Physics and Engineering

Is our education system teaching kids how to leverage their knowledge in the real world? If not, how big is the gap and is it even worth bridging the gap?

I and my 13 year old Sun have been studying about fluid pressure (Pascal's law) and its use in the amplification of forces at the cost of velocity advantage.

The diagram above is the typical diagram we see in school physics books. It starts with the concept and ends with a barrage of numerical problems of varying level of convolution. The competencies required to solve such numerical problems are:

• Comprehension skills - to decode the prose and parse out the known and unknowns variables
• Modelling skills - to build an algebraic model of one or more equations using concepts
• Model simplification - to simplify the model and arrive at the final solvable equality
• Numerical skills - to add, multiply, divide and get the final answer.

The above skills are important, but unfortunately we devote and pour all our energies in honing the child's skill in the above four competencies. Why? because the exams considers them as a measure of learning. In the process, have we not completely overlooked the training of how knowledge can be realized physically and in real world problems?

One of the problems I and my Sun spent three days solving was the following:

"Build a hydraulic lever, which should be capable of lifting a 1 kg weight to a height of 2 cm."

Over dinner, it was decided that we will use two syringes as hydraulic pistons and a small part of IV drip tube as the connecting pipe. Looked like a solvable problem. As we started building the contraption, we were soon faced with issues which had no mention of, in the textbooks.

• Upon simple calculations, we realized that the smaller syringe would need to move 14 cm to raise the 1 kg weight 2 cm through the bigger piston - hmmph.. the smaller syringe barrel was at most 4 cm (usable). We can't make this work, unless we incorporate some kind of a one way valve system, which would enable us to pump the small syringe multiple times, raising the bigger piston by tiny amounts in each push.

• The second challenge was how do we build the one-way valve. This was a difficult situation. Upon quite a bit of brainstorming, we decided to use ball-bearings inside the syringes. Off we went and bought half a dozen ball bearings from a neighborhood cycle shop. We soon realized that this was not a workable solution.. the valve was not water tight enough. After struggling for nearly two days and coming this close to giving up, it struck us that aquariums use tiny one way valves for air pumps! With our hopes freshly fueled, we ran to a pet shop and got ourselves few of the air valves. Perfect! they worked like a charm!

• We then went about attaching the pipes. But before we could attach the pipes, we needed to make holes in the syringes. How do we make the holes - hot poker, screws, cylindrical file? As simple as it sounded, we ended up spoiling three syringes just because the holes were not round enough and resulted in leakage. Trying out few more options, we finally found that we have to drill the holes using Dremmel and in very small iterations, always checking if the diameter of the hole is just right for fitting the tube.

• We were going good. The warm feeling of an achievable goal was exciting. All connections made.. and now it was time for testing. First taste of failure! The pipe connections, especially the ones we had fitted by drilling were still not water tight at pressure. Secondly, once the water starts filling the big cylinder, how do we drain it out for another run?

• Many options were considered, theoretical ones like a small tap to highly practical ones like a paper clamp. A small tap which fits an IV line had availability challenges, while a paper clamp was an ugly. In the end two feasible and practical options emerged - either we use the IV tube pincher or make do by attaching a one way valve to the end of the reservoir drain pipe. We went with the later options.

• Last but not the least, we needed to fabricate a stand on which to mount the experiment. So wwwrrr... came out our saw, wooden planks and an L shaped stand was created on which the syringes were mounted by clamps.

I realized that more than just the concepts and solving problems, this experience taught us how to be creative and pool in experiences from many other fields to built a working solution within reasonable constraints (which makes it different from laboratory experiments, where it's more of point, click and assemble). 

It also reinforced a valuable lesson that talking and thinking on paper is a lot different than what is takes to make it work.

Overall a thoroughly enjoyable time spend with my Sun, teaching science and introducing him to engineering.

PS: This is what I found on the difference between Physics and Engineering..

Physics is a scientific discipline. It normally is an analytical subject which provides general analysis of nature to make us understand how universe works! 

Engineering is a practical discipline which takes the scientific knowledge and develops new thing or new ways of doing things i.e. processes! Engineering is considered as a skillful, creative and professional discipline which acquires knowledge from different fields and applies it to design and build machines, processes, electronic devices etc.