For any idea, it’s important to see both the details and the big picture. There are loads of different ways to get you thinking about this, from de Bono’s Thinking Hats to applying Bloom’s Taxonomy. This is another, and works well for thinking through an idea in lessons, reviewing work or as part of revision. You can scribble it quickly or use the printable version below to record it for the future.
What is the main idea? Sum it up in a sentence, a definition, or an equation.
Thermal radiation: heat can be transferred as an EM wave
How does it fit into the world or the universe? Why does it matter? What are the most closely related ideas?
Like other kids of heat transfer (conduction and convection) it is caused by a difference in temperature.
What key words or relevant characteristics will suggest this concept is important? What will need to be considered to explain it? What words in a question will give a clue that this idea is related to the answer?
The colour and surface area of the object affects how quickly heat is emitted or absorbed. Heat can be radiated through a vacuum. It is also called infra-red (IR) radiation.
How does it work? What makes it happen? Does this mean it can be predicted, or prevented?
Heat is transferred along a temperature gradient. Bigger differences mean heat is emitted faster (higher power). Shiny surfaces reflect thermal radiation.
What effects does this have? Is it dangerous? Does it have implications for spending or earning money? How is it used in technology?
We can’t stop it, only slow it down. We use shiny or polished surfaces to reduce it, for example in Thermos flasks. An object will cool faster if it is a dark colour with a large surface area, so we include cooling fins on electrical equipment like laptops, fridges and freezers. Ear size in animals tells us about the climate they live in (compare arctic foxes with elephants). As the ice caps melt there is less reflection of thermal radiation to space, possibly accelerating climate change.
If you can explain the different aspects of an idea like this, then you probably understand it well enough to use in a variety of situations. And that, after all, is the point of learning.