• Question: What was your favourite scientific experiment ever?

    Asked by lumiereclair to Mark, Matthew, Mike, Paul, Sabina on 7 Mar 2014.
    • Photo: Mark Jackson

      Mark Jackson answered on 7 Mar 2014:

      I’m going to answer the opposite question: what my most un-favorite scientific experiment ever was.

      In summer 1996 I participated in the Summer Undergraduate Research Fellowship program at Caltech. While living on campus I often encountered flyers soliciting volunteers for local experiments and offering a small compensation. Usually these were psychological experiments, which didn’t interest me very much, but one day I saw an announcement requesting volunteers to determine whether humans could sense magnetic fields. Some animals (pigeons, most famously) apparently sense the earth’s magnetic field and can use this to navigate – did humans have a similar ability, though we were not consciously aware of it? I eagerly volunteered and was accepted.

      The set-up was the following: around me was placed a large metal “birdcage” which could produce a strong magnetic field. To my hands were strapped a sensor measuring my perspiration, and a wire capable of delivering an electric shock. Every few minutes the investigator would magnetize the birdcage, and then a few seconds later shock me. The theory was that after this repeated a few times my body (if it could sense the magnetic field) would correlate the magnetic field with the anticipation of being shocked, and I would therefore sweat, which would be measured by the sensor.

      What actually happened was that I simply sat in a birdcage for an hour being shocked repeatedly, and sweated the whole time. For this I was paid $10. I don’t think humans can sense magnetic fields.

    • Photo: Matthew Malek

      Matthew Malek answered on 7 Mar 2014:

      I probably shouldn’t answer this but, truth be told, it’s the Milgram experiment (http://en.wikipedia.org/wiki/Milgram_experiment). Not in my field at all, and impossible to do today (would never pass an ethics panel), but it tells us important stuff about human nature.

      For similar reasons, I also like the Stanford Prison Experiment (http://en.wikipedia.org/wiki/Stanford_prison_experiment), as shocking as the results are.

      (Did I mention that I used to want to do psychological research?)

      If we’re going back to physics, my favourite experiment is the Super-Kamiokande experiment, on which I did my thesis research. See the first picture on my profile page. It’s just beautiful!

    • Photo: Sabina Hatch

      Sabina Hatch answered on 10 Mar 2014:

      I found this question very hard to answer… I don’t think I have a favourite to be honest. Some are more impressive than others and usually this correlates to the size of the machinery used (e.g. CERN) or huge telescopes. But really it is always the anticipation for me with an experiment, not knowing what will happen, what will I find? It is like a magic trick I guess, once you know how it works/the secret then it is not as impressive anymore. But it is always that first one, when you don’t know what to expect and are amazed buy it!

      I remember one experiment from university where we made holograms of small objects on transparent films using light. I thought that was pretty cool. My favourite thing even now (although it really isn’t an experiment) is to use a scanning electron microscope (SEM) to look at things I’ve made, until I use the SEM I have no idea what the material looks like and you can get some pretty cool images. Sometimes when I was expecting nanowires I made nanotubes by mistake, and some looked like miniature trees. I doubt I will ever get bored of using an SEM to look at things on a really small scale. I would suggest people to google “SEM images” and anything else you can thing of (e.g. insects, sand etc).

    • Photo: Mike Lee

      Mike Lee answered on 10 Mar 2014:

      Voyager space missions, and the pale blue dot. http://www.youtube.com/watch?v=p86BPM1GV8M

    • Photo: Paul Coxon

      Paul Coxon answered on 10 Mar 2014:

      My favourite experiment is the Millkican Oil Drop experiment, done by Robert Millikan in 1909.

      It’s such a simple and staggeringly beautiful experiment that reveals one of the fundamental properties of the electron – the size of its charge.

      Millikan made spray of tiny charged oil droplets and measured how strong an applied electric field had to be in order to stop the droplets from falling. Since he was able to work out the mass of an individual oil drop he could calculate the force of gravity on one drop, he could then determine the electric charge that the drop must have. By controlling the charge on different drops, he noticed that the charge was always a multiple of -1.6 x 10 -19 C, the charge on a single electron.

      This experiment earned him the Nobel Prize, and it’s now taught in practical physics demonstrations in schools throughout the world.

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