Analogies and Metaphors

Coffee/Iceberg Analogy

Which has a higher internal energy - a 'nearly boiling' hot cup of coffee or an iceberg? This is the ‘q vs T paradox’. The mass of the iceberg is greater so it has a higher internal energy despite being colder. Ask students to explain what happens when you place the cup of coffee onto the surface of the iceberg – why doesn’t heat flow from the iceberg to the coffee to make it boil? The discussion of why heat dissipates from hot to cold is useful in reinforcing the role of entropy.

Macroscopic Size Analogies

I find that some students pick up what the mole concept is from the idea of grouping numbers of things that are every day size. 

Curly Arrow Cartoons

The actual curly arrow mechanisms are in a way themselves cartoons, how they map to the reality in the way that a Micky Mouse might map to real life.

Population Analogy

Use the analogy of populations migrating between adjacent cities.

Electron Auction Analogy

When talking about curly arrows and electrons moving, talk about reactions as a trading port for electrons - electron auction - in terms of trying to understand who has got electrons and who wants them.

Hands Analogy

Get students to recognise the importance of functional groups: Start with hydrocarbons, and talk about skeletal structure and say we can ignore the hydrogens, they are kind of like your skin, but the functional groups are the things that do things, so they’re your hands. The functional groups will actually do things with other compounds. Then slowly introduce the concept that most compounds have two or more functional groups, and then you have competition - which one will react first?

Ball on Steps Analogy

An analogy in quantisation of energy states takes advantage of the fact that in many lecture theatres there are shallow steps going down to the front. Think of a ball rolling down the steps. It can't stop halfway down the steps. It seems like a really simplistic way of thinking of it, but in terms of analogy it works really well.

Kid's Rooms Analogy

An analogy for talking about Hund’s rule (where the p orbitals fill up) is that it’s like parents deciding where siblings will sleep. If you have enough rooms you put each person in one room because that's peaceful for everybody and everybody prefers that. If you have an extra child you have a choice of renovating your house, which is expensive and takes a lot of energy, or you put them in the same bedroom. You are going to put them in the same bedroom because you're not going to renovate your house. They get that.

Bus Analogy

In hybridisation, we have the idea that the energy at the atomic levels are changing - they're not going to be the same as an isolated atom on its own. Think about if you were sitting next to someone on the bus. You would sit there differently than if you were sitting there alone. If you're the only person on the bus and then somebody else gets on the bus, how would you feel if they came and sat right next to you? We know instinctively they wouldn't do that. Electrons are a bit the same. They won't sit in the same spot. Once all the seats have someone in them then they’ll sit next to you.

Orbital Analogies

Use an analogy for filling orbitals, such as climbing up a ladder or building a house from the bottom up.


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