Get to know Charlotte Pezaro: primary school teacher, PhD candidate and pre-service teacher educator.


Oh look, I’m hosting @edutweetoz this week! Follow along and join the conversation ;)

Originally posted on Edutweetoz:

Z4iMxU1s_bigger This week we welcome Charlotte Pezaro to Edutweetoz. Get to know more about her as she leads discussions and shares her passion for science and education with us.

Please tell us a little about your background in education. Why did you decide to become involved in education? What are some of the roles you’ve had and what does your current role involve?

I had nearly finished a Bachelor of Science (Psych) and didn’t feel ready to become a psychologist. I enrolled in some education courses, thinking I’d become a physics and biology teacher. I was assigned to a practicum at a kindergarten and was quickly hooked on primary teaching. I finished my BSc and enrolled in a GradBEd (Primary). I taught for six years on completion, at a variety of schools around Queensland, then enrolled as a PhD candidate. I also teach pre-service teachers about science, science education, and technology…

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High Expectations

When I graduated from my teaching degree, I had the absolute privilege and pleasure of working at Cherbourg State School, then managed by a charismatic and thoughtful principal, Chris Sarra.

Chris had started at the school four years previously, when it had been one of the worst achieving schools in the state. Cherbourg is a former government mission, established for “the protection of” Queensland (and Northern Territory, and New South Wales…) Aboriginal peoples. Chris, over the following years, collected a group of hard-working teachers and teaching assistants, and shifted the culture of the school from one of failure, in which students were never expected to achieve, to one of success, in which students achieved at similar levels to those across the state, meeting the benchmarks set for them as they are set for all students in Queensland. You can read his story, from his point of view, in his book Good Morning Mr Sarra, or a little in this extract available online.

How did Chris achieve this? He created a culture of high expectations. He had high expectations of his staff, and he required that we had high expectations of our students. We gave a consistent message of these expectations to all students across the community and throughout their school experience. Our students constantly heard that they had to be “strong and smart“, and we discussed what this meant over and over again, exploring it in different ways but applying it in all contexts of school life. “Strong” meant healthy in our bodies and our minds; it reminded students to eat as best they could and sleep as best they could and prepare themselves for learning. “Smart” meant being willing to learn, having a go, giving a consistent effort and working hard even when the work was challenging. The message was that students could succeed, could learn, could achieve, and could make good decisions for themselves and their families.

Maintaining high expectations required us as staff to challenge our ideas about our students, but more than that, it required our students to change their ideas about themselves. This is a pretty big ask. Out in the wider world, Indigenous Australians can be denigrated, dismissed, or simply made invisible, and hearing over and over again that you’ll never change, never grow, never learn, and never contribute – that you are useless and helpless – is a tough message to contradict. I still think every day about my former students at Cherbourg, and hope that we did enough to help them deflect that message with the one we gave them.

Learning to have high expectations of my students gave me a solid foundation for managing student learning and behaviour at all of the schools at which I worked following my very short stint at Cherbourg State School. It was the best lesson I ever received about teaching. I not only knew to have high expectations, I also knew how to communicate them. Having high expectations, though, takes a lot of effort, and the default position of everyone is laziness.

And I’m starting to notice a worrying trend in the world: I keep receiving the message that people don’t change. The message is that people don’t change their opinions, don’t change their beliefs, don’t grow up, don’t learn anything new. Worryingly, I occasionally receive this message from some of my pre-service teachers. And I object to this message, quite strongly. It’s lazy! People do change their opinions, their beliefs; people do mature, do learn new things and change as a result; people evolve. Just as energy drives change in the physical universe, surely learning drives change in the personal universe? If that’s not true, what is the point of teaching? What is the point of attending university?

The problem with the message that people don’t change is that it sets the expectation we have of others, and others have of us. If we are not expected to learn, to grow, to change, then we don’t have to, so we won’t. If our friends and families are not expected to change, what is the point in discussing anything with them? What is the point of thinking creatively, of solving problems, of investigating scientific ideas, of asking questions if no one is going to change anyway?

Carol Dweck has explored some of these issues in her research into implicit theories of intelligence. It reads a little bit like pop-psych, and is perhaps a little too black-or-white, but it goes like this: when students believe that intelligence, character and creative ability are static (they hold a “fixed mindset”), and they encounter a challenge, they withdraw their efforts, as they see no point in trying to do something that they obviously can’t do. Ultimately, they seek activities in which they can succeed and avoid activities in which they might fail. It’s a self-fulfilling prophecy.

The other side of the coin is that there are those who believe that intelligence, character and creative ability can and do change (they hold a “growth mindset”). Such people thrive not on success, but on challenge, and see failure as a springboard for further learning. Maria Popova describes the differences quite succinctly and illustrates them well on her blog Brain Pickings.

Further, Dweck contends that these “mindsets” are developed quite early on, and developed through the ways that children are praised in their early years. In general children praised for being “clever” go on to develop a fixed mindset, while children praised for having made an effort go on to develop a growth mindset. This should cause a pause for thought in both parents and teachers; Dweck’s suggestion is that our praise of even very young children can have a much greater and longer-lasting impact than we may have guessed. I’d still like to see more research on the topic, and replication from other researchers in different locations and cultures, but in the meantime we can consider how we might already have facilitated a fixed mindset in our society about people.

Further research by Dweck and her colleagues has found evidence that a fixed mindset causes us not to challenge stereotypes of our own and others, and has even challenged the notion that self-control is a limited resource. Perhaps some of the current feeling that people don’t change is reflective of a dominant (or at least, loudly communicated) fixed mindset in individuals in our community, and perhaps it is playing out in different ways. But for every racist rant on public transport that has gone unchallenged, another has been condemned by those around them.

Perhaps what Chris Sarra did at Cherbourg was to facilitate a change in the mindset of all of us; by requiring his teaching team and our students to hold high expectations of ourselves, he also set us up to embrace a growth mindset. And with that growth mindset, our students could see that they could achieve, they could learn, they could contribute, and maybe they could challenge some of the stereotypes given to them by others.

If the fixed mindset/growth mindset dichotomy has anything to it, and our expectations of others and ourselves lead to these mindsets, what we can do now is facilitate the a healthy growth mindset in our family, friends, colleagues and students. So, do something for me? Let’s start giving people the message that they can change their minds, their ideas; that they can grow and change and become better (or worse) if they want to. Let’s build a growth mindset, just like Chris Sarra and his teaching team accomplished at Cherbourg State School. Please go out there and have a conversation with someone today about something you changed your mind about. Next time you’re asked about your opinion and you don’t know very much on the topic, seek out more information. Next time you disagree with someone about something, ask them why they hold that opinion. See if your mind can change, or if you can change their mind, or if there’s a totally different solution altogether!

Let’s have high expectations of each other, rather than no expectations at all. Let’s grow and change and achieve together. And maybe, people will respond…

What do you think?

Solar stills: A demonstration of radiation, the water cycle, and physical changes

This post was inspired by Emily and Stephanie, who last week presented a lesson on the solar still to their peers.

See Pi’s solar still, behind him and to the right? It is a clear plastic dome.

Without clean water to drink, humans do not last very long at all. So when Pi is adrift on the Pacific Ocean, one of his first challenges (aside from cohabitation in a confined area with a tiger) is to find drinking water to sustain him (Martel, 2002). Thankfully, he discovers a set of solar stills on his boat, and promptly sets them up upon the sea water.

Two sets of instructions, with explanations, are available from the CSIRO and the Surfing Scientist (ABC). Both explanations are sufficient, but I don’t think they do the best job they could! Warning: I’m a primary school science teacher, so my explanations tend to be fairly basic. But that doesn’t mean they’re unsophisticated…

Setting up a solar still

You will need:

  • an ice cream container or bucket
  • a clean cup
  • a permanent marker
  • some tack
  • water
  • some plastic wrap or plastic sheeting
  • a weight (such as a marble, stone, or nut)
  • (optional) items to make your water “dirty”, such as salt*, food colouring*, and sand.
  • (optional) sticky tape

How to set it up:

  1. Mark off 10 ml, 20 ml, etc up the inside of the cup using a marker. Afterwards, wash the cup or make it clean without removing the permanent ink.
  2. Use the tack to fix the cup in the centre of the bucket. It should stay there even when water is added to the bucket.
  3. Pour water around the cup. You don’t need much; if you want a cup of water, use a cup of water. (There could be an investigation here for a curious student, into the relationship between the amount of water added to the bucket and the amount of water extracted from the still over time.)
  4. (Optional) If you want the water to be “dirty”, add those things that will make it dirty. I particularly like to use food colouring and/or salt, because it adds a further dimension to the explanation later.
  5. Cover the top of the bucket in plastic wrap. The edges should be sealed as best as possible. If the wrap isn’t sticking to the bucket, you might like to tape it down.
  6. Put the weight on top of the plastic wrap, over the top of the cup. It should force the plastic wrap into a sort of almost-flat cone, where the lowest point of the wrap is where the weight it.
  7. (Optional) Weigh the solar still using kitchen scales.
  8. Make a prediction. What do you think will happen? What will end up in the cup? Does the solar still weigh more, less, or just the same?
  9. Put your solar still in the sun. Wait a few hours. Make some observations. A particularly attentive child might like to take photos every half hour or so, and keep a record of how much water fills the cup.
  10. (Optional) Weigh the solar still using kitchen scales, again.
  11. (Optional, at the discretion of the parent, as I take no responsibility for this part!) Drink the water! Mmm, tastes fresh, right?
So what happens?

Evidence is about what we observe, without interpretation. This is what you should observe as your solar still sits in the sun:

After the solar still has been sitting in the sun for half an hour or so, it starts to look foggy inside.

Soon, the foggy bits on the plastic join and become droplets that stick to the plastic.

The droplets grow larger as they join and then travel down the plastic to its lowest point.

At the lowest point of the plastic, the droplets combine and then fall into the cup.

The droplets are transparent, as is the liquid in the cup.

Over time, the amount of liquid in the bucket goes down, but the amount of liquid in the cup goes up. If you weighed the solar still before and after sitting in the sun for a few hours, you *should* find that the whole thing weighs the same at the end as it did at the beginning.


The first part is really cool, and something I think many of us don’t fully appreciate. First, light from the sun (some visible to our eyes, some not)that has travelled an amazingly large distance at astonishing speeds hits the bucket. This transfer of light energy is called radiation. Light from the sun is absorbed by the bucket and everything within it, and the energy is transformed into kinetic energy by the molecules that make up the bucket and everything in it, causing them to vibrate faster. This is thermal energy, and when we touch the bucket it is transferred to our skin as heat.

People don’t often think about why it’s warmer in the sun than in the shade. But it’s because when the sun’s light hits you, it gives its energy to you and that extra energy is felt as heat. Isn’t that cool? It’s just the same when a strong lamp, such as one with a halogen bulb, shines on you. That’s not convection happening – hot air rises above cooler air, so it’s not the air bringing you the warmth - that’s the light energy that transforms when it is absorbed by your skin!

Next, the extra energy in the water causes some of it to evaporate. It turns into the gaseous form of water, which we call water vapour. Water vapour is invisible to our eyes; we just can’t see something that small. However, as it rises, the water vapour loses some energy and condenses; it clumps together, particularly when it hits the plastic wrap and gives off some of its energy to the plastic. We can see these clumps of condensed water. Initially the droplets are very very small and look like fog. Over time, they grow bigger because water is a particularly sticky molecule; it bonds easily with other molecules. So the droplets become bigger and bigger and heavier and heavier until they slide along the plastic wrap until they reach the lowest point, where they fall into the cup in the centre.

This is a similar process to the water cycle, in which water in its liquid form is evaporated by the sun’s rays, and rises as water vapour into the atmosphere. Along the way it loses energy and encounters particles of dust, etc, which cause it to clump so that we can see it, in the form of clouds. The droplets in the cloud become bigger and bigger and heavier and heavier, until eventually they can no longer be supported by the wind currents and other factors in the atmosphere, so they fall as precipitation, hitting the land and (eventually) returning to the rivers, lakes, seas and oceans, or else evaporating along the way. These phase changes are physical changes: the substance (water) changes in physical properties but not chemical make-up.

Finally, let’s look at how the liquid in the cup is different to the liquid in the bucket.

The liquid in the bucket, if you took the optional route of making it dirty, is a mixture of sand, salt, and food colouring. The sand is always visible and the food colouring changes the colour of the water, but the salt dissolves in the water and becomes invisible. Is this a physical change, where the two substances are mixed but do not react to make a new product, or a chemical change, where the two substances react to make at least one new product?

It’s difficult to argue that the salty water is just water with some salt in it; how can you tell, Miss Pezaro? How do you know? It is also difficult to convince students that adding food colouring to the water is merely a physical change; after all, Miss Pezaro, there’s been a colour change and you told us that was evidence for a chemical change (sometimes it is, kids, sometimes).

But the solar still separates this mixture, with what can be taste-tested as water sitting clear in the cup, and leaving behind the sand, salt and food colouring and just a small amount of water. It’s a nice way of showing primary-aged students that no new products were formed, and that food colouring and salt are merely dissolved into the water in the first place.

As for a chemical explanation for dissolving, we might leave that until we have some atomic ideas and a basic understanding of polarity, shall we?

Pi’s Still

The design of Pi’s still is a little bit different. His looks like an inverted plastic dome. Water from the ocean is evaporated and hits the plastic cover, where it condenses and collects, running down the sides into a channel that goes all the way around the still. The water runs down the little tube into the plastic bag, which I presume Pi can detach and drink from. The mechanism by which Pi’s still works is the same as ours; his simply has a different design. I wonder which is more efficient, or which works better in different conditions?  What other designs might work?

Pi’s still

Have you tried making a solar still before?

Is there anything you would improve about my explanation for the solar still?

What can I do about Climate Change? Reducing consumption

In my last post, I lamented the loss of individual empowerment to take action against climate change. In this post I’m going to talk about how I’ve gone about reducing my consumption of products.

When I teach about technology, I ask my students to consider the impacts and consequences of products throughout their life cycle: not just the use of their product, but its design, development and disposal as well. For example, when I buy a new shirt, I need to think about the time, energy and resources that went into its design, its production, and what will happen when I dispose of it. My new shirt was probably designed by someone in an office somewhere, then sewn together by someone in a south east Asian country who was comparatively underpaid and overworked, using materials or fabrics that came from another factory with workers in similar conditions, then it was transported by ship across the ocean, packaged up in a warehouse in Melbourne or Sydney, then sent to the store, where I bought it. I’ll wear it until it’s looking a little bit old and worn, and then I’ll either donate it (so that someone else can use it), cut it up for dusters, or throw it in the bin, where eventually it ends up in a dump. It’ll take 5 – 10 years to break down, depending on the conditions its in. I paid $30 for the shirt, but it costs a lot more in time, energy and resources over the life of the product, and at each stage, carbon dioxide and other greenhouse gases may be emitted into our atmosphere as pollution. Without a carbon price, I’m not actually paying for the pollution attributed to my shirt, so essentially, I’m polluting without consequence. (I’m not saying that if a carbon price does come in, we should consume as much as we like though. The mechanism of the carbon price is that particular items cost more, encouraging us to reduce our consumption anyway.)

So one of the things I can do to minimise the amount of carbon dioxide and other greenhouse gases into the atmosphere, and thus mitigate climate change, is to reduce my consumption of products. Here’s how I do that.

1. I don’t go shopping unless I actually need something.

This will probably horrify a lot of people out there who are committed to shopping as a habitual pastime, but I actually don’t go shopping very often at all. I’ve been twice since Christmas (nearly 4 months), and both times with goals in mind. I really, really, really like new and pretty and shiny things, and I know that when I see them, it’s hard not to want to buy them. So I take the temptation away. I just don’t go shopping. There are lots of other things I find more fun anyway. I try to have experiences rather than things, like going to the park or a cafe to read a book or do a cryptic crossword. I catch up with friends, or go to the beach, or attend plays or shows, or visit the museum or art gallery. Not shopping should save me money in theory, but it doesn’t because I spend it on experiences instead! And those experiences (usually) have a much smaller impact on the environment than constant consumption does.

2. I don’t buy anything unless I actually need it; it must meet a useful purpose.

Don’t really need it? Don’t buy it. You just make it harder for people who want to buy you a unique gift for your birthday anyway! Stuff just sits around gathering dust. I’m not a “stuff” kind of person. Books are a general exception, and we’ll talk about that some more in a few paragraphs.

I have all the things I need to live and to make living worthwhile already. I don’t need the extra basket to hold the toilet paper or the stickers or more than one handbag (two at the outside). I don’t need a second toiletries bag or fifteen towels or a third set of bed sheets. I have enough.

3. I buy clothes which suit me and will last through trends, rather than fashion.

Look. Look. No one who has ever met me is surprised about this. I am the last person who should give fashion advice to anyone. But I do know that because I buy items that are stylish rather than fashionable, they last longer than clothes that conform to the latest trend. Trendy clothes look awful after a couple of months (I mean, c’mon, who on Earth thought the peplum was a good idea even for the one week it was in? Honestly) but my clothes last me  a couple of seasons. And as I’ve already said, I prefer to spend my money on fun experiences instead.

4. I buy digital when I can.

I am so, so glad that the world has now brought us digital music and video. I no longer need to flick through a million CDs (Aaron has his alphabetised, anyway) or DVDs to find the one I want. Everything I want to watch or listen to is in a library on my computer. Nowadays, I can even rent movies or TV shows for less than it was cost in petrol to go and pick it up from a store, and I can listen to music by streaming the radio or using a streaming service, legally (I also never pirate anything. That’s a different post).

As for books, I move between the book app on my tablet and real paper books. Generally these days, unless it’s a book by my favourite authors, I buy ebooks. I already own plenty of books, and I reread them often. Books I don’t reread get donated. Easy.

5. I don’t accept free stuff.

“There’s no such thing as a free lunch,” I’ve heard, and I think it’s true. Hey, you might really like and use that pen that’s also a ruler and a highlighter that you received from that publisher at that conference in your conference bag (along with a million pieces of paper advertising things you also don’t need), and you might not have paid for it, but it wasn’t free. The publisher paid for it, paid to put it in your bag, put their name in your head and then one day you’ll throw it away and it will sit in a dump for 20 years. That’s not free, that’s just convenient, for you and the publisher.

I didn’t need it, I didn’t ask for it, so I don’t want it. They never put really valuable or useful things in those bags anyway!

Any other ideas for how I could reduce my consumption?

What can I do about Climate Change?

I first heard about climate change back in 2007, when I attended the CSIRO Scientists in Schools Symposium on Energy and Climate Change. I was flabbergasted by the staggering evidence and backing presented to attendees that the climate was changing, that we as a species had driven it, but mostly I was amazed that I had never, ever heard of it before. I had a Science degree, I paid attention to the news, I’d studied Biology in high school – how had I never heard of global warming before?

I was motivated and inspired and following the two day symposium I made a few changes in my lifestyle and activities to try to do what I could to mitigate climate change:

  • I recycled, and chose products where packaging was recyclable;
  • I reduced my consumption by buying less clothes, products and throwaway items (the positive consequence of this was a saving in funds too!);
  • I bought products that were reusable, such as a keep-cup and a metal water bottle;
  • I donated unwanted items rather than throwing them in the bin;
  • I walked more and tried to drive less;
  • I turned off electrical devices overnight (this used to drive my housemates nuts);
  • I chose the renewable power option from our electricity provider (this also annoyed my housemates, so I paid the extra cost myself);
  • I talked about the issue with my family, friends, colleagues and students; and
  • I developed sustainability and environmental science units to teach at my school.

Climate change was also almost certainly why I became interested in the topic of my PhD thesis.

But worrying about big issues wears us down, and over the years I stopped asking others to do these things, too. Some habits remained. But nobody else seemed to be doing anything, and the fight is tiring. Politicians were still arguing about whether or not it was actually occurring, and the businesses who profit from the status quo, well, maintained the status quo. The few deniers out there with a lot of money made a big fuss – they’re still making a fuss – and exerted influence where they could, their voices louder than the environmentalists’. Nothing major changed. Meanwhile, the problem got bigger, the projected consequences are greater – devastating weather and climate events, ocean acidification and the loss of our reefs, sea level rise, mass extinctions, loss of biodiversity, less clean water and food available for all species, climate refugees – and the time frame in which the problem must be addressed shortens. And I lost hope.

In politicising the problem, we’ve also shifted it to the responsibility of our representatives. We’ve disempowered individuals from doing anything other than voting. And lately, it seems that even voting isn’t worthwhile. In general, people find change confronting and threatening, and it’s easier to accept the soothing promises of powerful corporations, individuals and political parties  that this isn’t really happening and we can just keep going as we are. And now in our parliament, those actions that have been enacted to reduce the carbon dioxide output of major polluters of greenhouse gases are being repealed by those whose motivation is questionable.

However, in my own work, teaching undergraduate students at university, I have the privilege of talking to young Australians and international students about science, often. And climate change does come up in conversation. Overwhelmingly, students accept the position that climate change is anthropogenic, mostly on the basis of scientific authority. However, when asked what they do about it for themselves, the response is often a shrug or smile accompanied by the statement “not much”. Many of my students don’t seem to see themselves as agents of change; that responsibility is left to those in powerful positions. But teachers are agents of change, and education ultimately brings about progress. So I have a responsibility, to enact changes myself, to model changes for others, to help others adapt to changes and to empower those around me – family, friends, colleagues and students – to do what they can as individuals.

So I’ve decided to bring about some changes in my life, again. Some of the habits I have are good – for example, taking public transport every day and using containers for my lunch rather than throw-away packaging – and others not-so-good. And along the way, I’ll write some posts about these changes, in the hopes that those around me might choose to make some changes too.

What changes do you believe that we as individuals can make to help mitigate and adapt to climate change?

What would be a helpful resource for you and your family, friends, colleagues or students for bringing about changes?