Chemistry Discipline Network - Nature of Matter

Molecules are Three Dimensional

bdargaville — Mon, 22 Feb 2016 01:36:49 +0000

It is vitally important for their understanding of chemistry that they understand that molecules are three-dimensional things and that they have a spatial requirement in that they have a shape of their own and that shape will change. They can't do higher level manipulations without an understanding of three-dimensional nature of molecules.

Topic:

Macrocropic vs Microscopic

bdargaville — Thu, 18 Feb 2016 00:59:31 +0000

I think for a lot of people, before they started chemistry, especially if they haven't done any chemistry before, they've got no real understanding of the difference between macroscopic things and microscopic and atomic sized things. We all know how important that distinction is.

Topic:

Strategy:

Representing Energy

bdargaville — Thu, 18 Feb 2016 00:56:56 +0000

When you think of things in terms of energy you can represent energy … energy can be modelled as a particle, as matter. It can be modelled using waves and then trying to talk about how we would use each model as it's appropriate for a particular situation. It's the sort of things we observe might dictate which model we use to explain it, by recognising that in each case there is another model but perhaps just not as useful. So maybe it goes back to just trying to show that everything that we do is a model, every model has its upside and its downside and that we usually only use a model that’s as detailed as it needs to be for the particular concept that you're trying to get across. If you want to get across a concept of a car to someone who has never seen a car you don't probably show them a Ferrari or a drag racing car. Maybe you show them a Lego style block and we do the same thing with our scientific models as well. I guess trying to get across that idea that this is the model that we're going to use but it can be a lot more complicated. I don't want you to think it's as simple as this but it's appropriate under the circumstance. So I guess I spend a lot of time talking about things as models when I'm talking about quantum mechanics. Our treatment in the first year, which is where I cover it, a little bit of second year but I don't take a mathematical detail treatment of quantum mechanics. Someone else does that, so I really bow to them. So most of mine is non-mathematical, just simple mathematics and mainly conceptual type of stuff. I guess some of the things I try and do to illustrate the differences between the models and the way that we use them is to ask questions in class that might be postulated in such a way that you can't answer it if you're thinking about both models at the same time. So the one I like is where I show say a 2s orbital and the probability distribution of that node in between. I talk about things that … there's one briefly, this plum pudding model which they all laugh about. When you look at this 2s model there is a probability and a high probability, relatively so, that the electron can be inside the nucleus, if you think about it in particle terms. Then talk about the nodes and so on and how they arise in quantum mechanics and so on and then ask questions like if the electron can be here and here but it can never be here how does it get there? ... I try and get across maybe the bigger picture, everything we're going to do from this point on (because we do this fairly early in first year) - everything is going to be a model. Nothing is going to be right. Nothing is going to be wrong. Nothing is going to be exactly the way it is. Everything will be just a model. You'll hear us saying things like ‘this is how it is’ or ‘this is what's happening’. But really you need to interpret that as ‘this is a model and this is how this model is used to explain this particular phenomenon.

Topic:

Strategy:

The Basic Structure Of Matter

bdargaville — Thu, 18 Feb 2016 00:46:14 +0000

This understanding builds students' knowledge about the basic structure of matter which stimulates them to think in sub-microscopic level that provides the fundamental understanding for further chemistry learning.

Topic:

Strategy:

Particle-Wave Model

bdargaville — Fri, 12 Feb 2016 03:52:06 +0000

Try to show students that the fundamental form of matter is energy. Then that this can be represented as particles with mass or as waves (wave functions). Then try to show them that we use the model particle/wave that best helps us understand different phenomena. In class I often do this by asking questions about wave mechanics in particle terms. eg. If a 2s orbital has a node how can the electron pass accross it? Then explain to them the limitations and advantages of each approach.

Topic:

Strategy:

Predict-Observe-Explain

bdargaville — Tue, 09 Feb 2016 04:13:44 +0000

Provide students with learning experiences via predict-observe-explain.

Topic:

General Chemistry
Nature of Matter

Strategy:

Active Learning
Student Participation

A Series of Models

bdargaville — Tue, 09 Feb 2016 04:11:50 +0000

Try and get across the bigger picture - everything you're going to do is going to be a model. Nothing is going to be right. Nothing is going to be wrong. Nothing is going to be exactly the way it is. Everything is a series of models.

Topic:

General Chemistry
Nature of Matter

Strategy:

Content Structure
Big Picture Focus
Representations
Models and Representations

Particle-Wave Duality

bdargaville — Tue, 09 Feb 2016 04:01:30 +0000

Try to show students that the fundamental form of matter is energy. Then that this can be represented as particles with mass or as waves (wave functions). Link to YouTube Video: Particles and Waves

Then try to show them that we use the model particle/wave that best helps us understand different phenomena. In class you can do this by asking questions about wave mechanics in particle terms. eg. If a 2s orbital has a node how can the electron pass across it? Then explain to them the limitations and advantages of each approach.

Read a related quote here

Topic:

General Chemistry
Nature of Matter
Physical Chemistry
Quantum Mechanics

Strategy:

Representations
Models and Representations
Technology
Online and e-Resources

Macroscopic Analogies

bdargaville — Tue, 09 Feb 2016 03:38:18 +0000

Students come in, like all of us, trying to apply macroscopic analogies to everything – (the billiard balls colliding and similar things) and using them as models for atoms. Try to get across that it's a simple analogy but it's not as simple as that in reality. I guess go back a step and try and show that everything is really just a form of energy.

Topic:

General Chemistry
Nature of Matter

Strategy:

Representations
Analogies and Metaphors

Compressibility Demonstration

Madeleine Schultz — Fri, 05 Feb 2016 21:36:52 +0000

You can get the students to physically feel that liquids are not compressible by giving them three closed syringes: one contains water, say 50 mL, that’s been put in the freezer to become ice; another syringe contains 50 mL of liquid water, and the other one is gas. Ask them to push the syringes and see what happens. They find they cannot push the syringes containing liquid or solid, even though they think there would be some space in the liquid one. The misconception is that liquids fall somewhere between solid and gas and so should be “a bit” compressible.

Topic:

General Chemistry
Nature of Matter
Physical Chemistry
Intermolecular Forces
Phase Transitions

Strategy:

Active Learning
Lab-Based
Representations
Demonstration and Simulation