Room B-204: Student Laboratory Rules
Any experimental work after 5 p.m. must be booked with Dr. Hsu two days in advance, and no student may stay in the room alone. Broken glass goes into the red box, never into the paper bin.
Dear Professor Yang,
My name is Kevin Chou, and I am a second-year student in chemistry. I heard your talk about clean water last month, and I would like to ask whether your laboratory takes student helpers during the summer.
I spent one term working with Dr. Lin, mostly washing glassware and recording data, so I know how slow real research can be.
I can offer four full days a week from July 1 to August 31. I have attached my grades and a one-page report on a simple experiment I designed myself. If there is no room in your group this year, I would still be grateful for advice on what to read.
Yours sincerely,
Kevin Chou
An atomic clock in a locked room in Colorado loses less than one second in a hundred million years. Few people need that kind of accuracy, yet almost everyone uses it, because every phone map depends on satellites that carry such clocks.
The scientific idea behind them is simple. Atoms of one metal always take exactly the same tiny amount of time to change their state, so counting those changes is more reliable than counting the swings of a pendulum.
Engineers are now building a clock that is ten times more accurate. Their aim is not to be on time for dinner, but to measure how gravity slightly slows time itself.
Two classes repeated the same experiment: they dropped a ball from a height of one meter onto four surfaces and measured how high it bounced.
| Surface | Class A | Class B |
|---|---|---|
| Wood | 62 cm | 58 cm |
| Glass | 71 cm | 74 cm |
| Carpet | 24 cm | 21 cm |
| Sand | 6 cm | 5 cm |
Each figure is the average of ten drops. The two classes used balls of the same weight.