Experiment


Scientific Observation and Description

. . . those sciences are vain and full of errors which are not born from experiment, the mother of all certainty. . . .

Leonardo do Vinci (1452-1519)

We all think of ourselves as good observers. Yet there is much more to observation than meets the eye. It takes concentration, alertness to detail, ingenuity, and often just plain patience. It even takes practice! Try it yourself. See how complete a description you can write about a familiar object-say, a burning candle. Be "scientific" about this and start with an experiment. This means you should observe a burning candle in a laboratory, because it is a place where conditions can be controlled.
But how do we know what conditions should be controlled? Be ready for surprises here! Sometimes the important conditions are difficult to discover, but an experiment can be meaningless unless the conditions that matter are controlled. Here are some conditions that might be important in some experiments but are not important here:

(I) The experiment is done on the second floor. (2) The experiment is done in the daytime.
(3) The room lights are on.

Here are some conditions that might be important in your experiment:

(I) The lab bench is near the door.
(2) The windows are open.
(3) You are standing close enough to the candle to breathe on it.

Why is this second set of conditions important? They relate to a common factor: a candle does not burn well in a draft.
Important conditions are often not as easily recognized as these. A good experimentalist pays much attention to the discovery and control of conditions that are important.

PROCEDURE

First examine the candle carefully. Record ten observations in your notebook. Then light it, and record in your notebook ten more observations.Do not write these observations in paragraph form. Simply list the observations, being sure to number them. Leave space at the left margin of your paper before each of the observations. Additional information can be recorded there if needed.