Paired Word Experiment with Plastic Rods

One experiment that has worked quite well when I was teaching junior high school science classes was one that helps students practice using their observational skills and the scientific method. You can print pairs of words on an address label and later peel and paste them on a large index card.

The word pairs need to be about 16 point Times New Roman, although some other fonts may work, but can affect the experiment. All the words must be type in capital letters. One of the word pairs must be in Red and the other in Blue. You only need two or three word pairs on the label. Some examples of word pairs are:

RAW HIDE
CODE MAP
RAW HIDE
SIDE RAIL
TIGHTLY BOXED
CARBON DIOXIDE

You can use glass rods, but plastic works well and is safer. The rods should be large enough so they are not easily swallowed, but sternly warn everyone not to put them in their mouth. If you want extra safety, you can drill a hole in one end large enough to thread a large string through (Note: I have dipped them in rubbing alcohol before using them, to clean and partly sterilize them and also to make them taste bad). The rods are about 1/2 to 3/4 inch in diameter. They must be bigger in diameter than the printed words in 16 point font. You can find companies that sell plastic rods in most major cities and they can cut the rods into the proper length for you if needed. The rods should be cut into lengths that are long enough to cover at least one word pair, but it is fine if it covers a little more than one word pair.

You should make enough word pair cards for everyone in the class and a few extra, you can use any of the word pairs listed above or you can make word pairs out of the letters shown in the graphic.

I have students clear their desk and then pass out the cards face down and tell the students not to turn them over until I tell them. I then pass out the plastic rods and tell them to leave them on their desk also and wait until told. I tell them that some of them will know what is happening in this experiment immediately, but not to say anything to anyone because we want to see who can't figure it out. I tell them that when told they will turn over the cards and look at the pairs of words on the card through the class rod by holding it over a word pair and slightly above the card and words. I will give them a very short amount of time and then ask: "Those who think they know what is happening- raise your hand, but don't say anything." Then you can ask individual students to tell you what strange was happening and then to tell you what their "hypothesis" is about what happened.

Some will tell you its the letters, some will tell you it is the color (This is what you actually want them to think). You can then tell them that right at the start of this process any reasonable hypothesis is fine, but you will need to think of some way to test the hypothesis. Some may come up with the idea to turn the paper around, some may say to write the words in different colors. You can then ask them to try some of these ideas.

By going through this process they are discover something odd happening, make observations, state a possible hypothesis, and testing their hypothesis, and come to a conclusion. The actual reason for the red word not turning upside down is that it was made with symmetrical letters and it has nothing to do with the color. You can then ask them to write down the word "MOM" on their own paper and look at it through the glass rod. As they do this I tell them: "Your mother will like doing this part of the experiment!" (It turns into: "WOW".)

This experiment when completed gives you the opportunity to then talk about "symmetry" in science. People have "bilateral" symmetry for example. They have an eye on each side of their head, they have two ears, two nostrils, etc. Even though they don't have two hearts, most of our bodies are symmetrical. You can talk about starfish that have "radial" symmetry. You can also talk about how light passes through the plastic rod and how it reflects in mirrors and you can point out how an ambulance has the word "ambulance" spelled backwards on the front of the ambulance so that as a driver ahead of the ambulance looks into the rear view mirror, the word ambulance will be readable by the driver ahead of the ambulance.

This lesson then can become a springboard into other topics of science.

SECOND WARNING
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For young children this is even more of a danger that they might put the rod into their mouth. You can do this same experiment in small groups and it will make monitoring them easier. You can also set up lab stations and assign "student monitors" to the stations having them keep students from putting the rods in their mouth. Of course you can also warn students about the danger of spreading germs, which is also true. Take extreme care with any experiment.