Demonstration of Virtual Lab

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Demonstration of Virtual Lab


This is a transcript of a QuickTime movie (16.5 MB) recorded at the Macquarie ICT Innovations Centre in 2006 when Carol Oliver, from the Australian Centre for Astrobiology, demonstrated one of the virtual field trip tools, Virtual Lab, for high school students.

Transcript:

The first thing you want to do, absolutely, is maximise the window. The best way to use this scanning electron microscope, SEM, as it’s called, is that way. Now what I’m going to show you next, up until recently scientists themselves could not do. What happens is they go to an SEM, that’s a very large instrument about half the size of this room and they sit at a monitor and what you’re about to see is what they see at that monitor. But they can’t take the monitor or the picture or the image away with them in any other way other than a tiff file and they then make a movie from that and that’s the way they look at their sample when they go back to their desktops. Now they can take the SEM to their desktops and so can you. You have an SEM on your desktop.

There is another image on there and it says EDS beside it. EDS means, actually it should be XEDS, it’s from x-ray electron dispersion spectrometer, very long words to explain a very simple concept of using x-rays in the same way as electrons to bounce off the sample and tell us what elements are on the surface of that sample or whatever part of that sample that you’re looking at. And we’ll get to that in a moment.

But first of all I want to show you the sample stromatolite that we used. You can see this one, we’re looking at millimetres, you could even obviously see this. There’s the scale up there and we can see the sample size. Stretch it out across there. You’re looking at seventy-five millimetres, okay? To get rid of that, just click on it, click your delete key, it’s gone, all right? On this one if you really wanted just to try it out, and maybe it’s a good idea, your familiarity with these tools on the right hand side and you could try all of them. Don’t worry about breaking it, you won’t. If you find you do something odd, just go back and relaunch the whole thing. Here you can go up as many as sixty times, okay, and we move around the sample like that. But it’s not very clear, is it? So you just use the focus here, just as you would on an SEM until you get it to how you want it. We’ll move up to here, okay, all right? And there are all sorts of tools here as I said that you can just explore with what you want, all right, okay? Any questions about that before I move on to the next bit because I want you to be able to do this by yourselves? All right, you’re all with me? So we’ll unload that one.

Now I want you to explore the pond scum and the stromatolite, in fact all four images, but I’m just going to show you this one for now. It just takes a moment to load because these are research grade, the image. Now in this university we can’t actually do this here. If we wanted to get images in this format, we actually have to send the sample to the University of Illinois to get it done. So we don’t actually have the facilities to do that and we’re not sure if any university here in Australia has the facilities to do this kind of imaging. So you’ll see across a part of the sample, in fact the sample’s been turned on its side like that and you can see across the layering there, this, you’ll see all this bunch of colouring here. And actually this is where the gold has been put across and the x-rays have been bombarded in this very thin strip. So you can navigate around this. First of all we’ll turn the magnification up. I suggest you start off applying it at a hundred and twenty-five and then you can navigate either this way by just holding the left hand side of your mouse down or you can navigate this way up here by just clicking around. And I’m actually looking for something like that. I’ll explain why in a moment. Now there are lots of different colours in this sample here. Now here are the elements that are described in that sample. It’s actually the sample itself which is telling us which elements are there. Pick one. The person who made this image didn’t say that’s what, you know I’m choosing those ones. It’s the sample that’s saying this is what’s there. So we’ve got aluminium, barium, now barium is very important, that’s why I was looking for the yellow colouration. Barium is something that you find in association with hydrothermal vents. That’s the stuff by those volcanoes that I showed in the beginning with the presentation, okay? It’s a different way of finding the stromatolites near hot springs near volcanoes, okay? So seeing barium there will tell us that that actually came from a hot spring. We’ve got silicon and oxygen as well. So there are also two ways you can tackle this. You can pick out your colours as it is right now or you might actually wan to get rid of all the other elements that are there. First of all just to show you what’s underneath, the opacity you can take right down to the beginning. You can see there is the sample underneath, okay? Look up here, we’re down into microns. We’re at eighty-five microns there but if I take this down, you see we can get well below. Now we are looking at six microns, well, well, well below the width of a human hair. That gives you an idea of the scale there. All right let’s put the opacity back up and I’m going to choose to get rid of the other colours. So I’m going to get rid of the red one, aluminium. I’ll get rid of oxygen. I’m going to get rid of silicon and I’m going to get rid of the iron. So we’re only left with yellow. You might think, hmm that means there’s an awful lot of barium. Well let’s find out if there really is. So you take this little tool here and I’m going to try for a concentration up there. You know you’ve got the tool because you got that little round thing up there. In actual fact, if you look at it you’ll see here’s barium down in here. It’s very low, okay? Maybe we just had a little bit of bad luck there so we’ll go and have a look at another area and we’ll go down in here, say. Well what do we see again? See right off in the corner here, it’s really, really low, all right? Let’s try one more time. Maybe I just really got unlucky, okay? So we’ll go down in here, say, and the same kind of thing. You can bring all of these up and put them wherever you want like this. So we’ve got PO, P1 to go with this one here and right around here. PO is with this sample here, you see it’s right down in there and P2 is down there somewhere, right down the bottom. If you wanted to look at those in more detail, what you have to do is just maximise the window and you can see really how low barium is down in this corner here, all right, so you can get a real read out of it compared to the other elements at that point. And at that point when you’re looking at that sample you then might want to bring in these to see what it looks like, okay, all right? So you’ll see a lot of other tools down the side there that you can explore.

Contents


Introduction

Context

Early Life

Evidence

Acknowledgements

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