Mum: You know IKEA has a sale on - although I think that it's going to be coming to an end soon.
A: (Sigh) All my friends look down on IKEA
N: Why? Which friends?
A: Pretty much all of them, as it's beneath them to buy anything from there...especially Chris - he can only buy overly expensive furniture for his new house. He wastes so much money. I'll tell you the latest thing he's done. He's put in underfloor heating in his bathroom!! (Pause, as she waits for the full horror of Chris' latest extravagance to sink in with everyone - which it doesn't).
N: So what's wrong with that?
A: Well, it's...it's just stupid. His bathroom is...(looks around room) about the size of this living room.
Mum: That's pretty big.
N: That's a really large bathroom.
A: Ok...(eyes darting back and forth across room)...I guess it's a little smaller than this room. Maybe from this wall to that wall....anyway, it's large for a bathroom but not that large a room. And he only has underfloor heating in that one room, which because it's small means that it's going to take ages to heat up.
A: Well, he only has it in one room and it's a small room, so obviously it's going to take a while to heat that room up.
N: (Sarcastically)According to which law of physics?
A: (Raising voice) Any law of physics. If you heat a room - heat doesn't just stop in that room - it spreads. So heating the whole house would be better as if you are heating one room, that heat has to travel to heat the rest of the house, so the room would take ages to heat up.
N: No it wouldn't. That doesn't make any sense.
A: Yes it does. Heat doesn't think "I'm going to hang about here." It moves. (Starts flapping arms to illustrate heat making a decision.) And so it takes ages for that room to heat up.
N: The room wouldn't take ages to heat up. It's underfloor heating. It would warm up quickly.
A: No it wouldn't.
Mum: I think it would.
N: Have you ever put a heater into our bathroom? Have you seen what happens? It doesn't start heating up the dining room before that room gets hot.
A: That's because it's a heater. Put a radiator or heater in and it's different. It's not under the floor.
N: WHAT? Surely if it's under the floor that means that it is more likely to heat that room rather than others.
A: No, because it's A..SMALL...ROOM.
N: Exactly. So small spaces take faster to warm than large spaces....
A: (Interrupting) ...No, because the heat will..
N: (Talking over)...What are you talking about? It doesn't make any sense.
A: (Snappily) Don't interrupt me.
N: I think actually you interrupted me when I was talking first.
A: Look, the fact that it's under the floor means that it will spread to the next piece of flooring that doesn't have the heat. (Stretches out arm and wiggles fingers to explain heat travelling through the room)
Dad: ...(Suddenly, finding that it's gone on too long) Have you ever studied Physics?
A: (Indignantly) Yes.
Dad: Well, what kind of physics did you study? What level did you get to and what grade did you get?
A: GCSE and I got an A* actually.
Dad: No wonder they say that the education system is failing.
A: Look, you are all wrong.
Mum: (Completely ignoring the last comment)It's good he put that in. He'll have a lovely warm bathroom.
N: It's a good investment - he'll easily recover the cost of it when he sells his house on.
A: (Quietly, almost muttering to herself) Well I think it's a ridiculous waste of energy.