Science

Quantum Dots

This weekend, I was a “mentor” for KEYs, a program to introduce middle school girls to science and engineering. One of the things they got to see were quantum dots. While these have many applications, the demonstration was of their different colors.

For the demonstration, the scientists mixed quantum dots with a hydrogel, then put little pieces of the hydrogel in vials of water. The hydrogel was invisible in the water under ordinary light. Then, they had the girls put the vials under UV light, and the quantum dots lit up in different colors. (There were 3 vials, one with red, one orange and one green.)

They also had the girls look at some under a microscope. Then, they could see that individual dots blinked on and off, and that the appearance of a steady light was only because there were many many quantum dots. The girls thought this was pretty cool.

I wished I could have been one of them, and not a mentor, because I didn’t get to see and do everything. I just told them what I do, and then followed the group around and helped them fill out their worksheets. And got really tired and useless at the end of the day.

One thing that concerned me a little, was that the scientists were men. The lab we were has a woman PI, (she was the one who started the program for middle school girls), and some of the more junior members of the lab were women, but much of the time it was men explaining things, because they were the ones who knew most about the subjects. However, I hope that the girls got the impression that women and men are equal, since there were plenty of women around the whole time. I worry, however, that we sabotaged ourselves.

But to come back to the science without regard to feminism, quantum dots are cool. To summarize them, they are called dots because they are very small, and they are called quantum because each dot only emits a certain wavelength of light, due to the quantized diffence between electron energy levels. When the dots are hit by UV light, some of their electrons jump to higher energy levels, using the energy from the light. When the electrons jump back down, they must lose energy in the form of a specific wavelength of light.

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10 Comments

  1. Vera, I don’t think it’s self sabotage to have male scientists. Although it would be nice if you do this more than once to try to have female scientists in a good number of the classes.

  2. Actually, there is a great deal of data that shows who teaches does make a difference-as it also makes a difference to have all white scientists teaching children of color.

    It’s the “people like me can do this, I won’t be a freak” factor.

    In the studies I’ve seen, it primarily increases the effect size of these early interventions–some kids will always get excited and interested, but more will indicate interest or participate in followups if the proportions of presenters are skewed towards their demographic.

  3. bug, I guess that’s not surprising. It’s better to have role models who look like us, to make it easier to envision ourselves in their place.

    Vera, I’d like to hear more about this KEYs program. I’m not familiar with it. Is it an ongoing thing? Is it something at schools around the country? Etc.

  4. KEYs is just at MIT, I think.
    website: http://ideas.mit.edu/~pscadmin/landing.php?id=12
    It’s quite small, too, 20 is a large number of girls to have for one session. The coordinators are grad students, and as far as I can tell, the effort is all volunteer, so it’s a little difficult for it to be larger. However, they do about 6 sessions per year, and it’s not the same 20 girls each time, although they do encourage the girls to come to multiple sessions.

    I mostly just responded to a call for volunteers, showed up and did as instructed. But one reason I volunteered is that I did Expanding your Horizons when I was in middle school.
    website: http://www.expandingyourhorizons.org/
    which has a new logo since I did it.

  5. Oh, I loved Expanding Your Horizons, only I was one of the presenters! I wish I’d had the opportunity to attend one in middle school — I felt like such a weirdo since I was about the only girl I knew who was into science and the boys would only let me so far into their group.

    I’m glad you got to volunteer! I do think its important — I still run into lots of girls who just think they can’t do math, and it drives me nuts. I do think it’s nice to have both men and women. It’s good to have the person you can identify with at the front of the room, but I also think it’s a good idea to make clear that you’re good enough to play with the boys.

  6. One thing that concerned me a little, was that the scientists were men.

    In the midst of this exciting and rare opputunity, that seems a rather petty concern. I’d be more focused on the fact that a huge majority of the human race will never even have the luxury of witnessing such a thing. Yeah, Carla Sagan would have been incredibly cool, but I’m OK with Carl.

    Just sayin’

  7. More women teachers and more teachers of colour would be ideal, of course – but good science edumacation of any flavour provided to more kids of all kinds is unambiguously good.

    Unambiguous, I tell you!

  8. Vera,

    “One thing that concerned me a little, was that the scientists were men. ”

    I agree. I am an engineer, and a male. One of the really stand out things about engineering, from the university level all the way through into all levels of the profession, is the scarcity of women.

    To speak to this simply. I want more women in industry.

    Some of the smartest, most capable people I went to university with were women, some of the best research I saw when I was working on my short stint in research was by women, and some of the most intelligent questions about my field have come to me from women. So I’ll say right now that anyone who thinks women can’t perform in the sciences is full of it, (and I’ll say that not only to men, but to women who insist that they “just can’t do maths or science”).

    None of this is to say that the women I have known in industry were superior to the men. They weren’t. However, they definitely were not, (and are not), inferior either. What has come clear to me over time though is that the women I know in the sciences bring a different perspective to the problems.

    The women I have known in the sciences have consistently been drawn to different problems than the men, have consistently seen different angles to the problems than men, and as part of a team they have consistently helped improve the overall quality of the solution presented.

    That is why I want more women in industry. The more ways of looking at the problem I get, the more likely I am to find an optimal solution.

    Unfortunately, bug_girl, kinda hit the problem full on with the issues regarding the norming that takes place as a result of ‘who’ is teaching things. Because there are very few women in engineering and the sciences, very few women tend to think that they can make it in the sciences. The only solution I can think of for this is for programs like the one you just told us about to go out of their way to find more women to present.

    That, and somehow the women already in these fields need to be persuaded to make themselves more positively visible to possible future female scientist and engineers.

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