Designing a Mouse Diet Experiment in the Context of Science Teaching
ANNOUNCER: Part 3. You will hear a trainee science teacher called Clare talking about her practical teaching work to another trainee called Jake. First, you have some time to look at questions 21 to 25. Now listen carefully and answer questions 21 to 25.
CLARE: Hi, Jake. How are you getting on with the practical teaching?
JAKE: Oh, it's harder than I expected, but I've got some great classes. How about you?
CLARE: Not brilliant. I'm really struggling with my Year 12 science class.
JAKE: Hmm. Are they hard to control?
CLARE: Well, I don't have discipline problems as such. It's just that they don't seem to think that science has anything to do with their lives. It's depressing.
CLARE: They listen to what I say, and I gave them a test last week. The results weren't too bad, but there's no real engagement.
JAKE: Right.
CLARE: And as part of my teaching practice, I have to design an experiment for them to do.
CLARE: I was thinking about something related to children's diets, maybe asking them to record what they eat and linking it to their health.
JAKE: Hmm. That could be difficult. You would need access to medical records, and that could cause confidentiality issues.
JAKE: Even if the results were interesting, getting that kind of data would probably be hard.
CLARE: Right.
JAKE: Have you thought about doing an experiment using animals?
CLARE: Wouldn't that upset the students?
JAKE: Not necessarily. The animals wouldn't need to be harmed. You could simply observe how different diets affect them.
CLARE: Would I need permission?
JAKE: Yes, you'd have to submit an experiment outline and complete a form. But it's straightforward.
CLARE: But if a certain diet affects animals, that doesn't necessarily mean the same thing happens to humans.
JAKE: That's true. But every experiment has limitations.
CLARE: I suppose so. Maybe I could study the effect of nutrition on animals.
CLARE: For example, looking at food supplements like extra iron or protein.
JAKE: That might be too broad. Perhaps focus on one supplement, such as sugar.
CLARE: That's interesting. Maybe we could see whether mice control their own diet.
JAKE: Meaning if they have access to more sugar than they need, will they eat it anyway?
CLARE: Exactly. Or will they decide not to eat it?
JAKE: Later you could extend the experiment by adding another variable.
JAKE: For example, letting some mice exercise on a running wheel while others remain inactive.
CLARE: Or repeat the experiment using different food or mice with different genetic structures.
CLARE: But I like your idea. I might develop it further.
ANNOUNCER: Before you hear the rest of the discussion, you have some time to look at questions 26 to 30. Now listen and answer questions 26 to 30.
CLARE: So, can I talk through the procedure for the experiment using mice and sugar?
JAKE: Sure. I did something similar at college.
CLARE: Great. How many mice would I need?
JAKE: About 12 mice, and they should all be young.
CLARE: So I'd divide them into two groups of six.
CLARE: I could mark one group with food colouring so I can tell them apart.
JAKE: Yes, that wouldn't harm them.
CLARE: Then each group goes into a separate cage.
CLARE: The first group would be the control group and eat normal mouse food pellets.
CLARE: The second group would eat the same food but also receive extra sugar.
JAKE: Maybe you could mix the sugar with cereal.
CLARE: Good idea. Then I would weigh the mice weekly.
JAKE: You'd need an electronic balance.
CLARE: But we can't hold them while weighing them.
JAKE: That's why you use a weighing chamber.
JAKE: It can simply be a plastic box with holes so the mice don't escape.
CLARE: After measuring the weight gain of each mouse, we can calculate the average and the standard deviation.
CLARE: Then we can analyse the results.
JAKE: Sounds good. I think the students will enjoy it.
ANNOUNCER: That is the end of Part 3. You now have 30 seconds to check your answers to Part 3.