Basic Laboratory Skills

I have been working on a laboratory course that can be taken as a self paced course at home or to be used by teachers in a small classroom, a cooperative school system, or even a regular classroom/laboratory setting. The idea behind this course is that you don’t need to have a lot of expensive laboratory equipment to be able to gain some essential hands-on laboratory experience and investigate a variety of chemical concepts.  Of course, you still need to be safe, and you still need to use good technique; but expense and specialized items should not be a barrier.

Thus, I have set off on this adventure, and have been very surprised at what I have found so far.  If you look at the current education standards there does not seem to be a list of laboratory techniques that students should be exposed to or master while in elementary, middle, or high school.  There is a lot of discussion about observation, understanding of concepts, and reviewing/analyzing data, but nothing related to a hands-on technique based experience.  There are comments about the importance of the laboratory experience in science, but not  anything specific about the fundamental skills that should be obtained.  Of course, this presents a challenge.  To do science, you need to have some basic skills.  But, we haven’t articulated what those skills are.

When I teach Kindergarten students, I tell them that scientists observe, measure, and predict.  Of course, this is a simplified version of the what we really do – but it boils the scientific process to the essentials.  Scientists observe their surroundings and phenomena.  Then formulate a hypothesis about what they are observing, and develop an experiment to test that hypothesis. During the experimentation, they gather data through more observation and measurement.  Finally, they analyze the information obtained, re-evaluate the hypothesis, and start the cycle again.  Also, at some point communicate their observations, findings and conclusions.

From this assessment of the process, three things stand out:

1) Observation skills are necessary.

2) Communication skills are necessary.

3) Measurement skills are necessary.

Hopefully, the first two skills are readily addressed through many aspects of the educational process.  Even very small children are making observations about their surroundings and are trying to communicate about what they see.  Parents and teachers are always working to improve these skills. These skills have to be refined a bit for the scientific process, i.e. note taking and scientific writing, but there are being worked on throughout the learning process.

Measurement is another matter.  For many of us, measurement comes naturally.  How many yards of fabric is needed for a pattern?  How many miles is it to the next town?  How tall am I?  Or, the old adage: measure twice cut once when building something.  However, due to changes in our society, measurement is not as routine as it once was.

Think about it.  We buy prepackaged sandwich meat, and don’t go to the deli counter.  Thus, if you had to cut/slice a ham for two pounds of lunch meat (and actually calculate how much that would be at certain price per pound), would you be able to do it?  How many people make a recipe from scratch?  (Do you know how many teaspoons there are to a tablespoon?)  When was the last time you bought nails, not to mention nails by the pound?

Even when we do measure, we don’t necessarily worry about precision.  If we are a little over or under, it usually doesn’t make a big difference.  But, in scientific measurement; precision is important.  Thus, those skills associated with measurement become very important.  Precision in measurement is communicated by the use of significant figures.  And, the concept of significant figures is lost on most individuals.

A number is written to communicate the measurement; 3 is fundamentally different from 2.54.  These numbers are communicating a different level of precision.  (2.54 is the number of centimeters to an inch; 3 is a rounded 2.54.) For most measurements, the level of precision is not of particular note or issue – unless we are paying for the difference.  For example:  Today’s price per ounce of gold is $1246.01.  This means every one tenth of an ounce is worth $124.60.  So, the difference between 3 and 2.5 is $623 – which is not trivial.  Thus, precision is important.

Measurement and the precision of the measurement are extremely important.  Thus, measurement and the precision of the measurement need to be taught and perfected as they are incorporated into both the language and the process of science.

So, get those students out there measuring with devices – rulers, thermometers, measuring cups, graduated cylinders, scales, balances, tape measures, protractors, etc.  Look at the precision, i.e. the markings on the devices.  Look at how precision impacts the result.  A little error in our measurement can result in huge problems later.  So, how that error gets magnified over time.  Look at the implication of error.  And, learn this essential skill.

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