Making and keeping changes

📘 connect to physics
⚠️ known tripwires
💁🏽 teaching notes

Use the responses to the hinge question to guide children to one of three levels of discussion.

👣 How could you work out whether it costs more to heat a room or keep it warm? 👣

🩺 Children appreciate the different demands for creating changes and maintaining a difference, but may need support to reason about this difference in demand.

Heat a room up and surely it stays hot?

if it's colder outside it'll cost more to warm.

if it's colder outside it'll cool faster, so you'll have to keep warming it up more.

🔎 Start diagnostic and exploratory discussions using thoughts like these:

Try it out, and compare the sizes of the cost boxes.

Insulate the room better, and the cost of keeping it warm will be less. Will the cost of warming it up?

It's just like warming soup and then keeping soup warm.

🩺 Children being argue about the reasons for different demands for creating changes and separate these from the demand for maintaining a difference, where that is necessary. They may struggle to articulate why some changes require maintaining whilst others do not.

Surely it depends how long you keep it warm?

Just like a hot drink — keep it warm for longer by insulating it.

The colder it is outside the more it costs.

🔎 Start diagnostic and exploratory discussions using thoughts like these::

how much do we want to warm it? How much is there to be warmed?

How can the room cool down? Can we stop any of these ways?

I think it matters how cold it is outside.

🩺 Children argue with confidence about the different demands for creating changes and separate these from the demand for maintaining a difference, where that is necessary. They may begin to explore why some changes require maintaining whilst others do not.

You need to know how much you're warming it up and how long you want to keep it warmer.

To make it warmer than a colder outside will cost more, but so will keeping it warmer.

How we'll is the room insulated? Can we stop it cooling down?

🔎 Start diagnostic and exploratory discussions using thoughts like these::

Find out how big the room is and how much you want to increase the temperature.

Find out how well the room is insulated. The better the insulation, the slower it cools after you warm it.

Other changes cost to make a change, and cost again to keep a change. Two different cost boxes.