Problem Solving

Problem-solving skills are important, or so say those who moan about the lack of such in today's college graduates. And Southern Man had an interesting experience with problem-solving skills today.

The college physics class he's teaching is studying fluids, pressure, density, and so on. Southern Man handed them a worksheet today (for small-group work; noisy but fun) which, among others, contained the following problem:

A blimp, with air bag volume 12000 cubic meters, cruises through the air. The blimp carries a total mass of 2000 kg. What is the density of the lifting gas within the blimp?

It's a straightforward calculation involving the relationship between volume, mass, and density. Every group completed this problem; most did so correctly.

A bit further on they encounter a second problem involving the same principles:

Estimate the mass of the air in this classroom.

Not a single group attempted to solve this problem.

Do you see how these problems are the same, and how they are different?

The similarity is that the exact same knowledge - the relationship between volume, density, and mass - is required to solve both problems. The difference is that the needed volume was given in the first problem, but not in the second. Not one student had the wit to get out of their chair and walk off the length and width of the classroom to acquire the information they needed to complete the problem. Not one. Instead they stared helplessly, at a complete loss as to how to proceed, and then moved on to the next problem on the worksheet.

Southern Man weeps for the future of our nation.