One of the great things about being based at Victoria University is that there are always lots of events such as lunchtime seminars that you can go along and attend. One I went to recently was called Communicating Controversial Science. It was presented by Dr Rebecca Priestley and Dr Rhian Salmon who are both lecturers in the School of Chemical and Physical Sciences.
The seminar focused on how scientists can go about communicating 'controversial science' to the public. Just about any area of science can become controversial, but some of the examples we were looking at were fluoridation of water supplies, vaccinations, climate change, nuclear energy, cloning, genetically modified food and nanotechnology.
In the seminar we divided into three groups - chemists, nanotechnologists and nuclear scientists. Firstly each group took the perspective of members of the public concerned about one of the other two areas. We listed concerns that people might have. For example, people worried about nuclear power might have concerns about radioactive materials getting into the environment or a nuclear accident such as happened at Chernobyl. The 'specialist' groups then considered those concerns and discussed ways to communicate the relevant science to the public in order to reassure them.
Until about 2000 the main model used by scientists when communicating with the public was what is now referred to as the deficit model. This model assumed that people knew very little about the relevant science and the scientist's role was to educate them. It was thought that once people had been informed of the scientific facts, they would change their views and support the new technology or scientific theory. However, this approach has been shown to be largely ineffective. This is partly because it does not take into account people's existing knowledge (which may or may not be scientifically accurate), or their beliefs and personal experience. Critically, it does not provide for people to have their say and enter into any dialogue with the scientist.
After 2000 a dialogue model of science communication became more commonly accepted. Under this model the scientist and non-scientist engage in discussion where the non-scientist is able to voice their perspective, understandings and beliefs. However, the scientist still views their role as one of bringing the other person around to accepting the science viewpoint.
This model has now evolved further to an engagement model. This model recognizes that effective science communication requires a genuine respect for people's current knowledge, values, perspectives and goals. The objective is not to convince people to adopt your viewpoint, but rather to provide expert knowledge and to then accept that people will use a combination of that scientific knowledge and their own understandings and values when deciding what position they will adopt. Decisions around the application of scientific knowledge in communities are the responsibility of all members of the community. It is the role of scientists to bring scientific evidence to the debate, but all citizens have the right to participate in the debate, to have their own viewpoint respected and to apply their own values in their decision-making.
An interesting paper about the changing nature of science communication can be found at: http://tinyurl.com/qbp4wxq
Thursday, 20 March 2014
Friday, 14 March 2014
Cyclic Loading
Right, back to the business of hunting for undiscovered molecules in our red algae (seaweed). You may remember that we have got as far as extracting a whole range of molecules which are now sitting in solution in a conical flask. The next step is to start separating the molecules into groups. To do this we are going to use the varying polarities of different molecules.
In class we have looked at covalent bonds having different degrees of polarity depending on the difference in electronegativity of the two atoms involved in the bond. Some bonds are not polar at all (non-polar) while others may be only slightly polar or very polar. We have tended to classify molecules as either non-polar or polar and left it at that. However molecules also have varying degrees of polarity. For example, water is more polar than methanol which is more polar than acetone. We are going to use the relative polarities of these three solvents to help us to separate our mixture of molecules.
To begin with the second extract is passed through a column filled with 'HP20'. HP20 is comprised of small white beads of polystyrene divinylbenene. These beads provide a very non-polar surface that molecules can attach themselves to. Molecules will do this if their polarity is closer to that of the HP20 than it is to the polarity of the solvent they are in. So molecules in the mixture that have a low polarity will come out of the moderately polar methanol solvent and attach themselves to the HP20.
Solution that passes through the column is collected in a conical flask at the bottom. The flow rate is about one drop per second so it can be quite a slow process. Once the second extract has passed through the column, it is the turn of the first extract which is loaded into the top of the column. Eventually both extracts have passed through the column and the solution containing all the molecules that have not attached to the column is in the conical flask at the bottom.
We now want to encourage some of the slightly more polar molecules onto the column. To do this we need to make the solvent more polar. This is achieved by doubling the volume of the solution by adding distilled water. Remember that water is more polar than methanol so the solvent (now a mixture of water and methanol) is more polar than it was before. The solution is put through the column again and this time some of the slightly more polar molecules attach to the column. This process is repeated one more time to make the solvent even more polar and to cause more molecules to attach to the column.
Molecules of high polarity will not, of course, attach to the column as they will prefer to remain in the polar solvent. This is not a problem for us as the molecules that we are hunting for do not tend to be of high polarity. However, just in case something important is still in the solution, we will keep it in the meantime.
In class we have looked at covalent bonds having different degrees of polarity depending on the difference in electronegativity of the two atoms involved in the bond. Some bonds are not polar at all (non-polar) while others may be only slightly polar or very polar. We have tended to classify molecules as either non-polar or polar and left it at that. However molecules also have varying degrees of polarity. For example, water is more polar than methanol which is more polar than acetone. We are going to use the relative polarities of these three solvents to help us to separate our mixture of molecules.
To begin with the second extract is passed through a column filled with 'HP20'. HP20 is comprised of small white beads of polystyrene divinylbenene. These beads provide a very non-polar surface that molecules can attach themselves to. Molecules will do this if their polarity is closer to that of the HP20 than it is to the polarity of the solvent they are in. So molecules in the mixture that have a low polarity will come out of the moderately polar methanol solvent and attach themselves to the HP20.Solution that passes through the column is collected in a conical flask at the bottom. The flow rate is about one drop per second so it can be quite a slow process. Once the second extract has passed through the column, it is the turn of the first extract which is loaded into the top of the column. Eventually both extracts have passed through the column and the solution containing all the molecules that have not attached to the column is in the conical flask at the bottom.
We now want to encourage some of the slightly more polar molecules onto the column. To do this we need to make the solvent more polar. This is achieved by doubling the volume of the solution by adding distilled water. Remember that water is more polar than methanol so the solvent (now a mixture of water and methanol) is more polar than it was before. The solution is put through the column again and this time some of the slightly more polar molecules attach to the column. This process is repeated one more time to make the solvent even more polar and to cause more molecules to attach to the column.
Molecules of high polarity will not, of course, attach to the column as they will prefer to remain in the polar solvent. This is not a problem for us as the molecules that we are hunting for do not tend to be of high polarity. However, just in case something important is still in the solution, we will keep it in the meantime.
Thursday, 13 March 2014
A Professor Visits
Recently I was lucky enough to attend a Tertiary Chemistry Teaching Symposium held here at Victoria University. It was a gathering of chemistry lecturers from different universities around New Zealand and had a particular emphasis on teaching and learning in First Year chemistry courses. The lecturers shared ideas and discussed common challenges that they were facing. One of those challenges is that different schools cover different NCEA Level 3 chemistry achievement standards and therefore students in a First Year chemistry course can have a range of backgrounds in chemistry. This, of course, makes it challenging to design First Year chemistry courses. The lecturers were particularly concerned that not all students were doing the three external NCEA Level 3 chemistry standards.
Guest speaker at the symposium was Professor Roy Tasker from the University of Western Sydney where he is Professor of Chemical Education. Professor Tasker's presentation was on Visualisation of the Molecular World for a Deep Understanding of Chemistry. His key message was that to understand the chemistry that we observe (for example, a precipitate forming) we need to be able visualise what is happening at a molecular level, rather than jumping straight to writing a chemical equation.
Professor Tasker's team are responsible for producing the VisChem videos that we sometimes watch in class. These videos, showing animations of chemical reactions at the molecular level are now available to anybody through Scootle - tinyurl.com/VisChemOnScootle
A YouTube video on VisChem Learning Design, which demonstrates best practice in using molecular animations in the classroom can be found at: tinyurl.com/k2x34sr This approach involves students observing a chemical reaction, recording their observations and then producing a storyboard to show what they think is happening at the molecular level. They then discuss their storyboard with a peer before being shown the VisChem animation. After viewing the animation students then reflect on any similarities and discrepancies between their representations and the animation. Finally what is happening at a molecular level is linked to how that can be represented by a chemical equation. This approach is a constructivist one which takes into account a student's current model of what is happening. It involves cognitive conflict as a student's previously held perceptions may be challenged by what is in the animation.
If you are interested in seeing some amazing animations of molecules at work in living things, you might like to have a look at a video of a presentation by Drew Berry called Animations of Unseeable Biology - tinyurl.com/7tkh9zw
Guest speaker at the symposium was Professor Roy Tasker from the University of Western Sydney where he is Professor of Chemical Education. Professor Tasker's presentation was on Visualisation of the Molecular World for a Deep Understanding of Chemistry. His key message was that to understand the chemistry that we observe (for example, a precipitate forming) we need to be able visualise what is happening at a molecular level, rather than jumping straight to writing a chemical equation.
Professor Tasker's team are responsible for producing the VisChem videos that we sometimes watch in class. These videos, showing animations of chemical reactions at the molecular level are now available to anybody through Scootle - tinyurl.com/VisChemOnScootle
A YouTube video on VisChem Learning Design, which demonstrates best practice in using molecular animations in the classroom can be found at: tinyurl.com/k2x34sr This approach involves students observing a chemical reaction, recording their observations and then producing a storyboard to show what they think is happening at the molecular level. They then discuss their storyboard with a peer before being shown the VisChem animation. After viewing the animation students then reflect on any similarities and discrepancies between their representations and the animation. Finally what is happening at a molecular level is linked to how that can be represented by a chemical equation. This approach is a constructivist one which takes into account a student's current model of what is happening. It involves cognitive conflict as a student's previously held perceptions may be challenged by what is in the animation.
If you are interested in seeing some amazing animations of molecules at work in living things, you might like to have a look at a video of a presentation by Drew Berry called Animations of Unseeable Biology - tinyurl.com/7tkh9zw
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