Saturday, January 30, 2010

Hands-On Labs are Not the Answer

From the beginning of science labs in education in the mid-1800s, they've been hands-on labs. Until the latter half of the 20th century, the only other sort of lab was the paper-and-pencil lab. Some of you may not have encountered these desktop labs.

In a paper-and-pencil lab, the instructor hands out copies of laboratory "data," which may have been created from equations and not taken from real experiments. Students then fill in provided tables with the data and calculations based on that data. Finally, they answer questions about the results.

What are the benefits of paper-and-pencil labs?
  • low cost
  • minimal time required
  • high safety
  • lab technique does not affect results
What are the problems with paper-and-pencil labs?
  • no experimental design
  • likely to have unreal data
  • no kinesthetic experience
  • no visual experience
  • data not dependent on student technique
  • data not dependent of student judgment
I'm sure that you can add to these lists. You'll note that these features, except for lack of visual experience, match those of computer laboratory simulations being hawked by a wide variety of vendors, instructors, and amateur scientists. With simulations, the visual experience is generally poor, being limited to cartoon-like animations.

With so many defects in these labs, whether pencil-and-paper or simulations, you can see why so many educators have pushed back very hard to the point where they insist that only hands-on labs can be appropriate for science education. It's a natural reaction by those appalled by the large infusion of simulations into the laboratory part of many science curricula.

However, these hands-on purists are throwing out the baby with the bath water. By denying any lab but a hands-on lab, they're making advances in science education difficult and limiting their student experiences severely.

They should be searching for means to make new advances in technology available in science education. The goals must include the following.
  • lower cost of true science lab learning experiences
  • improve safety of science lab experiences
  • expand range of science lab experiences available to students
  • use student class and homework time more efficiently
  • provide exposure to the nature of science and all that it implies
Hands-on labs can be great learning experiences. Those that extend over many periods and involve iterative redesign and exploration can open up new vistas in students' imaginations. Instructors should not give these up entirely. However, recognize that such experiences are time-consuming and expensive. Usually, they require that students work in groups, and some in any group may opt out of the experience, just tagging along for the ride.

On the other hand, many hands-on labs are merely exercises in lab technique. How many students will find pipetting techniques valuable in the future? Other hands-on labs have been structured as "verification" labs, a class of labs that was railed against by F. W. Westaway nearly a century ago and by Carl Sagan much more recently. Students know all of the science and the numerical result expected before entering the lab. They are simply to verify this information.

Technique and verification labs do not teach science. They are a waste of time and money. Worse, they give students the impression that science is dull and uninspiring.

What's to be done? One way to view the options is to look at the Mars Rover program. It's real science, and not science pedagogy. So, you must be careful about drawing too close of an analogy. I'll be posting more on this analogy soon.

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2 comments:

Thalassamania said...

Why is technique a waste of time?

I've had to pipette many times in real life.

I've also had to do real dissections, the results of which were critical to real questions. Without having had time and practice and imperfect specimens to have worked on in high school and then college "labs" I would not have had the skills to do real science in the real world later on.

Harry said...

Thank you for your comment. As I've indicated many times, those who will be doing science work (scientists, lab technicians, science educators, et al.) should have as much real lab time as they can get. These people form a small minority of all students.

After all, how many people will use pipets in real life? Do construction workers or corporate managers? I could make a very long list of professions, but you get the point.

Moreover, the volumetric pipet is an ancient piece of glassware that is becoming less common in labs today. And, you can learn good pipet technique in a hour or less.

If techniques that might be used later in life are so valuable and should be taught in high school, why was I not taught to solder copper pipes or fell trees? I certainly have used those skills many, many times although I'm neither a plumber nor a lumberjack. And these skills take a bit more time to perfect than using a pipet.

I wasn't taught excellent computer programming skills either. Yet, I used those skills to make a living for a while, and they take years to perfect. In fact, no student graduating high school when I did, to my knowledge, learned anything at all about computer programming.

I thought it was clear why learning 19th-century lab technique is a waste of time. Apparently not to everyone. So, I'll recapitulate.

A small minority of students benefit from learning technique. For the most part, they can learn in college or on the job without loss of the benefits.

For the rest of us (not including me because I obtained a PhD in chemistry), the time spent learning these old-fashioned techniques would be better spent learning to think. For most people, learning technique is dull and inapplicable to anything in the rest of their lives. Learning to think is exciting and highly applicable.

There's just no contest. Giving a single example as you've done proves nothing.

I could say much more but the above should suffice.