Physics is...

Questions answered by Gesine Grosche, PTB Working Group "Unit of Length".

1. What were your reasons for studying physics? During my studies of mathematics and natural sciences, I became aware that my way of thinking was most similar to that of physicists. Not the subjects treated or the problems were decisive, but the methods.
2. What university did you go to? Cambridge and London.
3. Did you know a physical experiment at school which particularly impressed you? What are the physical experiments which impress you? Coupled pendula
4. Your physical aha-experience? Statistical mechanics – a little of quantum mechanics and some counting: and yet you can calculate things like heat capacity which can be determined by macroscopy.
5. Do you have a favourite experiment? Confirmation of Archimedes’ principle by experiments on one’s own body (in water).
6. Are you also interested in a completely different speciality? Etymology / linguistics
7. What profession did you aim for as a child? Philosopher
8. Have you ever had a chemical kit? Yes!
9. By what do you recognize a physicist? I hope by the insatiable desire to question things, to get at the root of things.
10. Your recommendation for future students of physics? Don’t let rigid structures get you down. Physics should be fun.
11. Do correct measurements require a healthy amount of ambition? No – only understanding and patience. “Incorrect” measurements per definitionem are of no worth.
12. Those who measure a lot, measure a lot of rubbish... Do you think this saying contains a grain of truth? Only those who have measured a lot of rubbish will learn how to measure what’s important with few measurements.
13. Do you understand quantum mechanics? What do you understand by “understand”? We understand hardly anything. But if “understand” means: being able to predict new observations on the basis of a model, then quantum mechanics is nothing special. One has to accept certain things. Then the consequences can be “understood” without difficulty. By the way: Just quantum mechanics has effects which can be directly recognized in a great many experiments. Quantum mechanics has, for example, become “touchable” in optics and solid-state physics.
14. What are light quanta? Phenomena which exhibit certain characteristics such as proportionality between energy and frequency with h as the proportionality factor.
15. A trip to the moon – would you like it? Yes, at once (over the weekend).
16. Your favourite measuring instrument? A detection map for IR radiation! Extremely reliable and not calibratable.
17. Do you master a musical instrument? Let’s say my piano is mastering me.
18. What measuring instrument would you least be able to dispense with? At present: the oscilloscope
19. What measuring instrument is in your opinion useless? Can a tool which has been deliberately created really be superfluous? Some instruments may have become obsolete.
20. Why does the world exist? Because a mouse is looking at it? Why does the mouse exist? Does it exist in order that the world might be looked at and exist? And what if the cat comes?
21. A good measurement is always carried out very carefully, almost ceremoniously. Is this ceremony comparable with a sacred rite? A good measurement is sometimes carried out after 537 poor measurements, at 2.30 h in the morning. Before this rite, there is in most cases hardly any time for ablutions.
22. What is in your opinion most important in a measurement? The model assumption and the readiness to accept deviating observations
23. Correct measurement – a mechanical art or a science? Mechanical art, habits and experience
24. Would you tell us three important events of your biography? Birth. The discovery of the tininess of human existence during the first deliberate flight in a sailglider at the age of 4 (as a passenger, to avoid misunderstandings!). Discovery of ignorance some years later.
25. Do you think there are things which cannot be measured? In the affirmative, what? Only a few things can be measured.
26. Did you ever see the primary kilogram in Paris? Unfortunately not
27. As you know, the Internet was invented by physicists to communicate in virtual terms. Would you have liked to be among the team of the “first Internet hour?” No. Before there were the amateur radio and similar things – what is so special about the Internet is its simplicity and global use.
28. Which physicist do you admire? Above all those who continue their work under extremely difficult conditions
29. Complete the sentence: “A life without measurements is... monotonous.”
31. Do you remember the most important measurement of your life? Yes
32. There was a time when certain physical experiments were suddenly regarded as politically undesired. How political can physics be in your opinion? Physics is unpolitical, but extremely important to politics
33. Is it possible to still discover something new in the field of physics? Simply thought: in quantum mechanics we have the physics of small scales. What do we know about physics of extremely short times?
34. Is nature really as physics, biology and chemistry describe it? Tautological question. Our description explains more or less what nature can be for human beings. So what we call nature is as it is.
35. Try to find a definition for coincidence. Coincidence is necessary.