Saturday, July 31, 2010

The Case for Basic Physics Education

Above: A course in basic physics often accompanied courses given to teachers in basic astronomy - ca. 1978-79, for the Caribbean Examinations Council.

It seems like eons ago, but at one time physics and mathematics were at the top of most high school curricula. This was in the early 60s, in the years after Sputnik (launched Oct. 4, 1957) as Americans grew concerned that Russia would overtake the U.S. in space – and seize the military high ground.

In high school science curricula, certainly for the college preparatory stream, it became common to offer the following in each respective high school year:

Freshman: Algebra I, General Science or Earth Science

Sophomore: Euclidean Geometry, Biology – including lab

Junior: Chemistry, Trigonometry- foreign language

Senior: Physics, Algebra II, foreign language.

It was also common practice in the 60s that even if a student was to split into the business or vocational stream, he or she at least had to take a General Science course and basic algebra. These were (rightly!) regarded as the minimum elements to be scientifically literate and numerically so.

Alas, as the decades have elapsed since then, science as well as math education have become victims to an over-crowded curriculum as well as the pernicious practice of teaching to the test – ratcheted up since Bush’s deformed ‘No Child Left Behind” – which actually left many millions behind and now Obama’s “Race to the Top”.

Physics, if taught at all, is now relegated to elite high schools like the Bronx Academy of Science, or special private schools. This is a national tragedy, especially since physics is arguably the most fundamental of the sciences. Without a background in physics, the citizen is at a severe disadvantage in coming to terms with the natural world, and will also be prey to any pseudo-scientific claptrap that comes along.

Today, if anything, the importance of physics has reached new levels, what with complex scientific problems also imbued in the political landscape. Problems such as: combating anthropogenic global warming (2010 is now on track to be the hottest year since records have been kept), energy efficiency and alternative energy sources, as well as more efficient modes of transportation. Outer space, while lacking the same high profile as in the 60s, is still relevant – given robotic exploration is more and more taking the place of manned expeditions. In addition, physics may well have to arrive at a means to eliminate an “Earth killer’ asteroid, if one should threaten Earth.

This leaves us to consider a plausible basic physics curriculum, integrating those elements that need to be mastered now. This is hypothetical, but I lay out one possible semester course below. The putative course envisions 5 hours per week, with three hours of class time, and two hours allocated to lab, per week.

Introduction to Newton’s laws of motion:

Simple experiments: using the Atwood Machine, inclined planes – and ticker timers or other devices to measure accelerations. Measuring the acceleration of gravity, g, from oscillations of a simple pendulum. Simple machines: the lever, the pulley. Mechanical advantage. Efficiency of simple machines.

Circular motion

Uniform circular motion demonstrated using simple models (e.g. ball affixed to end of string and rotated). Centripetal velocity and acceleration – including applied to planetary motion. Kepler's laws of planetary motion (simplified forms). Artificial satellites and escape velocity – how to attain a geo-stationary orbit. Locating satellites in the night sky, and predicting their future paths.

Thermal Energy

Difference between heat and temperature. Experiments to measure heat given off in a process. Heat transfer: conduction, convection and radiation – including simple experiments to demonstrate. Construction of a simple greenhouse - the greenhouse effect. The laws of thermodynamics (Zeroth, First and Second). Entropy – and everyday examples to illustrate it. Efficiency of thermal processes, transfers. Measuring heat capacity, specific heat capacity using a simple copper calorimeter.

Introduction to Electricity:

Concept of electronic charge, e, how measured. (The Millikan oil drop experiment) Demonstrating electronic attraction and repulsion using polythene rods and the electro-scope. Use of an oscilloscope to show and describe electron beams.

Experiments: designing and setting up simple series and parallel circuits – including with multiple components, as well as ammeters, voltmeters, resistances, light bulbs. Making a simple potentiometer. Calibrating an ammeter.

Electromagnetism: Showing how a magnetic field can be created using a current. Use of a galvanometer to measure an electric current induced by a magnetic in motion. (Or wire in motion relative to a magnet)

Basic Radioactive Decay and Processes:

Introduction to the types of ionizing radiation (where they occur, effects): alpha particles, beta particle, gamma rays. How to detect each, including setting up basic experiments using electroscopes, cloud chambers. Using cloud chambers to detect cosmic rays.

The hazards of ionizing radiations, and precautions. The basic equation of radioactive decay and examples, illustrations. Use of radioisotopes (e.g. C14) as tracers, and also to obtain the half-life of a material, and hence be able to estimate its age.

Simple nuclear reactions, both for fission and fusion reactions – representing each, e.g. H1 + H1 -> D2 + energy

The above set, based on my previous teaching of general physics courses – should be easily do-able in one semester. However, note that the delineation of topics assumes no time will be taken out for “teaching to the test”. The way I see it, one can either do that, or actually teach students, and there is an inverse relationship between them.

Yes, evaluations are part of the process – but that can be done with one mid-term examination, a possible project, and an end of term exam.

I invite feedback and advice from readers, including any changes they’d make to what I’ve put forward.

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