Experiment A-1

Observation:  The Basis of Chemistry


Observation is the basis of all science.  Its importance for chemistry can not be exaggerated.  All primary information about the materials of the world must enter through our senses as must all secondary information.

Yet even today our senses are incompletely understood.  Some of our common sense beliefs about our senses are false or at least suspect.

Tasting SMALL amounts of chemicals provided crucial identification information to early chemists. However a few died young of poisoning.  Modern chemists have a safety rule to NEVER taste unknown chemicals.  Yet we all informally evaluate the chemical composition of our food and beverages by taste.

Chemists in the 20th Century routinely smelled vapors to assist doing chemistry. The author has noted that unlike a few decades ago, now new chemistry students in the United States often express strong reservations about experiencing any odor.  A segment of the population believes that all odors are harmful.  There is some evidence that may be BECOMING true!  (Some people now experience symptoms of illness from odors that caused no adverse effects for previous generations.  Perhaps the exposure to odors is similar to the effect of exposure to infectious agents?  A person who has been raised in an atmosphere free of a material does not develop a tolerance to it.  Just at the First Americans often fell ill and died because they lacked developed immunity to diseases brought by European settlers, current Americans may find odors which were common and harmless to their ancestors now cause illness to those raised sheltered from those odors.)

With restricted use of two of our senses, we rely more on our sense of vision.  While humans have always obtained most information via vision, that reliance has been augmented by the development of television, computer presentations, and other visual media.  But for the study of chemistry we would be well advised to remember that the material world does not reveal itself exclusively in the narrow-band of visible light.

Centuries ago the prominent chemist Joseph Black defined chemistry as the study of fire.  With the shifts in vocabulary meanings, his statement might be translated to chemistry is the study of energy.  Chemicals emit only a small portion of their energy as visible light.  Often a small portion is emitted as sound which we can detect with our sense of hearing.

A significant portion of chemical energy is admitted or absorbed as heat.  While poorly understood, our skin has nerves that can crudely detect temperature and energy flow, pain and pressure.  For example, feeling of cold and clammy might mean that the object was below room temperature and absorbed heat readily.

To detect much of the information coming from chemicals, we must supplement our senses with artificial nerves such as thermometers and Geiger counters.

Finally, a note about this web site:  The experiments and their introductions are intended to be studied in numerical order developing skills and understanding in a logical progression.  Each will assume you have learned the skills and safety procedures taught in previous experiments.  Skipping some experiments could greatly increase the danger of later experiments.


Because observing is the basis of chemistry, it is appropriate to start the study of chemistry with practice observing a chemical reaction.  We have all been observing since before birth!  So observation is not new to anyone.  But scientists have developed some habits that they believe optimize learning using observations.  These habits will be valuable whether you become the owner of your own business, a chemist, or just about any other vocation.

Get a notebook, preferably a bound notebook with pages sewn together, that you can make into your personal science journal.  Don't use loose scraps of paper which can get discarded or lost.  The purpose of your journal is to keep information forever.  Each page should be numbered.  Each entry should be dated and initialed or signed.  (Journals take on legal significance if you ever have to prove when you did something!)  Ink lasts much better than pencil, so use an ink that will be easy to read years in the future.  If you are not familiar with the information you should record in your journal, look at the screen on writing a formal report since much of the information needed for a formal report should be recorded first in your journal.

Obtain and observe a burning candle.  Caution:  Only proceed in a location where the experiment can be safely conducted.  Keep all other flammable materials away.  Don't leave any burning candle unattended.  Extinguish the flame if you get a phone call or any other interruption.  The world is filled with hazards.  Be prepared as possible for every potential accident.  Think ahead!  Playing with hazards often leads to tragedies.  This assignment is to OBSERVE fire, not to play with fire.  You are responsible for any damages or injuries you cause.  If a fire did start, what should you do?  If you are on fire, stop moving about, drop to the floor, and roll to extinguish.  Have ready a fire extinguisher, pail of water, or heavy towel or blanket to suffocate a small fire.  Have a phone nearby to call for help (911?).  If a fire gets out of control, warn everyone in the building.  Evacuate before it threatens to block exits.

Draw what the candle looks like, label the parts, and estimate measurements.  Use other senses beyond sight: What do you hear, smell, and feel.  (Remember a substance should be considered poisonous unless it is know not to be.)  Be careful to distinguish what is directly observable from interpretations that require educated guesses or information from common knowledge or other sources.  For example, to say the candle is made of wax is an interpretation, while describing its color, texture, and feel are observations.  In 1860, Michael Faraday, famous English scientist, gave a series of six Christmas lectures on a candle!  If Faraday could find enough to fill six lectures, don't believe you've exhausted all possibilities with a short list.  You might want to include observations after the flame has been freshly blown out.

Finally, scientists often construct formal reports for others to read.  Communicating technical information such as observations and findings is another skill used by scientists but useful for most others.  If you need course credit, use your observations recorded in your journal to construct a formal report.  If unsure what details should be included, read the screen describing a formal report.  Make sure your report is based on YOUR personal observations and not copied from someone else.

Optional Reading

AFTER you have completed the assignment you might want to read: Michael Faraday, Chemical History of a Candle, 1860 London, presented as a part of the Internet Modern History Sourcebook, a collection of public domain and copy-permitted texts, © Paul Halsall, August 1998.  Don't be discouraged if you missed some of Faraday's observations.  The idea is to develop your skills much as Faraday had achieved.


to next experiment
to Introduction to Chemistry menu
to ie-Chemistry menu
to site menu

created 11/7/2002
revised 11/7/2002
link update 9/12/2005
by D Trapp
Mac made