Movement of air pollution

Featured article

Stavridou, H. and Marinopoulos, D. (2001) 'Water and air pollution: Primary students' conceptions about "itineraries" and interactions of substances', Chemistry Education: Research and practice in Europe, 2(1), pp. 31-41.

This paper reports a research study by the authors that explored three questions about the thinking of students aged 11-12.

1)    The ways pollution is produced.
2)    The possibility of movement of different substances in the atmosphere or in water.
3)    The possible conservation or interaction of substances in the atmosphere or in water.

The study was undertaken in seven primary schools in Volos, Greece with 229 students taking part in the experimental classes and 170 in control classes.The focus of the study was on whether the developed teaching intervention improved understanding between a pre and post-test. The paper was published in 2001.

The part of the paper that inspired my thinking was the results of the pre-test relating to the movement of air pollution which showed the understanding (or lack of understanding) of students at the start of the study. 

Question 1

If exhaust fumes and other harmful gases emitted from central heating and factory chimneys appear in a distant place, from which of the following places do you think they could finally reach Volos?

Over 96% of students thought air pollution could reach Volos from nearby towns and villages.
About 50% of students thought air pollution could reach Volos from Italy and only about 28% thought it could reach from the USA.

Question 2

If car fumes, central heating fumes and fumes emitted from factory chimneys appear in Volos, to which of the following areas do you think they can go?

Over 96% of students thought air pollution from Volos could reach nearby towns and villages. Only about 45% thought that air pollution from Volos could reach Italy and only 25% that it could reach the USA.

Some students’ explanations for only selecting nearer places were that these harmful gases could only reach nearby areas and not faraway areas. This is not so much an explanation as a statement of what students thought to be the case.
Some students who that thought the air pollutants could move suggested that they [the harmful gases] could go everywhere because they are easily carried by the air.

The authors concluded that their teaching intervention about air and water had improved the answers of the experimental classes substantially.

A key recommendation from the authors was  that teaching should help students to understand the global dimension of pollution as well as the ways air pollutants transfer from one place to another. They suggest that the science curriculum should include concepts relating to the diffusion (and dilution) of pollutants in the atmosphere as well as the movement of air masses.

BEST Diagnostic Question

Pollutant locations

In which location could air pollutants be present?

A    country road                
B    city                
C    mountain                
D    motorway                

[Image credits: country road http://clipart-library.com/clipart/1733136.htm
city  https://www.wpclipart.com/buildings/city/city_other/city_clipart.png.html
mountain  http://clipart-library.com/clip-art/mountain-clipart-transparent-background-1.htm
motorway Image by Clker-Free-Vector-Images from Pixabay]

Reflective questions

Do you think that all your students understand the movement of air pollutants or do you think that some  students may hold misconceptions?

To what extent do you explicitly teach about the movement of air pollutants?

What are the implications of any misconceptions about the movement of air pollutants on understanding causes of increasing carbon dioxide levels in the atmosphere and ways to mitigate this?

Useful links

BEST Topic 1 Key concept 1: Air quality

Diagnostic question to check for student misconceptions about air quality as part of a five-part progression (including response activities).

University of York Science Education Group

The mole - unit and concept

Featured paper

Fang, S.C., Hart, C. and Clarke, D. (2014) 'Unpacking the meaning of the mole concept for secondary school teachers and students', Journal of Chemical Education, 91, pp. 351-356.

This paper reports the findings of an in-depth content analysis relating to the concept of the mole. This content analysis was used by the authors to form of a concept map. 

Unlike other SI units such as the gram and the second, the mole is often described as the "mole concept". The concept map provides a visualisation of the interconnected sub-concepts that are needed to understand the wider mole concept. The authors suggest that the concept map could be a useful tool for teachers in thinking about how they could meaningfully teach the mole concept to students.

Please note that the authors used the  IUPAC definition of a mole that was valid at the time of publication  rather than the most recent version.

A mole is the amount of substance which contains as many elementary entities as there are in carbon atoms in 0.012kg of carbon-12.  When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particle or specified groups of such particles.

The authors created a concept map (illustrated below) to show how specific sub-concepts connect to enable an overall understanding of the mole concept. 

The authors describe the idea of the amount of substance (in moles) as being the bridge that links the number of elementary entities to the mass of a substance.

The concept map includes some sub-concepts that are linked to understanding of atoms, molecules and relative atomic and molecular mass as well as sub-concepts linked specifically to the mole concept. Identification of the importance of the atomic-molecular concept in understanding the mole concept was a key outcome of the content analysis. 

The atomic-molecular sub-concepts link to the mole concept in two different ways.

Link 1 - connecting the sub-concept of atoms and molecules to the number aspect of the mole concept

This idea connects the concept of a single atom or molecule (or other elementary entity) with the idea of thinking about a ‘standard pack’ of atoms or molecules called the mole.
This idea of aggregating atoms or molecules into a “standard pack” does not explain to students why the number 6.02x10^23 was chosen as the number in this “standard pack.” This number is not mentioned in the original definition of the mole.
The authors suggest that students are taught that the number of atoms in 12g of carbon-12 was experimentally determined to be 6.02x10^23.

Link 2 - connecting the sub-concept of relative atomic or molecular mass to the mass aspect of the mole concept

By definition, one mole of any substance always has the same number of elementary entities as 12g of carbon-12. If the number of elementary entities of different elements are the same, then the ratio of their masses will be the same as the ratio of their atomic or molecular masses.
Due to the choice of 12g of carbon-12 being the measure of one mole, the relative atomic mass of any other element in g will also contain one mole of atoms.

The authors alert teachers that this understanding requires students to use proportional reasoning. 

Consequences for teaching

The authors recommend that in order to meaningfully teacher students about the mole they should guide students to make the connection between the atomic-molecular concept to both the number and mass aspects of the mole concept. 

BEST Diagnostic Question

Relative atomic mass

Every element has a relative atomic mass.
You can find the relative atomic mass of an element in the Periodic Table.
Which answer best states the relative atomic mass of helium?

A 4g
B 4mg
C 4
D 4x10^-9g

The correct answer is A. Relative atomic mass does not have a unit.
A student who chooses option A may hold the misconception that relative atomic mass is the same as the molar mass, which is measured in g.
Selection of option B or D may suggest that a student thinks that relative atomic mass is the mass of an actual atom (which is smaller than a gram).

Reflective questions

How do you first introduce the mole? 

What connections do you make with earlier understanding?

To what extent does the current definition make the mole concept easier or more difficult to understand?

The current IUPAC definition of a mole is:
The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.02214075x1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in mol^-1, and is called the Avogadro number.

Useful links

BEST Topic 6 Key Concept 1: Amount of substance

Diagnostic questions to check for student misconceptions about the atomic model as part of a five-part progression (and including response activities)

University of York Science Education Group

Welcome to the SciEd Distillery

 

Being “research informed” is considered essential for anyone working in education but a huge swathe of the research literature is inaccessible to anyone who does not work in a university setting.

During the four years that I worked for the University of York Science Education Group as the chemistry lead on the Best Evidence Science Teaching project I searched out chemistry education research papers that identified misconceptions of students aged 11-16.

More recently I have been working for the Centre for Industry Education Collaboration trawling the science education literature relating to the misconceptions of primary children (aged 5-11).

Many of these papers related to small studies and individually do not draw conclusions that are significant enough to have a direct impact on changing practice in the classroom. However, some of the papers made me stop and think about the curriculum and how science is taught. These are the papers that I am planning to feature in the SciEd Distillery. 

This blog uses the metaphor of a distillery to encapsulate the process by which I shall be distilling these thought-provoking ideas from more lengthy research papers.   

These ideas will not tell you what the research advises you to do but my intention is that they will support you to reflect on your own practice.

Having had the time and opportunity to explore the research literature I am now looking forward to sharing more widely the essence of some fascinating research relating to science education.