20140508

Presentation: Cuesta College modern physics laboratory equipment proposal

(Splash screen: cathode ray tube television and magnet.)

This is a grant proposal presented to the Cuesta College Foundation for purchasing equipment for a new laboratory component to the modern physics curriculum.

First, explaining the need for this new equipment.

Cuesta College has a two-semester calculus-based introductory physics lecture with a laboratory component for engineering and physics majors. The terminal third semester covers modern physics but is a lecture-only class, with no laboratory component.

Recently an Associate Degree for Transfer has been recently established between California Community Colleges and the California State University system, where students who complete their community college coursework can be guaranteed admission to a state university campus with junior status. In order for the physics curriculum at Cuesta College to be recognized as an Associate Degree for Transfer program, the third semester of modern physics must now include a laboratory component, which has historically never been offered before at Cuesta College.

Second--with the pressing need to start-up a laboratory course in modern physics at Cuesta College--what type of equipment would this require?

Modern physics is "modern" not just in the sense of 20th-century scientific discoveries, but also these discoveries were harbingers of the technology used everyday in our modern 21st world.

Nobel physics prizes were awarded in recognition of the significance of these discoveries, and a "modern" physics laboratory should allow students to experience what these physicists experienced in making their breakthroughs. Let's consider a sample of these Nobel physics prize winners, their experimental findings, and what it would take for students to recreate these discoveries in a modern physics laboratory setting.

Here's J. J. Thomson, the 1906 Nobel physics prize winner at his element in his laboratory, investigating the effect of magnetic fields on electron streams.

Measuring the behavior of this electron stream established that electrons were particles with a given ratio of mass per charge. In fact, this experimental set-up is the basis for cathode ray tube televisions, where a stream of electrons down a tube hits a screen, and using magnetic fields to sweep this beam across the screen can build up a moving image. So when students are recreating Thomson's experiment, they are also experiencing hands-on principles of early television technology. Certainly we can't have students building a television from scratch in order to measure electron mass/charge ratios, so it is necessary to purchase a ready-made set-up designed for students to tinker with and perform measurements safely.

Next, Robert A. Millikan, the 1923 Nobel physics prize winner, giving a lecture on his discoveries, including measuring the charge of electrons.

Millikan's apparatus allowed him to carefully measure the exact amount of charge on an electron, using a microscope to track the motion of tiny oil droplets that are attracted to electrically charged plates. Interestingly, this experimental set-up is the basis for photocopiers, where tiny toner particles are attracted to electrically charged plates that transferred onto paper sheets. So when students are recreating Millikan's experiment, they are also experiencing hands-on the principles of early photocopier technology. Again, it would be impractical for students to build a photocopier from scratch in order to measure the charge of electrons, so it is necessary to purchase a ready-made set-up designed for students to tinker with and perform measurements safely.

Here we have Max Planck (1918 Nobel physics prize winner) together with Albert Einstein (1921 Nobel physics prize winner). While they each have a long list of contributions to modern physics, together Planck and Einstein are associated with the fundamental quantum mechanical nature of light.

The apparatus required to do this entails shining low-intensity light of different wavelengths onto the electrons on clean metal surfaces. If the intensity of light is low enough, the light hits the metal surface as individual photons, and these photons can release electrons off of the surface if they have a sufficient amount of energy. Notably, the principles of this experimental set-up is used in many devices such as night vision goggles, where the interactions between individual photons and electrons are used to record images in extremely low-light conditions. So when students are recreating this experiment, they are also experiencing hands-on the principles of night-vision goggles and other similar imaging devices. Yet again, it would be impractical for students to build a night-vision viewer from scratch in order to discover the photon nature of light, so it is necessary to purchase a ready-made set-up designed for students to tinker with and perform measurements safely.

Third and last, how much will this cost, and how many experimental set-ups are needed?

The original grant proposal requests a sum of $30,000 in order to purchase modern physics laboratory equipment that would support the current Physics 208C curriculum. As we have seen, a lower-end cost for each experimental set-up is $800-$1,000. At the minimally reduced funding level, $10,000-$12,000 would purchase twelve key modern physics set-ups. Yet with an enrollment of 24-30 students, each week in laboratory there would be 8-10 groups of students sharing a single experimental set-up. This can be done if student groups use the equipment in rotation along with other tasks during instruction, but this means that each group would only have a few minutes to use the equipment, instead of being able to individually build up, tinker with, and fine-tune their experimental set-ups. Twice this minimal funding level would allow two experimental set-ups for the students to use each week (increasing throughput 200%!), and the full grant request of $30,000 would allow three experimental set-ups to be shared among the 8-10 groups. Thus we request the full $30,000 in order to maximize the educational benefit to these students, giving them as much exposure to these important modern physics discoveries.

Also safety...

...and durability of equipment would obviously be taken into consideration during purchasing, as these experiments are to be a substantive investment in the educational experience of Cuesta College students for many years to come.

Questions or comments?

Thank you for this opportunity to address the Foundation on funding the purchase of equipment for the new modern physics laboratory component to Physics 208C.

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