Category Archives: science outreach

Ocean acidification explained with dry ice

Dear imaginary readers,

It took ages for me to write a post as I am about to embark in a very exciting new adventure in the very near future.

I wanted to write this post straight after I was back from Into the blue in Manchester last October, but my worst enemy, the God of Postponing won the battle.

If you remember I was there with the Environmental Chemistry Group of the Royal Society of Chemistry working as a volunteer to introduce the public to the real problems the environmental chemists work on.

We had three stalls with different “hands on” interactive activities for kids (even though adults seemed to enjoy as well).

The first and the second were about environmental pollution, with a tray full of soil and small pieces of plastic dispersed in it and simple nitrates and phosphates testing kits.

into the blue 2

The real queen of the activities we proposed was the ocean acidification demonstration. It does involve smoke and colour changes so it does automatically attract the public attention.

In the rest of the article you can find the procedure, materials and adaptations you can use to realize the experiments in secondary schools, lab or even in the streets, as we did!

First of all we assessed what the audit knows about pH, asking questions and showing a pH colour scale. Then we encourage people to test different thing like drinking water, “fake” pre-made ocean water (pH about 8.2, adjusted with NaOH), coke, orange juice, milk and soap solution with bromothymol blue, litmus paper or any other pH indicator.

Ask the spectators if they know where seawater fits in on the spectrum. Explain that pH is measured on a logarithmic scale like earthquakes and a small change in pH from 8.2 to 8.1 corresponds to an increase in acidity of about 30%.

For this activity, the audience should understand that when humans release carbon dioxide into the atmosphere by burning fossil fuels, some of the carbon dioxide is absorbed by the ocean. This changes the chemistry of seawater making it more acidic. About one third of the carbon dioxide released into the atmosphere over the past 200 years has been taken up by the ocean.

Then we started to explain why ocean acidification is a current and future problem. The average coastal ocean pH is 8.2, but it is changing because of the addition of carbon dioxide to the atmosphere and the subsequent absorption of that carbon dioxide into the ocean. About 30% of the carbon dioxide produced daily is absorbed by the ocean. The pH of the ocean has decreased 0.1 in the last century; it is becoming more acidic (less basic). Some of the organisms at greatest risk include larva and shell-forming animals at the base of the food web that provide food for larger species. Organisms faced with the stress of ocean acidification can migrate, acclimate or go extinct and values of 7.8 are expected by 2100 for the average ocean water, representing a doubling of acidity. Additional stressors that increase the impact include temperature increase and habitat loss.

Then you show the spectators the dry ice in a watch glass pointing out that is the solid form of CO2 and that is changing to a gas (sublimation) at room temperature, so its temperature is about -78 C so they should never touch it with bare hands. When it is added to water it rapidly changes to the gas form and some of this gas becomes dissolved in the water.

We then added enough dry ice to a conical flask containing the “ocean water” and bromothymol blue and the solution will turn progressively yellow as the pH decreases because of the formation of carbonic acid that acidifies the solution.

Because of the quick reaction and the big temperature difference between the “sea water” and the dry ice there will be quite a bit of what looks like smoke or fog billow away from the conical flask (it is actually vapour). The kids will go really excited (some of them even scared) and you will definitely get some “oooooooooooooooh”.



When the reaction has finished and the spectators have regained their concentration, we tried to recap what they saw and why it matters to the ocean’s environment. Adding carbon dioxide to water makes it more acidic or less basic. This is what is happening to the ocean. Humans add carbon dioxide to the atmosphere by burning fossil fuels (driving cars, creating electricity, etc), deforestation, and in many other ways. The ocean then absorbs some of what gets emitted into the atmosphere, sometimes we say that the ocean acts as a “sink” for carbon dioxide. This effect is worsened by the global warming of the planet. The change in the chemical average composition of the ocean’s water, have consequences on many marine creatures, such as shell forming organisms such a corals, bivalves (clams, mussels and oysters) and pteropods (free swimming snails) that are sensitive to changes in pH.

If you want to do this demo as part of a wider lesson in schools, you can add a detailed explanation of the different reactions the CO2 gives in different environments and related demonstrations (acidic rain, weathering of rocks, cave formation)

For the ocean acidification the chemical reaction is the following.

CO2 + H2O      →        H2CO3

As shown in the chemical reaction scheme, when carbon dioxide (CO2) dissolves in seawater, it creates carbonic acid, which releases bicarbonate ions (HCO3-) and hydrogen (H+) ions into the water. The hydrogen ions make the seawater more acidic (lowering its pH). In addition, some of the hydrogen ions react with carbonate ions (CO3=) already in the seawater to create more bicarbonate. This reduces the amount of carbonate (an important mineral for building shells) dissolved in the seawater. The impacts of ocean acidification and lower carbonate ion concentrations on marine ecosystems include reduced growth of organisms that form calcareous skeletons or shells.

Ocean acidification and global warming are relegated to the science fiction shelves by one of the more powerful politician of the world, at a point in the life of our planet when the consequences of the increase of CO2 released into the atmosphere are about to spiral up culminating in a very hostile environment for humans and every other living thing.

For this reason is more important than ever to engage in outreach activities trying to explain to as much person as possible that our choices have a very big and dangerous impact on the place where we live, and that it is important to act on a personal and a political basis.

Time is now!

“I think that once people understand the great risks that climate change poses, they will naturally want to choose products and services that cause little or no emissions of greenhouse gases, which means ‘low-carbon consumption.’ This will apply across the board, including electricity, heating, transport and food.” Nicholas Stern, IG Patel Professor of Economics and Government, Chairman of the Grantham Research Institute on Climate Change and the Environment and Head of the India Observatory at the London School of Economics.

Have a lovely end of summer everyone, but always try to be conscious! Hasta la vista




Soapbox Science in Brighton is looking for volunteers


Have you ever encountered a lady dressed wearing a lab coat and talking about scientific staff standing on a soapbox in the middle of your local high street?

If your answer is yes, chances are you took part in a Soapbox Science event. Soapbox Science is a fairly recent (everything started in 2011) outreach platform for promoting female scientists and the work they do.

The two co-founders of this fantastic series of events are the ecologist Nathalie Pettorelli, who currently works as researcher at the London zoo, and the biologist Serian Sumner, member of the Eusocial Insect Research Group, at the University College London.

Public areas are transformed into an arena for public learning and scientific debate, following the format of London Hyde Park’s Speaker’s Corner, which is an historical place for public debate.

It is all about direct, hands on science communication:

“What happens if you put a few scientists on soapboxes on a busy street? We’ll tell you what happens: People who don’t usually think about science get to hear about it first hand, from scientists who don’t necessarily have shaggy beards and odd matching shoes, but who do know how to share their passion for experimentation, discovery and innovation. Soapbox Science is a grass-roots approach to taking science to the public. No fancy festivals; no stuffy lecture-theatres: just some of the UK’s top women in science, a couple of silly props, a dash of summer showers, and lots of unsuspecting tourists. It’s street theatre with a difference. And we aim to make a difference!”

Sumner & Pettorelli, Soapbox Science Founders, July 2012.


Someone may see the fact that the speakers have to meet only the requirement of being a woman, other than being a genuine scientist, as discriminatory. I would rather call it a positive discrimination, a way to put ourselves in the first line showing to the public what we can do and that we actually do it, showing off the importance of women in STEM. Many people struggle to convey on the fact that there is a problem of imbalance and stereotypes preventing women to occupy the decisional places of the ladder, but the House of Common Science and Technology Committee report “Women in Scientific Careers” 2014 states that only the 17 % of academics in STEM are female, even though the number of women enrolling scientific courses is increasing.

One of the most important Soapbox Science event is going to take place in Brighton on Saturday 29th July 2017, 1-4pm, on Brighton Seafront. The key speakers of the day will be:

  • Ms Pollie Barden (@polliepi), University of Sussex “Firefly – A game of dark intentions”
  • Professor Claudia Eberlein (@ClaudiaPhysics), University of Sussex “The Quantum Vacuum – Something from Nothing?”
  • Dr Samantha Furfari (@SamFurfari), University of Sussex “Coordination Chemistry: What is it and what can it be used for?”
  • Dr Orode Aniejurengho (@orodeUVA), Tissue Click Ltd. “Using helpful viruses as medicine to fight bacterial infections”
  • Ms Madeleine Conaghan (@maddyconaghan), University of Brighton “Invent, Design and Create products that solve problems”
  • Dr Charlotte Clarke (@astronomnomy), Brighton and Sussex Medical School “Why astrophysics and neuroscience look the same to a rubber duck”
  • Miss Millie Watts (@GeoMillie), University of Southampton “Will climate change cause more tsunamis in the UK?”
  • Professor Louise Serpell (@serpelllab), University of Sussex “Changing the shape of proteins: from spiders to Alzheimer’s disease”
  • Dr Ruth Murrell-Lagnado (@RuthMurL), University of Sussex “Excitable cells and Drugs”
  • Dr Dawn Scott, University of Brighton “City nights with the wild furry urbanites: do you know what happens in your garden after dark?”
  • Miss Taniya Parikh (@taniyaaaaaaa), University of Portsmouth “A galactic tale: from a cloud of gas and dust to billions of stars”
  • Ms Sonali Mohapatra (@Sonali_Mohapatr), University of Sussex “Gravity and Blackholes: Linking Fantasy and Reality”

For this event Soapbosx Science is still looking for volunteers helping out rounding up the public, chatting to them informally about science, supporting the speakers by managing props and helping to calm any pre-box nerves as well as handing out Soapbox goodies to lucky audience members. But perhaps the most important role of the volunteers is gathering data so we can effectively monitor the success of the event: volunteers carry out the bulk of our streamlined evaluation process, through interviews, observations and counting footfall.


For more practical information and application click here.