Post Tagged with: "lecture"

A tale of a tired lecture course. Flip it.

It dawned on me that no one cared. The proteins that I found so fascinating just didn’t seem to intrigue them as much as they did me. I thought the video of water molecules flipping as they passed through the channel of aquaporin was marvellous. But it hardly gleaned a reaction from the sea of faces staring blankly out at me. 

Screen Shot 2015-05-19 at 14.42.33

I left the lecture theatre and trudged back to my office. Wondering what was to be done with the course I’d tinkered with for years and never been happy with. Maybe it was time to just stop tinkering, throw it all away and start afresh?

The thought drifted away as I flicked through the, not insignificant, pile of emails that had dropped into my mail box during my brief absence from my desk. Top of the list was request to review a grant proposal.

And then inspiration struck, I could get my students to write grant proposals! That way they could explore the ideas and material that they are interested in without having my predilection for Major Intrinsic Proteins foisted on them.

So I set about a total revamping of the course.

  • The lectures slides went in the bin.

Well actually they got turned into screencasts. But they might as well have gone in the bin, because the students don’t watch them.

  • I gave the students examples of grant proposals that I’d written (ones that had got good reviews, even if they hadn’t been funded 🙁 ).
  • I supplied them with a load of references to papers that contained neat ideas.
  • And I gave a lecture with avenues of research that I thought were intriguing.
  • Then I provided them with a slightly altered version of a research council’s form and told them to complete it i.e they had to write a case for support, lay summary, justification for resources etc.
  • They worked in groups of 6-7 and set about their tasks.
  • The rest of the lectures I turned up to check on how things were going, guide the projects, tell them what I thought might work or not etc.
  • And come the end of the course I marked the proposals based on genuine research council criteria AND each group peer reviewed 3 other proposals using the same criteria. Group members also gave an effort mark to each other (so free loaders didn’t get an easy ride). And the final mark was made up from an amalgamation of my mark, the peer review and the inter-group mark.

The results were great. Some really fabulous ideas sprung up. I’ve had students ask me if they can actually work on their research projects during their final year dissertations, and I bet some of proposals would have made the quality cut off in real funding rounds.

Right, enough from me, I’ve just come across a great idea for a project I need to get into the next funding round. 😉

By May 19, 2015 3 comments chemical education

Great Show But Was the Chemistry Quite Right?

A guest blog post by Dr Nigel Young, an inorganic chemist at the University of Hull.

I have just watched the first of the 2012 RI Christmas Lectures entitled “Air: The Elixir of Life”  by Dr Peter Wothers on BBC4. Whilst there were many excellent demonstrations and explanations (some of which I may make use of) and it is very good to see chemistry portrayed in an enthusiastic manner I am a little concerned about the way that chemical bonding was dealt with which was confusing, and almost certainly incorrect. He had a terrific contraption representing a diatomic molecule, and by adding electrons into a holder between the atoms they got pulled together to represent bonding orbitals. When electrons were put into anti-bonding holders the atoms moved further apart. This all sounds fine, but the alarm bells began to ring  when the consequences of considering that there are both 2s and 2p electrons/orbitals involved in the bonding were ignored, and especially the fact that the bonding and anti-bonding orbitals derived from the 2s set are filled before getting to the 2p ones. The approach used in the programme predicts that Be2 has a considerable bond energy/strength as it has four bonding electrons, whereas experimentally and computationally it is very weakly bound if at all, and this is because it has an equal number of bonding and anti-bonding electrons. It was also stated that C2 has the strongest bond energy, whereas amongst the diatomics this is found for N2. He seemed to show a chart of increasing bond energy/strength from Li, through Be, B to C and then decreasing to Ne,  but this does not seem to correlate with other available data. The high carbon bond energy was then used to explain the hardness of diamond, but what about the slipperiness of graphite? Simplifying concepts is certainly necessary in these sort of activities, but presenting an inaccurate picture and more importantly an erroneous prediction of bond strengths seems less than ideal. It seems to me that this has suffered from the over use of hybridisation (which in general is a bad way to explain bonding) and  lack of understanding of molecular orbital theory (which is a much better way to explain bonding, although admittedly there is the complication of explaining the difference between the ordering in O2 and N2) which has been compounded by extrapolating from diatomics to solid state compounds.

Did no one else spot this?

UPDATE. Posted by Mark:

Peter Wothers has very kindly taken the time to explain his thinking behind his model.

Having come up with this idea of a model, perhaps I should clarify.

What I was trying to get across was the idea of bonding orbitals and antibonding orbitals. The confusion comes from the model suggesting that it ONLY refers to diatomics whereas the data in the chart is for essentially the enthalpy of atomisation of the period two elements in their standard states. The graph used real data which clearly shows carbon with the greatest enthalpy of atomisation. (As an aside, let’s not forget graphite is not slippery in a vacuum!)

Of course the simplified diagrams given in the diagrams quoted are approximately correct for diatomics, but the picture is more complicated for solid states when band theory would provide a better starting point. However, whether in solids or diatomics, the idea that some electrons help to bond atoms together whilst some actively pull them apart is a key one which the model tried to illustrate. This is not an idea commonly met with at schools.

Personally, I would not go into hybrid orbitals, but in order to understand the bonding in the standard state of the elements lithium to fluorine, we should use the 2s orbitals and three 2p orbitals. The maximum bonding is reached for carbon since each carbon atom supplies enough electrons (4) to the bulk to fill completely the bonding levels this was what the bonding model was meant to show.  Sadly, this clearly misled since some people thought it was talking about the bonding in C2 molecules.

I accept that the model is not perfect (how could it be?) but I personally thought it better than “dot and cross” diagrams and might introduce young students to a new idea.

Sorry if it’s confused people instead.


By December 27, 2012 6 comments general chemistry, Uncategorized