Now, pour one cup of warm water into the jar. Follow that with one cup of sugar. Stir this solution well with the straw and then check the liquid level on the masking-tape measuring strip.
What happens: The liquid level of one cup of water plus one cup of sugar does not reach the two-cup mark of the tape.
Why: If you caught the clue word, solution, when you were instructed to stir the sugar and water together, you probably know the answer. The substances in a solution fit neatly together, like puzzle parts. Instead of taking up their own space, the grains of sugar simply fill in the empty spaces around the water molecules to make something entirely new, a solution called sugar water...but less of it than you thought you would have when you added the sugar and water measurements.
The Talking Coin
You may have heard somebody say that money talks, but until you do this experiment you have probably never actually seen it speak.
You will need:
- plastic 2-liter bottle
- quarter
- cup of water
- freezer
- kitchen timer or watch
What to do: Put the quarter in the cup of water and place the empty bottle in the freezer for five minutes. When the time is up, remove the bottle from the freezer and, immediately, cover the mouth of the bottle with the wet coin. (It is important to completely cover the bottle's mouth with the coin.)
What happens: The quarter becomes a tongue for the bottle and begins to chatter to you.
Why: When the bottle was put into the freezer, the air molecules inside of it cooled and moved closer together. Since the air in the bottle then took up less space, it left room for extra air to flow in - so it did.
When the bottle was removed from the freezer, however, the air molecules inside of it began to warm up and spread out again. It's a great example of, "There was enough room for everyone to sit comfortably in the car until we all put on coats and it was crowded." Suddenly there was no room for the extra air molecules.
It is that "extra air" that is being pushed out of the bottle as the air warms that makes the coin move up and down as if it were talking.
"Boil, Boil Magical Water"
Would you believe you can boil water without using a stove? Here's the key to this old, well-kept secret.
You will need:
- clear drinking glass (a narrow one is easier to handle)
- water
- handkerchief-size square of cloth
- rubber band
- sink
What to do: Fill the glass about half full of water. Lay the cloth evenly over the top of the glass and push the center of it down into the water. Then, put a rubber band tightly around the top to hold the cloth edges against the sides of the glass. Turn the glass upside down over the sink. Some of the water may dribble out, but most of it will stay inside the glass.
Hold the cloth tightly around the neck of the glass, between the rubber band and the covered opening, and push down hard on the upside-down bottom of the glass.
What happens: The water starts to boil! (It may take a couple of tries to get the hand of this, but don't give up.)
Why: Of course, the water isn't really boiling, because there is no heat source. Actually, it is the air that comes in through the cloth when the water is squeezed out (by pressing on the bottom of the glass and tightly pulling on the cloth) that causes the bubbles - and makes it look as if the water in the glass is boiling.
What next: Once you can control the bubbling, use this experiment as a trick lie detector. Ask friends some questions and tell them that the water will boil if they lie, but won't if they tell the truth.
Note: You can make this trick more mysterious by tinting the water in the glass with food coloring.
Excerpted from 365 More Simple Science Experiments. Copyright (c) 1998 by Sterling Publishing Company. Reprinted with permission by BD&L
