Why does sodium chloride dissolve?

I recently came across a question on Twitter about sodium chloride (salt) dissolving in water. The question was effectively: “If the bonds between the Na+ and Cl ions are so strong, why is water able to break these bonds?” 

There are probably several ways to answer this question and the most satisfying will probably involve mathematics that is way above my pay grade. However, I will attempt to offer an answer here that might help…

First, it might be useful to look at the particulate nature of matter. When you add a clump of sodium chloride into water, the water molecules will be constantly moving and random directions, and thus will constantly collide (I prefer the term interact but let’s stick with collide in this explanation as it is more visual) with the sodium chloride lattice. This means that there is every chance (although small) that a highly energetic water molecule will hit one of the ions and transfer enough energy to it so that it overcomes the attraction to the other ions. Once this ion is “free” from the lattice, it collides with many water molecules which can form an attraction to it and so “surround” it. This is a relatively energetically stable state. 

Secondly, it might be useful to think of bonds in degrees of transience. They are not permanent, since electron clouds are constantly fluctuating. This means that at any one point, there is a chance that a single ionic bond on the edge of the lattice is weakened. This means that less energy is needed to overcome that bond, and so if an energetic water molecule hits that ion at the right time, then it will be “released” from the lattice. Then the water molecules can interact freely and “surround” it, forming the more energetically stable hydrated ion. 

These two ideas are highly dependent on probability. If you leave a clump of sodium chloride in a glass of water and do nothing, it will dissolve relatively slowly. This is because the likelihood of the above happening at room temperature is relatively low. However, once it does happen, the likelihood of the hydrated ions returning to the lattice is even lower. Hence, gradually, the salt will dissolve. In actual fact, we very rarely leave the clump of salt to dissolve naturally. We will either heat the water (thus increased the average kinetic energy of the ions in the lattice and the water molecules) making the above to occurences more likely or we will stir the water, making it much more likely that the water collides with the lattice, again increasing the chances of the above happening. 

I hope that explanation is useful. As ever, I would love the hear the thoughts of other teachers who might be able to pick holes in this explanation (or indeed tell me that it’s completely wrong!). 

Using a Chemistry Glossary

In this short post, I will briefly discuss how I use a glossary of chemistry terms to support student learning. You can find the glossary here. Feel free to make a copy and use as you see fit (please note that it is a live document and so is constantly updated as I teach!).

Why use a glossary? 

Glossaries can be useful for a variety of reasons, and each person will have their own ideas about why they are important. For me, they help in a few ways:

  • Help me as the teacher keep track of what terms I would like learners to understand and be able to use
  • Help learners keep track of terms that will be useful in building their chemical expertise
  • Support learners whose first language is not English by giving them a resource to refer back to
  • Somewhere to record the learning from completing Frayer models during lessons

What is the glossary? 

The glossary utilises the idea of a Frayer model (if you’re not familiar with the Frayer model then check out this awesome resource). 

It consists of the following:

  • The word
  • The definition
  • Facts/characteristics of the word
  • Examples of the word
  • Non-examples of the word 
  • Sentences showing the word used in context

How might you use it? 

A glossary of terms is probably only as good as what you do with it. Here are some ideas of how it might be used:

  • As a tool for teachers so that they can see what terms learners should be familiar with. This might help them with their planning. For example, they might be thinking that they need to teach about the term “substance”. The definition for this might be “a particular kind of matter with uniform properties.” Immediately, the teacher might be thinking, “well, in order to understand what a substance is, students will have to be familiar with the terms “matter, uniform, properties and uniform properties”. This almost provides a sequence of teaching for building up to a solid understanding of the term “substance.”
  • Make a copy of the glossary and delete everything except the word and their definitions. Learners can then fill in the facts/characteristics, examples and non-example as they encounter the terms during lessons. You might have them complete Frayer models beforehand. You can then revisit certain terms periodically to see if learners can add any more examples or non-examples. 
  • Have a completely empty glossary that learners complete as they move through the course
  • Periodically, learners could be asked to use the glossary for some retrieval practice. This could be done in several ways. It could be printed and folded so as to create a set of flashcards. Or learners could just try writing out from memory. Again, it is what you help teachers and learners do with the resource that makes is useful, rather than just having it. 

This list is far from exhaustive! How might you use such a tool?

How to quickly make retrieval practice tasks…

Research suggests that fill in the blank questions are more effective at helping students encode knowledge into long term memory than multiple choice quizzes. This is because they have to actively retrieve knowledge from their memory in order to answer them, rather than just select that correct answer.

This blog post gives a quick and easy way of building such retrieval practice exercises that utilise this idea.

Consider this multiple choice question from the IB on energetics. You can quickly turn this into a fill in the blanks exercise in some simple, quick steps.

A multiple choice question from the IB

Steps for quickly turning an MCQ question into an effective retrieval practice exercise

  1. Simply copy the statements into a presentation.
  2. Change the wording in A, B and C so that they are correct statements.
  3. Make a copy of this slide.
  4. Delete the words that will illicit understanding. For example, in D, I would delete the word “greater” as if students get this correct, it will demonstrate their knowledge.
  5. In the copy of the slide, highlight that word in red so that students can get immediate feedback. This will utilise the hypercorrection effect.
  6. BONUS: You can add a statement that says “explain your answers” in order to get students to elaborate on their understanding.

Here is the final product:

Slide 1 (Retrieval Practice Exercise) Slide 2 (Answers for immediate feedback)

Effective Learning and Revision Strategies

This post is designed to give parents and students a really brief insight into some practical strategies that might improve learning and make time spent on it more effective.

It is split into two parts. Part 1 looks at a how you might get started with revision and what the cycle of revision certain content might look like. Part 2 looks at some principles of effective learning. They are very general at this point. Part 3 suggests some further reading for students and parents who are interested. There are also some links to further strategies that might also be useful.

The post is designed to act as a starting point for parents and students to look more into effective learning and what it might look like for them.

Part 1: Effective Revision

Plenty of students work really hard. However, many don’t know how to learn, revise and study effectively. Many think that just reading their notes is good enough. This often lulls them into a false sense of security. “I’ve read everything, so therefore I have revised.” However, research suggests that this is a really ineffective use of time in terms of embedding things into the long term memory.

Hopefully, this section gives students an insight into how they might organise their time so that they spend more of it looking at content they don’t know yet, and then use strategies that are the most effective use of their time.

Assess Current Understanding

  1. Go through assessment marks and rank units in order of priority
  2. Take past paper tests on a unit or chunk of information
  3. For anything that you got right, go back and mark this as green in your booklet
  4. For anything that you got wrong, go back and mark it as red

Re-learn specific content

  1. Use booklet, textbook and trusted videos to make dual coded notes (text turned into diagrams and vice versa – see below for more info) on content that you did not know (from taking the practice test)
  2. Make flashcards on this content and then use them to learn content (using a specific strategy)
  3. Use the content to make your own mini-tests with answers and complete these tests repetitively over time until you get them correct 100% of the time. Mark tests immediately and then look over the content again, but leave some time between completing the tests so that ideas can enter your long term memory more effectively.
  4. Any of the retrieval practice exercises you have learned or have been shown.

The diagram below represents this in a more visual way. (note, this is an example of dual coding – see part 2).

Screenshot 2019-02-14 at 12.18.27.png
A graphic organiser that suggests how students might navigate entering the revision cycle (this is also an example of dual coding)

Part 2: Principles of effective learning

Research suggests certain principles that might make learning more effective. There is no one magic bullet for learning.

The main takeaway though is that just reading through notes is not effective. Neither is just re-writing notes again and again.

Below is a table of some principles, with a short explanation and then some potential strategies. The list is by no means exhaustive, but all of the principles should be incorporated into a revision strategy in some way. Students are encouraged to be inventive with how they put these principles into practice.

Principle Explanation Some Potential Strategies
Retrieval Practice Research suggests that regularly trying to retrieve content from your memory helps embed knowledge and understanding into your long term memory. It is important to note that this can be demoralising as students discover what they don’t know. It is important to approach this with the right mindset!
  1. Past Paper Questions
  2. Drawing Concept Maps from Memory
  3. Re-writing explanations from memory
  4. Create tests from your study notes using Quillionz (unfortunately this only works with text)
Dual Coding Research suggests both verbal and non-verbal processing are important in making connections in learning. Drawing diagrams helps you to make connections that you might not make when writing/saying and vice versa.
  1. Using written explanations to draw annotated diagrams
  2. Creating written explanations using a diagram
  3. Breaking down explanations and process into flowcharts or cartoon strips
  4. Representing concepts and relationships between concepts as Venn diagrams
  5. Using graphic organisers to sequence and order knowledge and create connections between them
Spaced Practice Research suggests that spacing learning over time is more effective in terms of storing knowledge and understanding in our long term memory. This means regular periods of revision starting now, rather than cramming during study leave.
  1. Creating a revision timetable and writing what content you will study and how (look at strategies given).
  2. In your revision timetable, leave gaps between revisiting a certain unit. For example, if you study C1 on Monday, study C2 on Tuesday, C3 on Wednesday and don’t come back to C1 until Thursday.

Further reading

  1. The Learning Scientists have a great website that looks at the science behind learning. This is essential reading for parents and students (link). They also have a great book called “Understanding How We Learn: A Visual Guide” (link). It is really clear and offers great strategies for learning and goes a bit deeper into some of the experiments and theory that support this.
  2. A really nice post from the Cult of Pedagogy on Retrieval Practice (link). Could a parent try any of these at home?

Using Google Quizzes for Retrieval Practice

I’m finding the quiz function in Google Forms is awesome. If you don’t know what I’m talking about or how to get to this, check out this video!

I use this primarily for retrieval practice and quick formative assessment. Here are some of the top benefits I find when using the quiz function in google forms.

1. Students can receive immediate feedback

If you set the quiz settings to release mark “Immediately after submission” (see the image below), students can see their marks for the quiz straight away. This allows them to immediately look at the questions they got wrong and try to figure out why.

2. You can utilise the hypercorrection effect

The hypercorrection effect (I got it from Dylan Wiliam but not sure if he coined the phrase or not…?) suggests that when students are super confident in an answer, but then get it wrong, they are much more likely to remember the correct answer once they work it out. For example, take the gollowing question:

What is the captial city of England?

A: London

B: Cardiff

C: Edinburgh

D: Manchester

If you are super sure that the answer is C (Edinburgh) but then receive the results and find out that the answer is A (London) then you are now much more likely to remember that the capital city of England is London.

In these multiple choice quizzes, it’s often the case that students are super sure in an answer but get it wrong because they fell for certain tricks! Making these mistakes and hypercorrecting them in the classroom setting could be great for learning!

3. You can make students think hard about the immediate feedback

If you change the settings on the Google Quiz to those in the image below, you can make students work a bit harder in the feedback process. According to a lot of Dylan Wiliam’s work, this can make feedback more effective. One suggestion Dylan Wiliam has for making multiple choice questions (MCQs) work harder is to give students a score for their quiz, but don’t give them the answers. The process of then working out which questions they got right and which they got wrong aids their learning. With the settings below, students will get a score, but won’t be told what the correct answers are. This means they have to revisit the question and look for their mistake and try to determine the correct answer.

4. Students can try the quiz again and again!

These quizzes are great for retrieval practice, and students can complete them again and again until they get full marks, if they do wish. They can also save the link and revisit the quizzes during revision. Studies show that students who engage in quizzing often commit more to long term memory!

5. The teacher can see questions that might require a re-teach

This is quite powerful. You can see statistics for each question. For some questions, all the students might get it correct, as shown below:

Seeing this data means that you can be pretty happy that the students understand the concept being assessed in this question. However, for some questions, you might see something that looks more like this:

This might suggest you need to reteach this concept. Of course, you might do this just for the students who got it wrong, or for the whole class. Depends on your style.

6. You can see the most popular wrong answer

Another way of using this (which I originally got from this post by Jennifer Gonzales – and she explains it much better than I do here) is to find the most common incorrect answer and see if this gives you any information. For example, imagine I got this data for the following question:

What is the captial city of England?

A: London

B: Cardiff

C: Edinburgh

D: Manchester

By knowing that the students that got the question wrong all chose the same answer, I might be able to deduce that all the students at least know that Cardiff and Edinburgh are not in England. This is an extra bit of information I didn’t have before.

7. Identifies students who have not completed the quiz

Another useful feature is that the quiz will show you who has not yet completed it. This allows you to follow up with these students and see what is stopping them from completing the quiz. One concrete example if when you set the quiz whilst one student is absent. When you look over the responses, you will notice this and might give that student a gentle nudge to complete the quiz at home.

8. You can collect data on individual students

I can see very quickly how students did, and more importantly, which questions they get wrong. This looks like the image below and allows me to visit that student and help them through the concept if need be.

These are just some of the ways that I find google quizzes useful. I’m sure there are many more and I would love to hear them!!!

Using the group 1 metals demonstration more intentionally

Throughout my teaching career, I have often found myself doing demonstrations because they are in the unit plan. I have, at times, not really used them with great intentionality. One of my goals this year is to be much more intentional with the demonstrations I use. This includes thinking carefully about the conceptual understanding I want students to reach, the learning progression, the questions I need to ask and the awareness I need to raise, and the things I need to take out or change in order to reduce cognitive load.

This activity uses the concept of ionisation energy and the demonstration of the reaction of the group 1 metals with water.  The intention is to allow students to apply their understandings of electrostatic forces of attraction with respect to the conceptual understanding given below:

“The strength of the electrostatic force between charged particles is dependant upon the size of the charges and the distance between the charged particles”

For this activity to be successful, students should have an understanding of what electrostatic forces are and why might affect their strength between particles. They should also have an awareness that electrons exist in energy levels based on the strength of the forces of attraction between the electrons and the protons in the nucleus. The concept of first ionisation energy should be spoken about in very simple terms so that they can access the graph. You can simply explain that it is the amount of energy required to remove the valence electron from the atom.

Activity Instructions

Part 1: Using understandings to make a prediction

Students complete use their prior knowledge and the graph shown in figure 1 below to answer the questions on the slide in the same figure.

Figure 1: The slide I used to introduce this demonstration and link it with content that had been covered previously

They then use this to make a prediction about how the reactivity of group 1 metals with water will change as you go down the group and add this to the table shown in figure 2.

Figure 2: A really basic table of observations. It doesn’t always need to be beautiful and fancy. If the learning engagement is interesting enough, functional will do! I often need to remind myself that.

Part 2: Making observations to test the predictions

1. The teacher should then carry out a demonstration of the group 1 metals reacting with water (make sure you are trained to do this and carry out a full risk assessment). Students are asked to write down their observations (what they see and hear) as they watch the demonstration. It is made clear that they can also write down observations made by the teacher, who is closer to the reaction.

2. The teacher should start by cutting the metals one after the other, starting with lithium and ending in potassium. As the teacher, you might need to state the following as you do this:

  • The metals are all kept in oil as they will react with moisture in the air and oxidise easily
  • The metals are easy to cut. Lithium is the hardest, sodium is next and then potassium is the easiest to cut.
  • They are shiny on the inside.

The students should then be given time to write down any observations and discuss these with a partner.

3. The teacher should then start with the reaction of lithium with water. Remind the students to write down everything they see and here. It should be clear that bubbles are being produced but you may need to say this if the reaction is not vigorous enough. It should also be clear that the lithium is moving around on the surface of the water. You might also need to make it clear to the students that the lithium retains its shape (i.e does not turn into a ball) as they may not be able to see this. Give students time to write down their observations and discuss with a partner and repeat the demo with lithium, just in case students missed anything.

4. Now repeat this process with sodium. Once the demonstration is finished, you might like to ask students what observations they have made. Depending on their answers, you might need to bring to their attention that following:

  • The sodium turned into a ball.
  • There was a time delay on the sodium producing a flame (and you might need to make it clear that this is an observation. This is an important teaching point that not all observations are obvious. This means we can often miss important information)

At this point, you might like to ask students to talk about the differences between their observations for lithium and sodium.

5. Next, the teacher carries out the reaction of potassium with water. Follow the same principles as previously mentioned. However, this time, you might need to point out that the potassium catches fire almost immediately!

Give students a couple of minutes to write down their observations and discuss.

6. Finally, ask students to discuss and write down an answer to the question in the final box in figure 2: To what extent do your observations support your prediction? It is important that students explain their reasoning. Some supporting evidence they might make are:

  • Lithium produced bubbles slowly when compared to sodium and potassium which suggests it reacted slower
  • Lithium did not turn into a ball whereas sodium and potassium did. This means it might have released less energy which might mean it is less reactive.
  • Potassium caught fire much quicker than sodium, suggesting that it released energy much more quickly.

There are probably more points. The important thing here is that students recognise the order of reactivity and can support this using their understanding of electrostatic attractions.

Reducing cognitive load

Since the main teaching point in this activity is to allow students to apply their understanding of how the strength of the electrostatic force of attraction between valence electrons and the protons in the nucleus affects reactivity, it is useful to remove extraneous ideas.

  • For this demo, teachers often add universal indicator. For this activity, it has been deliberately left out. This is because talking about the production of alkaline substances is not useful to this teaching point. The demo can be repeated at a later more relevant date with this teaching point in made
  • Teachers also talk about the production of hydrogen gas and the metal hydroxide. Again, this is not useful for the main teaching point and so is not touched upon here (other than the observation that bubbles are produced during the reaction).
  • Teachers often ask students to write the balanced symbol equations for this reaction. Again, this is not supportive of the main teaching point. If you wish students to write the balanced symbol equation, it may be more useful to revisit the demonstration at a more suitable point.

Final points

Thanks for taking the time to read this post. I would love to hear some feedback from anyone trying this out. I would also be interested to hear from anyone who is interested in conceptual understandings in chemistry and how we might reduce cognitive load during lessons. Please, comment away! Constructive criticism always welcome.

Developing better internal schema in chemistry students

Pre-warning. This is a bit of a long read and gets a bit heavy. If you want to skip to the final summary, scroll down! Disclaimer: A lot of this article is based on the work of Talanquer (2015). Barely any of it is my own so please do take a look at his article for the original work. 

As discussed in this post, ontological components make up part of the complex cognitive process that help students to access an understanding of threshold concepts. The ontological component involves learners developing schema that help them to think about the nature of the entities and processes present in the systems that they are studying. Further, it involves them thinking about the nature of the relationships that exist between these entities and processes.

Talanquer (2015) outlines five internal schema that students of chemistry often have which might limit their understanding and ability to develop expertise in the subject. He then goes on to outline some internal schema that we might help students develop so that they are better able to develop said expertise. In order to move from these ‘limiting’ internal schema to the more ‘adaptive’ internal schema, we might scaffold the experiences of the students so that they can uncover conceptual understandings that help them ‘see’ the chemistry world in a more flexible manner.

The five ‘limiting’ internal schema are outlined in the diagram below, along with the more ‘adaptive’ internal schema that we hope students of chemistry will attain. You can see that the key to unlocking the more powerful schema could be carefully thought out conceptual understandings. Some ideas for some conceptual understandings that will aid this transition are suggested in the coming sections of this article.

Screen Shot 2018-06-14 at 20.26.18 1.png

From the additive property to the emergent internal schema

The problem with students seeing chemistry with an additive property scheme is that they think the everything in chemistry is the sum of its parts. In this schema, if you add one atom to another, it has twice as much mass, twice as much energy, twice as much everything! Another example might be a student thinking that more energy is required to break the bonds of a molecule with more bonds. However, we know that  this is not necessarily the case (think about double bonds vs single bonds). In this schema, particles have a known, concrete state and are not dynamic in nature. They are not affected by time and space.

Instead, it is suggested that students develop an emergent internal schema. Here, students recognise that systems in chemistry are dynamic, sensitive to time and space. They also recognise that measurable properties are average values of targeted quantities (e.g., number of particles per unit volume, kinetic energy per particle) over the many configurations of the measurements timespan (Talanquer, 2015).

Some conceptual understandings to move students from the additive property to the emergent internal schema might be:

  • The microscopic domain involves complex, varied and dynamic interactions between particles that are sensitive to space and time
  • Interpretations in the macroscopic domain involve averaging the many interactions and configurations in the measured timespan of the microscopic domain

From the centralised causal to the emergent internal schema

In the centralised causal schema, students view particles as protagonists. Fluorine wants to gain an electron so it can be happy and get a full outer shell. An acid donates a proton to a base so it can become more stable. In this schema, particles are often deemed as having goals that should be met in order to reach a more desirable state. According to Talanquer (2015),

“Highly reactive substances are commonly seen as the initiators in chemical reactions, and changes in the properties of a solution are often attributed to the active action of solute particles on solvent particles”.

This idea of protagonists and causation is embedded in everyday human life. Therefore, it is not surprising that students come to visualise chemistry in this way. It is very comforting and indeed, I often find myself falling into this schema. It is often the easiest (dare I say, laziest…) way to explain something in chemistry.

However, we know that observable properties at the macroscopic domain are due to dynamic, random and continuous interactions of particles at the microdomain. There are a multitude of random interactions occurring at the same time throughout a chemical system and the macroscopic outcomes of these interactions depends on relative probability of random events occurring, and this depends on internal and external constraints placed upon the system. For example, fluorine can quite happily exist as an atom with an unpaired electron if it is given enough energy. It doesn’t ‘want’ to gain an electron to become more stable. It is just that in certain situation, the external and internal pressures on fluorine will lead it to do so.  

So, some conceptual understandings to move students from the centralised causal schema to the emergent internal schema might be:

  • Observable properties at the macroscopic level emerge due to dynamic random and continuous interactions of particles in the micro domain
  • Internal and external constraints placed upon a system affect the relative probability of dynamic random interactions between particles occurring
  • Observable properties at the macroscopic level emerge due to the relative probability of random events occuring in the microscopic domain

From the homogenous population to the varied population schema

Personally, I think this is one of the most important realisations that a student can make. Students who see chemistry through the homogenous population schema think of all the particles of the same type as identical, rigid objects moving at the same speeds (Talanquer, 2015). This understanding might stem from a lack of understanding of what a chemical equation is representing. For example, in the equation A + B → AB , students often think of a single atom of A reacting with a single atom of B to give a single molecule of AB. In this schema, students would think that all particles of A and all particles of B will turn into AB at the same time.

However, particles of the same type in a substance are not all the same. A very simple example is that of kinetic energy. We know that particles of the same type in a substance may have different kinetic energies. This affects their ability to react when colliding with other particles. In the above example of A + B → AB, this means that not all of A can react with B at the same time! Hence why we use temperature as a measure of average kinetic energy. In a substance, there are constant variations and interactions occurring that mean that not all the particles are the same. Further, students should understand that chemical and physical changes that seem to follow a clear direction at the macroscopic level are due to random fluctuations in the spatial and energetic distribution of particles at the microscopic level. Without developing this internal schema, it might be very hard for students to grasp fundamental concepts such as equilibrium.

So, some conceptual understandings to move students from the homogenous population schema to the varied population internal schema might be:

  • Particles of the same type in a system may have different properties and this impacts the behaviour of the system and is a major source of change in multiparticle systems (wow, this is clunky…)
  • Macroscopic changes occur due to random fluctuations in the spatial and energetic distribution of particles in the microscopic domain in a system

From the intrinsic chemical property to the extrinsic chemical property schema

This was a bit of a revelation for me. In the intrinsic chemical property schema, learners will often see the chemical properties of a substance as an intrinsic characteristic that determines its behavior under all conditions (Talanquer, 2015). For example, they might expect a strong acid to be strong in all situations. However, should hydrochloric acid be thought of as a strong acid when placed in non-aqueous conditions? The answer, I think, is no. Therefore, it is not the intrinsic properties of hydrochloric acid that define it as a strong acid. It is instead the impact of external particles and conditions, such as the presence of water molecules. Indeed, the chemical properties of a substance are actually caused by the environment in which they are placed. They are extrinsic in nature.

When adopting the extrinsic chemical property schema, learners are able to think of chemical properties as relative and dependant on the nature of interaction systems. A student who does not understand this might have a hard time understanding that water can act as a base when placed in the same environment as hydrochloric acid, but as an acid when placed in the same environment as ammonia!

To help scaffold students transition to an extrinsic property schema, we might use the following conceptual understandings:

  • The chemical properties of a substance are dependant upon interactions with the substances in the environment in which they are placed

From the variation to conservation schema

I have a confession to make here. I struggle to understand this one fully. However, I will give it a go. Talanquer (2015) cites studies that suggest student reasoning is highly constrained by explicit clues, such as a change in physical appearance. As far as I read it, this means that students tend to focus on the changes that occur, and that this constrains the level of understanding that they can reach. It is human nature to detect changes in our environment and we are very good at it. We feel an urge to try and explain what causes these changes, but often pay little attention to explain what we perceive as the natural state of things. It takes individuals with astounding curiosity to ask the questions about the constants in the world around us. But, this is an issue, as chemists who have the aim of trying to explain, predict and control changes in the material, macroscopic domain often look to identify what is conserved during a process. This exemplified by fundamental principles like conservation of mass and energy. Focusing on these constants helps them find relationships between a systems components, and in turn allows them to think of ways to manipulate other systems. They recognize and exploit the constancy over time and space of properties of a reacting mixture (e.g., equilibrium constants, chemical potentials) to build predictive models. In order to adopt this schema of conservation, students must focus on the implicit, rather than the explicit (change in appearance) of chemical systems.

Some conceptual understandings that might (emphasis on the might) be of use here are:

  • Identifying what is conserved during a process helps chemists to predict and manipulate changes in the microscopic and macroscopic domains
  • Identifying relationships between a system’s components before and after a change helps chemists to predict and manipulate changes in the microscopic and macroscopic domains
  • The constancy over time and space of the properties of a reacting mixture can be used to build predictive models
  • Implicit properties in the microscopic domain can explain explicit properties in the macroscopic domain.

In summary

If you have made it this far, then I applaud you. The following table gives a short summary of this post and I hope you find it useful. I would love to hear some thoughts on this post. A lot is up for debate and I am not sure I have fully understood anything!

Screen Shot 2018-06-14 at 20.25.15.png


Talanquer, 2015: https://pubs.acs.org/doi/pdf/10.1021/ed500679k


War journalism is a well known and historical profession. Images of reporters risking their lives to report from conflict zones are known to many. However, this type of journalism is often propaganda like in delivery, focuses on the violence (and sometimes glamorises it), focuses on the suffering of one side and the actions of elites, and focuses on one side achieving victory. This type of journalism sells, but it does the world a disservice.

Far better is the notion of peace journalism. Here, reports might focus on the causes of conflict, the contributions of both sides, aims to expose the truth about all stakeholders, focuses on win-win solutions and focuses on everyday people.

Below, I have attempted to create a matrix (adapted from the work of Galtung, Jake Lynch and Annabel McGoldrick) that one should be able to fill out if reading a good peace journalism article. You could also fill it out before writing a blog post or article on a conflict. It’s a work in progress, so please do let me know what you think! Is it missing anything? What might you change? Is it useful? 

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A potential matrix to fill out in order to guide the writing of a peace journalism article

(EDIT: The original version of this post had “Side 1” and “Side 2”. A friend pointed out that this perpetuates the “us vs them” mentality and suggested party A and party B. Thank you!)

40 day breathing and meditation challenge

I recently completed a short course on breathing and meditation techniques. I really enjoyed the experience and so I am going to try to complete at least 20 minutes of practice for the next 40 days (and hopefully longer if it’s of benefit). My aim is to find some “calm in the chaos”.

Over the next 40 days, I will write a short reflection on my experience. I expect that to being with, they will be limited to just becoming more aware and will be relatively surface level. I hope that, as time progresses, they will become deeper and more profound. Who knows?!

I will update this post each day with my reflections, mainly for myself but also just in case anyone out there is at all interested.

Day 1: I found a nice quiet space at work and turned off the lights. Ideally, there should be some fresh air but this place had none. I’m hoping that during my holidays I will be able to find some nice places to carry out the practice outside. The practice has a clear formula to follow and I found much of my focus was on trying to follow this formula. This in itself was quite calming. During the practice, I became acutely aware of my fake tooth throbbing, which I haven’t felt for a while. Perhaps time to visit the dentist! After my third round of Ujjayi breath I started to get heart palpations! I get them relatively regularly but it is a bit annoying whilst trying to focus on breathing. I have to say, after the practice I felt quite good. I felt energised and all of my tasks (which were overwhelming at the start of the day) felt doable. I’m not sure how long that feeling will last, but it was nice for at least a little while!

Day 2: Today I completed my practice straight after getting out of bed at 6am and out on the balcony to get some fresh air. I found it quite tough this morning and did not get into a rhythm. I found it difficult to control my breath and I really didn’t enjoy it. I have no idea why, but it didn’t have the same calming effect on me that it did yesterday.

Day 3: Today, forgetting to carry out my practice before work and after work meant I was forced to do it in a public space in between commitments! There were people around and I have to say, I felt very self-conscious. It made me think about our focus on what others think of us. All I could think about whilst carrying out the practice (some of it might look weird to those that don’t know it) was what people were thinking of me as they walked by. Did these complete strangers think I was some weirdo? I know that I shouldn’t really care, but, hey, I did. Food for thought!

Conceptual understanding of epistemological issues in chemistry

As discussed in this post, epistemological components make up part of the complex cognitive processes that help students to understand threshold concepts. The epistemological components are to do with how arguments and explanations are built in a discipline.

In chemistry, this is mainly to do with the use of theoretical models (and how they differ from reality) and the use of experiments to collect data that supports these theoretical models. It is also important the students understand that new data can be used to disprove models or change and adapt them. Models are not static, and most likely never will be. Further, students should understand that models can be used to make predictions about interactions between particles and that, if the predictions prove correct, the validity of the model is further enhanced.

These conceptual understandings might help students understand the above points and at some point in the chemistry curriculum, it might be useful to scaffold students learning so that they can uncover these (by the way, these conceptual understandings need a lot of work – they are just a starting point):

  • Models can be used to conceptualise reality. Chemistry example: the atomic model is used to conceptualise atoms. 
  • Experimental information about light-matter interactions can be used to build arguments and theoretical models. Chemistry example: experimental information of light-matter interactions has led scientists to their current models of atomic structure.
  • Theoretical models can be used to predict the behaviour of unknowns. Chemistry example: Mendeleev predicting properties of missing elements in his early version of the periodic table went a long way to people accepting that this was a useful model for arranging the elements.
  • Theoretical models may change when new experimental information that contradicts the model is discovered. Chemistry examples: the development of the atomic model. Chemistry example: the Bohr model of the atom only works for Hydrogen and could not be used to predict the atomic structures of other atoms. New data led to the development of current models.

I believe that helping students uncover these conceptual understandings that link important ideas together will help them to reach a greater expertise and understanding in chemistry. What do you think?