1. A century ago, watches and clocks were made using a system of interlocking gears. Explain why the rotation of those gears might tell time. How might the size of those gears affect a clock’s accuracy?
2. The world’s atomic clocks have a precision most people cannot wrap their heads around. Can you envision why that level of accuracy would be helpful to cell-phone systems or the electric power grid?
1. How many years would have to go by before the newest atomic clock might lose or gain one second of time?
2. Why is it a bit wrong to call F2 a “clock.”
3. Which NIST clocks — and how many of them — are used to tell the official time of day?
4. How many times each day do computers and other network devices ask NIST for help in synchronizing their time?
5. The heart of the new F2 device is a pool of what?
6. What creates optical molasses inside F2?
7. In what year did NIST scientists pioneer laser cooling?
8. What happens when microwave energy gets picked up by cesium electrons?
9. F2 is a cesium atomic clock. What will the next generation of atomic clocks be called? And how much better than cesium clocks are they predicted to be?
1. NIST was developed to create the most accurate and reliable measurement standards. Name two types of these “yardsticks” — that is, measurement systems — that might need a continual upgrade in accuracy, much as timekeeping has?
2. Find five people wearing a watch with second hands. Set your clocks to the same precise time. Now chart their time at some point every day for a week when you are all together. Then do it for one day every week for a month, again when you are all together. Who had the fastest and who had the slowest time? How much faster were they from the average time for all five watches? Under what types of situations could your watch being off by a difference of seconds to minutes make a difference in your life? Where would you go to find the most accurate time?
1. Create a timeline of the changes in time measurement over the centuries. Describe how each type of “clock” measured time. (One source to get you started: http://www.time-for-time.com/clocks.htm)
2. Create a map of the world’s time zones. Why are these needed and how were they developed?
3. Explain daylight savings time. What is its history and why is it important to businesses and farmers? What kind of safety issues sometimes arise when people do or don’t adopt daylight savings time?
J. Raloff. “World’s coolest ‘clock’ is also crazy-accurate.” Science News for Students. April 16, 2014.