Newly Qualified Teacher (NQT) support in chemistry

by Dr Robert Bowles. Guest blogger.

Dr Robert Bowles from the Royal Society of Chemistry (RSC) writes about the continuing professional development courses run in partnership with Science Learning Centres.

The Royal Society of Chemistry supports new or inexperienced teachers of chemistry (including those teaching ‘out of specialism’) to develop greater levels of confidence and expertise in teaching chemistry in the classroom.

In conjunction with the Science Learning Centres, the RSC has recently launched a new one day course, “Developing Expertise in Practical Chemistry”. At the RSC we call it “Chemistry for NQTs” as it is aimed at newly qualified teachers and it has been developed to focus on aspects of how class practicals, demonstrations and models can be used to enhance teaching and learning.

When you’re an NQT embarking on your teaching career, one of the hardest skills to master is how to deliver demonstrations and practical sessions effectively and safely to your classes. Knowing the mechanics of how to do an experiment or demo is one thing, being able to use it as a quality learning experience is quite another! This course provides a supportive environment in which NQTs have time to reflect on how they plan and deliver practicals and demos, whilst also having the chance to learn some new ones.

Many teachers also find it difficult to explain abstract ideas in chemistry – being able to use simple and then more complex models can be a really useful tool. When explaining abstract ideas, teachers often find themselves faced with students who have a bewildering number of misconceptions about chemical concepts; often stemming from the use of words which have one meaning in day to day use but a quite different and specific one in a chemical context.

For example:

A solution to a problem vs.  A chemical solution.

The Developing Expertise in Practical Chemistry course gives NQTs a chance to consider how models can be used to teach abstract ideas and concepts and empowers them to develop the best model to explode the misconceptions they are faced with in the classroom.

How fresh are your fruits? – A gas measurement exercise

By Richard Needham

This is a simple exercise involving measuring gases, which reveals some surprising secrets. It can give rise to interesting discussions around what we mean as scientists by the term ‘living’.

You can do this activity at any level in school – the data you collect could be used:

• Key Stage 1 – as a way of classifying fruits

• Key Stage 2 – what we mean by living and non-living

• Key Stage 3 – measuring respiration rates

• Key Stage 4 – planning investigations and photosynthesis

• Post-16 – investigating the effect of variables on biochemical reactions

I collected the data shown here at home in the kitchen one wet Sunday, so no special facilities are needed. I used a plastic box with two holes in the lid – one for a carbon dioxide sensor and one for an oxygen sensor. Mrs N kindly provided a couple of unripe avocado pears, which just fitted inside the box. I was surprised at how much carbon dioxide they released within a few minutes.

Measuring the respiration of an avocado

The graph below shows just how quickly the atmosphere inside the box changes. Note the gradients of the lines are difficult to compare as oxygen is measured as a percentage, whilst carbon dioxide is measured in parts per million.

Changes to oxygen gas (%) and carbon dioxide gas (ppm) over 60 minutes with single avocado

So are avocados unique? No they are not, as all the fruits I tested absorbed oxygen and gave out carbon dioxide. Some are far more active than others. For example my bananas absorbed oxygen three times faster than avocados. Grapes were slowest, again a result that surprised me as they have a huge surface area, and thin skins. When I measured gas exchange in grapes there was hardly any change shown after ten minutes. In the chart below, the data point for grapes is partially hidden by ‘apples’.

Gas exhange comparisons in fruits

Equipment used

1. Vernier bio chamber, with gaseous oxygen and carbon dioxide sensors attached to a laptop via a Labquest mini USB interface.

1. Vernier Logger Pro software for data collection and initial analysis, and then used Google docs to produce the comparative graph of results.

You should get similar results with any oxygen and carbon dioxide sensors providing they measure gaseous concentrations rather than dissolved gas. A sandwich box or ice cream container could be used in place of a proprietary bio chamber.

Questions and opinions that arose in discussions with colleagues

• Surely fruits are dead once they are picked from the tree?

Several colleagues assumed that once picked, a fruit becomes ‘dead’. Thinking about the ripening processes that continue this cannot be the case. However, some people assumed that the gas exchange shown in the data was a consequence of microorganisms and rotting processes.

•  But a mushroom is not a fruit.

To a biologist a mushroom cannot be a fruit as it is not a plant and does not possess the organs required for fruit development. Sometimes mushrooms are described as fruiting bodies (of basidiomycete fungi) and so I have no hesitation in justifying their inclusion in this investigation. Interestingly the data point for the mushrooms lies well below the line expected if these results are to be explained by aerobic respiration alone.

•  Why don’t green ones produce oxygen?

I initially thought that green fruits would be photosynthesizing, and produce very different results to those shown here. There is no way to tell if photosynthesis did influence the results, unless some further work is carried out, such as repeating at different light intensities.

•  How did you make it a fair test?

Good question. I am against the notion that scientific investigations always need to be fair tests. I did use similar masses of fruit in each case (about 420g) but did not attempt to control the effects of surface area.

•  Why would you want to do this?

I enjoy finding out things that are not readily explained by the science we teach in school. It challenges me to think deeper about what I am teaching, and leads to better understanding through discussion with others. Using sensors is one way of uncovering new information, and often turns up results that are unexpected.

And of course: Well how do you explain the results?

I will leave that question for you to answer.

Some useful links to help with your answers or planning

SAPS – Respiration and photosynthesis made easy

STEM elibrary- photosynthesis

Comments

I would be interested to hear your explanations for these results.

I would also like to know if these results are repeatable.

Also, do you have any examples of other ways that sensors can turn up unexpected results?

Halloween – The Three Hags

Late last night our cameras captured these three individuals who had  infiltrated our laboratories and were creating mischief.  It appears they were making plans for Halloween…..

Halloween 2011-vimeo

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On a more serious note this video demonstrates an effective way to tie in  a very popular date on the calendar with conventional science, and have some fun at the same time.  Here are some of the principles demonstrated in the video

Physics – The Stretchy Bugs are a great way of demonstrating forces at work, measuring them and experimenting to test how far the bugs stretch in relation to the amount of force applied.  Having different types of bugs helps as their stretchiness can then also be compared against the same amount of force.

Chemistry – The Slime is an excellent demonstration of a polymer.  It is also very easy to repeat and experiment with what happens when you vary the amounts of each ingredient going into it.

The explosion is the very simple and straight forward Custard Powder Flame Thrower.  This is a great demonstration for energy and can also be used to demonstrate the effect of surface area.

Here are the ingredients required for  Slime and the Custard powder explosion.

Slime

Custard powder flame thrower

Happy Halloween!

Ice Melting Blocks Demonstration

In this video Simon Quinnell presents the ice melting blocks demonstration. This is a great demonstration to get students thinking about the heat conductivity of different materials.

The Science Learning Centres run a number of courses to help you diffuse thinking skills into your teaching. Click on the links below for more information:

Developing Thinking Developing Learning

Promoting Thinking and Talking in Science

Ice Melting Blocks Demonstration

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Please ensure you undertake a full risk assessment before performing this demonstration and that it meets your institutions health and safety requirements. We also recommend you consult CLEAPSS or SERC.