Building your own laboratory
THOMAS J. WDOWIAK
You don't have to be a rocket scientist to have a real scientist's lab. Over the next year, Dr. Thomas Wdowiak will help you build your own laboratory. Each month Dr. Wdowiak will help you build the equipment to conduct one experiment. At the end of the year, you'll have a complete laboratory.
And almost everything you'll need will be found in your own home or easily purchased at a supermarket, a home improvement or a Radio Shack. ''The most important piece of equipment you'll need is a notebook to record your experiments,'' Wdowiak says.
The first experiment is a demonstration of chromatography, a process in which a mixture of chemicals (in our experiment, we use inks) is carried by a liquid or gas (we're using a liquid - in this case vinegar) and is separated into components.
The pattern of these components that forms on an absorbent medium (we're using a piece of this newspaper) is called a chromatogram. Scientists use chromatography to discover what ingredients go into all sorts of things - from the molecules like a plant's chlorophyll to the DNA in people.
What You'll Need
Tape the strip of newspaper to the center of the cardboard so that it hangs down into the middle of the glass - the newspaper should just touch the bottom of the glass when the cardboard is placed on top, and it should not touch the sides. Use your scissors to trim the strip from the bottom until it fits.
Now that the strip of paper is the correct length, remove the strip from the glass and lay it on the table - do not remove it from the cardboard.
Place the strip of newspaper into the glass - the bottom of the paper should be in the vinegar, but not the lines.
Wait about an hour, remove the strip from the solution and allow it to dry.
Why? Each pigment molecule has a different size, so smaller molecules generally move more quickly up the paper than larger molecules. Also, there is the difference in how strongly the molecules are attracted to the paper and the vinegar. Consequently, they will move up the paper differently. In this experiment we can see how paper chromatography can separate out molecules according to their behavior.
You can do the same experiment using fruit juice, food coloring or just about anything that can be dissolved in liquid. Try other kinds of liquids instead of vinegar, like a little dish detergent dissolved in water, or with your parents supervision, some rubbing alcohol with or without water.
Remember, it's an experiment.
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