Playing CSI

[ffutures]

Every year the school where I work runs a two-day event to encourage year 9 kids (14-ish) to take up a career in science. The final part of it is a big forensic science investigation where they use some clues to find out who committed a murder. This involves testing fabrics to identify the material, chromatography of ink samples, testing chemicals, working out the height that blood drops have fallen from by measuring the diamater of the splatter, testing coffee for sugar, analysing a floppy containing suspect data, fingerprinting, and so forth. The investigation takes most of the morning, then they have to present the results and accuse the "guilty" teacher in the afternoon.

One of the things we've done the last couple of years is have them extract DNA from blood (actually pureed kiwi fruit with dye). When they give me a tube with the DNA in it (it looks like wooly fibres) I put a sample on a slide and put it into the "official DNA tester" then give them a "printout" of the suspect's DNA test, which is compared to results for all the teachers. The snag is that the "Official DNA tester" dosn't work - a real DNA analysis secup costs a couple of hundred thousand and takes a couple of days. So it needs to be a convincing fake.

The first year I used a data-logger of a type that they weren't familiar with and put one of the sensors over the slide and pretended it was doing something. Not very convincing.

This year I put the slide onto the stage of an Intelplay microscope (basically a webcam with microscope lenses), let them see the fibres on the window of an image capture program, then scrolled down the actual image that had already been prepared to show a representation of a DNA molecule before giving them the printout. Pretty, but it was a bit obvious what I was doing.

What I really need next time round is some sort of app (maybe just a prepared web page) that will show the camera input on one side and has some impressive-looking buttons which, when pressed, give the appearance of zooming in to the DNA and analysing it on an image below the first. This could be something as simple as an animated GIF. It doesn't necessarily need to print out since that bit will probably still be faked, but that could be a possibility.

Any suggestions on how to do this, remembering that I'm not exactly the best programmer or web designer in the world?

Question for Australian readers etc.: One of the experiments, taken from an Australian web site, was supposed to use "corn syrup" to make the perfect blood spatter mix. Snag is that the stuff doesn't seem to be on sale in the UK, can anyone tell me what this is in British terms? The stuff we used worked, but not as well as we would have liked.

Comments

[scimon.livejournal.com]

Shouldn't be too hard to run something up with javascript and som prepared images.
You could have it that they can click on areas of the 'DNA' image to zoom in on that section.
When do you need it for?

[ffutures.livejournal.com]

It'll be this time next year - but with regards to some of the othercomments, maybe I shouldn't aim too hard for authenticity. They won't be able to spend a lot of time at the computer anyway, since it's the ancient one I use - all of the other computers in the lab are needed for the data analysis thing.

[maviscruet.livejournal.com]

Don't have any useful advice, other then to say that does sound pretty cool.....

Rigged demo = Bad Science

[akicif.livejournal.com]

It may all be in fun, but I'd honestly say that having any scent of fakery would detract horrendously from the rest of the event.

And that's without going into the area of having kids growing up thinking DNA testing is quick, cheap and easy....

Corn syrup's a hydrolysis product of maize, so presumably glucose plus oligomers - a sugar solution of similar specific gravity (http://www.csgnetwork.com/sgvisc.html) might serve as a starting point, or there's more details here.

Re: Rigged demo = Bad Science

[karohemd.livejournal.com]

I agree that faking it is a bit off, at least without telling them.

Why not explain it?
"DNA analysis would cost hundreds of thousands of pounds which our poor school can't afford but if you were to test the DNA, it would look something like this?"

Re corn syrup, I believe I read somewhere that proper film/theatrical blood uses that recipe, maybe you can find a supplier?

Re: Rigged demo = Bad Science

[ffutures.livejournal.com]

Oh, the kids would have to be pretty dense not to realise that the experiments are rigged - they have to do everything in about two hours so we give them things like a suspect ink sample that is a cartridge full of ink, not a microscopic quantity that has to be removed from writing paper, a cloth sample that's about 1 x 15 cm instead of a single thread, "blood" that is fairly obviously pulped fruit with dye, a murder weapon that's a plastic butter knife, and so on.

Maybe I didn't explain it well; I don't want to con them, it's more a case of stage dressing to make it more fun. For example, for my "DNA analyser" this year the microscope still had the Intelplay logo visible and the computer was labelled "DNA Analyser" with a sticky label. I also make it clear that I'm giving them a prepared result, not the actual analysis of their specimen.

Re: Rigged demo = Bad Science

[robertprior.livejournal.com]

Sounds like what you want is an app that acts as a "fast-forward", showing the same steps as a real DNA analyzer would do, but faster.

[pauldrye.livejournal.com]

Corn syrup is used in North America as a cheap substitute for maple syrup for pancakes and the like. It's pretty similar to golden syrup, though a lighter yellow in colour.

[ffutures.livejournal.com]

Okay, well we used golden syrup anyway, maybe I got the strength wrong or something.