Use the responses to the hinge question to guide children to one of three levels of discussion.
👣 How could you work out what costs most to run while switched on? 👣
🩺 Children focus on one salient feature, perhaps shown by talking like this:
The hotter things will cost more.
The brightest things will cost most.
The smaller the thing is, the less it will cost.
🔎 Start diagnostic and exploratory discussions using thoughts like these:
The hottest things cost most. The toaster and stove top glow.
What about the brightness? Very bright lights must be very powerful.
Big radiators might not be hot, but they warm the room a lot because they're big. So they might not be the hottest or brightest, but still cost more when running.
🩺 Children consider multiple qualitative features in judging the power demand, eg brightness, hotness, time to warm a fixed mass or volume. Children thinking along these lines might use talk like this:
The size of the cooker ring and the number you turn it up to set the cost.
The brightness of the TV screen and its size tell you about the cost.
🔎 Start diagnostic and exploratory discussions using thoughts like these::
Big cooker rings cost more when running than small rings.
Surely it depends how much you turn the rings up? Setting them on a big number heats things up faster.
What about how full the pan on the ring is? Won't that affect how much it costs when running?
