1Hi Jake.
2How are you getting on with the practical teaching?
3Ah... it's harder than I expected, but I've got some great classes.
4How about you?
5Not brilliant.
6I'm really struggling with my Year 12 science class.
7Are they hard to control?
8Well, I don't have discipline problems as such.
9It's just that they don't seem to think that science has anything to do with their lives.
10It's depressing.
11They listen to what I say,
12and I gave them a test last week and the results weren't too bad,
13but there's no real engagement.
14Right.
15And as part of my teaching practice, I have to design an experiment for them to do.
16I was wondering about something on the children's diets...
17You know, asking them to record what they eat and maybe linking it to their state of health.
18Mmm. Let's think.
19So your methodology would involve the children recording what they eat.
20Okay, but you'd also need to have access to the children's medical records
21and I don't think people would be happy about that;
22confidentiality would be an issue.
23If you could get the right data, the conclusions might be significant,
24but I suspect it's not going to be easy.
25Right.
26Have you thought about doing an experiment using animals?
27Wouldn't that be upsetting for the children?
28Well, the animals don't have to be harmed in any way.
29It could just be an experiment where they're given a certain diet and the effects are observed.
30Would I have to get permission to use animals?
31Yes, you'd have to submit an outline of the experiment and fill in a form,
32but it's quite straightforward.
33But if we found out that, say, a particular diet affects the health of animals,
34the same thing wouldn't necessarily be true for people, would it?
35No, that's true,
36but the findings for any experiment are going to be limited.
37It's inevitable.
38I suppose so.
39So what animals could I use to investigate the effects of diet?
40Mice?
41Yes.
42You'd need experimental mice - ones that have been specially bred for experiments.
43Okay, so what will your experiment be investigating exactly?
44Well, something to do with nutrition.
45So maybe we could look at food supplements...
46Things like extra iron and extra protein, and their impact on health.
47Mmm. That might be rather broad.
48Maybe just look at the effects of one supplement, like sugar, on the health of the mice?
49In fact, maybe the focus could be on whether mice can control their own diet.
50So, what happens when they have access to more sugar that they don't really need?
51Exactly.
52Do they eat it or do they decide to leave it?
53Great.
54Then later on, you could do a follow-up experiment adding another variable.
55Like, you could give some of the mice the chance to be more active,
56running on a wheel or something,
57and the others just sit around and don't do much.
58Or I could repeat the experiment but change the type of food I provided...
59or use mice with a different genetic structure.
60But I think your idea would be more interesting,
61I might think about that some more.
62So can I talk through a possible procedure for the experiment where mice are given a sugar supplement?
63Sure.
64I did a similar experiment in college actually.
65Great.
66So how many mice would I need?
67I'd say about 12.
68And all young ones, not a mixture of old and young.
69Okay.
70And I'd need two groups of equal sizes, so six in each group.
71And how would I tell them apart?
72I suppose I could put some sort of tag on one group... or just mark them in some way?
73You could use food colouring, that wouldn't hurt them.
74Perfect.
75Then each group would go into a separate cage,
76and one group, let's call them group A, would be the control group.
77So they'd just have ordinary mouse food.
78I suppose you can buy that?
79Yes, it comes in dry pellets.
80And the other group would have the same as the first group,
81but they'd also have the extra sugar.
82Would you just give them straight sugar?
83It might be better to give them something like cereal with it.
84Mmm. Then you'd need to weigh the mice, I should think once a week.
85And you'd need an electronic balance.
86But we can't hold them on the balance, or it'd affect the reading.
87Exactly.
88So you need something called a weighing chamber to stop the mice from running away.
89It sounds complicated, but actually you can just use a plastic box with holes in the top.
90Okay.
91So once we've measured the weight gain of each mouse
92we can work out the average for each group, as well as the standard deviation.
93And then see where we go from there.
94That sounds cool!
95I think the students will enjoy it.
96Yes. One thing...