Physics is an experimental science. The validity of the most beautiful theory must be tested by confrontation with measurements on real physical systems. To do so requires apparatus which does not distort the data, is stable, can be calibrated, and can suppress extraneous signals and/or noise. This lab will introduce you to concepts and equipment used in contemporary experiments to achieve these ends.

The equipment should be used with some care; when in doubt as to characteristics or the possibility of damage, consult the resource notebook or your TA or your Instructor. Primary sources such as manufacturers literature are best. Relying on gurus can be unreliable; few of them are willing to say "I don't know," and many will guess or make up an answer. With primary sources, you become an expert yourself.

The lab equipment is in general electrically safe. That means that voltages are low, and cannot deliver enough current to your body to do harm. The power supplies are current limited which means that when connected to a low resistance, they will not deliver enough power to heat things to dangerous temperatures. When you leave this laboratory and work elsewhere, this will not always be the case. Voltages above 30 volts require care, especially if your skin is wet or coated with perspiration. Take care not to connect yourself to them, and take care so that an accidental contact does not let current traverse your heart. Currents of tens of milliamperes which traverse the heart can be fatal because they cause ventricular fibrillation, a rapid weak beating of the heart which pumps little blood. Low voltages with low source impedance (Thevenin impedance) such as automobile batteries can deliver hundreds of amperes and can heat metal finger rings and watch bands to incandescence, causing severe burns. Prudent mechanics disconnect car batteries before working under the hood.

The outside door to WLH2120 should remain closed and locked. An alarm with a delay followed by an ever increasing irritating sound is there to remind you if this is forgotten. Do not attempt to disable the alarm. It is there because of past incidents in which a lab door has been left unlocked, resulting in vandalism or theft of equipment. Without working equipment, it is the end of Physics 120B for the quarter or longer.

Keys for lab access outside normal weekday working hours can be checked out from Earl Dolnick or Tom Parks to a pair of lab partners. They are to be returned the following weekday working day. You are not to work alone because of the chance of accident.

Have fun, be safe, and learn as much as you can about experimental science!