Representations

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Representations

Smart Phone Mirror

Students’ ability to visualise the molecules in free space is limited sometimes. So a strategy is to ask the students to take out their smart phone and use it as a mirror by putting it opposite the molecule on the paper, so that they can see the reflection and easily visualise the molecule. This is good for teaching enantiomers and rotating the molecule.

Models to Explain Symmetry

Utilise model making to display principles of symmetry. Make the model, show the NMR spectrum and use them together to explain the symmetry.

Treat Mechanisms as 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.

Demonstrate Reactions

Use a lot of demonstrations - actually doing reactions at the front of the class. You can't actually see the electrons moving when you're doing the reaction, but still it helps to use demonstrations. Beware of possible misinterpretations that could arise when doing demonstrations. 

Link to Article on Effective Use of Demonstrations

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.

Models to Demonstrate Core Mechanism

Use model kits for third year pericyclic reactions: It's visual and it's used every lesson because everything uses the same rule. That's the message to get to them - that you’re not teaching four new things. It's all the same rules. They just move slightly differently. So they see the same models and they can see where the cyclic reactions close. That's very hard to demonstrate in two dimensions. The bigger models are much better as well.

Cartoons

Use little cartoons to show different representations of functional groups, but point out that they are not the reality.

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?

Makeshift Models

Tell them to go to Spotlight and get some toothpicks and some polystyrene balls. The problem then is you don’t have the correct angles, but usually it’s enough to get it out of their head.

Emphasize Reason For Multiple Models

We do Lewis Structures and then we do molecular orbital theory, and it's theory after theory and they say, 'Why do we have to do this theory and this theory and that theory?' You need to say 'Well, because they're all slightly different interpretations because we don't actually know how it is. This is model one and this is model two.'

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