PHYSICS I - HONORS P ROBLEM OF THE WEEK W HAT IS P HYSICS ? Time The length of a second is a human convention. In 1820, a second was defined as 1/ of a day. The logic being that Here at the turn of the millenium, the length of one second is defined as the time it takes for oscillations of the radiation emitted/absorbed by the atoms of cesium-133. When talking about clocks, accuracy is the name of the game. C LOCK To measure time, you need a clock. Most of us carry around compact quartz clocks on our wrist. Suppose that your wrist clock lost or gained one second every thousand seconds. Then your time would be off by 43 minutes in one month. Sample Calculation: Nm = number of seconds in one month PROBLEM 1 A good quartz watch is accurate to the millionth of a second. In one year, how far off would this watch be? Use scientific notation and the factor- label method in your calculations. NIST - 7 The clockmakers at the National Institute of Standards and Technology in Boulder, Colorado would like to offer you a clock, maybe for your hallway. The clock, called the NIST-7, will cost you $50 000, but you will get a clock that is accurate to the fourteenth decimal place. PROBLEM 2 How old will you be when you need to call the NIST people to report that your clock is off by one second? NIST-7 uses oscillations of radiation that are emitted by cesium-133 to keep time. When the clock is one second off, how many oscillations will have occurred? Use scientific notation and the factor- label method in your calculations.