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CW8:Students should be able to investigate the reactions between acids and bases; use indicators and pH scale.

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nature of science:

Nos1, Nos3, Nos4 ,Nos6. Nos7, Nos10

other strands

CW7 and CW9

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students should see:

its a scientific journal

published in the last 5 years

contains facts

references at end

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The ‘Impossible’ benefits of Salt Lamps – Science In Our Lives

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students should see:

its by a newpaper

published date

no facts

no quotes

no references

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Himalayan salt lamp: allergen trapper, insomnia cure or just a fancy light?

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It looks banging on a bookcase and you can even get one in the shape of a penguin. But I am yet to feel the health benefits of these salty blocks

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Acid rain can harm the environment and your health. Learn about what causes it and how to prevent it.

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Lakes throughout North America were heavily affected by acid rain (Credit: Getty Images)

Acid rain went from being a pollution disaster to an environmental success story. How did scientists manage to prove that acid rain existed, and find a way to stop it?

A group of kids canoeing in Canada's Killarney Provincial Park are paddling across a serene and unnaturally turquoise lake. It's a hot sunny day, and a thirsty boy dips an aluminium cooking pot into the water to refill his fellow canoeist's canteens. In a momentary lapse of concentration, the pot slips from his grasp. As it sinks underwater beyond reach, what's incredible is that it's visible all the way down to the lake floor some 50ft (15.2m) below.

It's the mid-1980s. One of the kid canoeists is me, and there's an unfortunate explanation for this water clarity. This lake, near the nickel and copper smelters of the town of Sudbury, Ontario, has been radically altered by acid rain. Almost every living thing in the water - like the tiny algae that would normally block light from reaching the depths - has gone, leaving the water here and in lakes across the region a beautiful but eerily lifeless aquamarine.

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Fast forward to 2019 and another set of lakes in a remote corner of north-west Ontario. Biologist Cyndy Desjardins is sipping coffee at breakfast following a nocturnal boat trip at the International Institute for Sustainable Development's Experimental Lakes Area (IISD-ELA). Smiling but sleepy, she spent much of the night working in nearly pitch-dark conditions, surveying for tiny monster-like creatures: freshwater opossum shrimp called Mysis relicta. Desjardins is part of a team attempting to close the loop on an acid rain experiment that began in the 1970s.

The freshwater shrimp Mysis relicta suffers in lakes that have been acidified (Credit: Andrew Milling)

At its worst, acid rain stripped forests bare in Europe, wiped lakes clear of life in parts of Canada and the US, and harmed human health and crops in China where the problem persists. Looking back today, there is little argument that the cause was sulphur dioxide and nitrogen oxides emitted by fossil fuel combustion by cars and industrial facilities like smelters and coal-burning utilities. When combined with water and oxygen in the atmosphere, these air pollutants chemically transform into sulphuric and nitric acid. Acidic droplets in clouds then fall as rain, snow or hail.

We know this now. But for a long time, acid rain was a puzzle. In 1963, as part of a long-term ecosystem study that is still ongoing today, Gene Likens collected a sample of rain at the Hubbard Brook Experimental Forest in New Hampshire's White Mountains. That sample was "about a hundred times more acidic than we thought it should be", says Likens, now emeritus professor in ecology at the Cary Institute of Ecosystem Sciences in Millbrook, New York. His discovery back in 1963, on the heels of work dating back to 1872 and even earlier, set the collective wheels in motion to raise awareness and isolate the cause of acid rain. Not just in North America, but across the industrialised world.

Scientists would protectively suit up like Darth Vader, make a sulphuric acid solution and use the boat propeller to mix the cocktail across the whole lake.

Other crucial evidence that led to action on acid rain - on both sides of the Canada-US border - came from experiments at north-west Ontario's Experimental Lakes Area (ELA). Its soft-water lakes were far enough from sources of pollution that they had escaped the effects of acid rain, acting as a control.

Unlike many lakes, composition of the healthy ecosystem in the ELA was well documented. That enabled scientists like David Schindler, then an ELA senior scientist and now emeritus professor at the University of Alberta, Canada, to add acid experimentally to one lake and see how the ecosystem responded. ELA scientists would protectively suit up like Darth Vader, make a sulphuric acid solution and use the boat propeller to mix the cocktail across one of the lakes.

Industrial pollution played a huge role in acid rain in the latter half of the 20th Century, but it was decades before it was recognised in policy (Credit: Getty Images)

Over seven years beginning in 1976, they lowered the pH of one lake, number 223, from 6.8 (close to neutral) to 5.0 (slightly acidic). Lab studies had suggested a pH of 5.0 would not harm fish. But in the lake 223 experiment, long before it reached 5.0, it did. By the time the pH reached 5.6, most of the lake trout's preferred food - tiny organisms that require calcium to form exoskeletons - had died as acidified waters dissolved their protective coats.

"Lake trout stopped reproducing not because they were toxified by the acid, but because they were starving to death," says Schindler.

Lake trout stopped reproducing not because they were toxified by the acid, but because they were starving to death - David Schindler

Freshwater microbiologist Carol Kelly arrived at ELA in 1978 just as acid rain experiments got underway. She became curious about a particular puzzle the lake acidification experiments had stumbled on. Her colleagues had carefully calculated the quantity of acid needed to drop lake 223's pH to 5.0 - a simple calculation a high-school student could do. But out in the lake it became clear that their calculations were way out of whack.

"I had given the crew orders to take the lake down to a given pH and then add enough acid to hold it there," says Schindler. Part way through the season, the crew reported that they were running out of acid. Acidifying the lake took way more than they thought, says Kelly. "The question became, where is it going?" she says.

Lakes in Ontario were affected by acid rain for decades, with concern rising for them in the 1980s (Credit: Getty Images)

Kelly and colleagues set to work to find out, and discovered that alkali-producing microbes were capable of buffering some of the acidity, helping the lake chemistry to recover. That acid could be neutralised by bacteria living in every lake was a controversial finding at the time.

"People didn't believe it," Kelly says. But she continued to find out just how much acid microbes could neutralise, travelling elsewhere in Canada, the US and Norway to lakes that had been acidified atmospherically, to test this natural recovery ability. The discovery that acid-neutralising bugs exist in the sediment in lots of lakes, not just at the ELA, suggested that lakes could recover if the pollution causing the acid rain were eliminated.

Compelling photographs of starving fish from lake 223, combined with efforts by environmental groups like the Canadian Coalition on Acid Rain, helped persuade policymakers - eventually - to legislate more rigorous air quality standards.

But acid rain research at ELA almost didn't happen at all. Founded to address the issue of excess nutrients contaminating lakes, work that had already drawn far-reaching conclusions by the early 1970s, Canada's federal government was poised to pull the plug on the research station. At a presentation to federal fisheries officials, Schindler says that despite considerable evidence from the US, one official accused him of inventing the idea of acid rain just to save the ELA.

Scientists began pinpointing culprits and journalists covered the problem through the 1970s and 1980s, but some people working in industry were doing their best to obfuscate, sow doubt and delay action.

Acid rain stripped trees bare of leaves in areas of Europe affected by industrial pollution (Credit: Getty Images)

"There were lots of deniers of acid rain," says Likens. At the time, Likens remembers giving public lectures on the topic. On occasion someone would stand up, rudely interrupt him, and say they didn't believe in acid rain. "I would often respond by saying, 'Well, have you ever collected a sample of rain and analysed it?' They would say 'No' and I would say, 'Well try it some time.'"

Like with climate change, says Likens, there were many big, powerful, wealthy people involved with vested interests. From its discovery in 1963 to passage of the Clean Air Act in 1990, legislative action on acid rain took 27 years.

Over that time, many a cross-border argument erupted. "The first international altercation over acid rain was the US accusing Canada of acidifying lakes in the boundary waters," says Schindler. The squabble was over a small coal-burning power plant in Atikokan, Ontario, that US representatives claimed was sending acid rain south of the border. Schindler attended a meeting in Minneapolis, Minnesota, along with other Canadian scientists and their US counterparts.

Acid rain was at one time the number one Canada-US bilateral issue - Ad&egrave;le Hurley

"When all the data were on the table, it was clear that the little bit of sulphur from Atikokan was inconsequential to boundary waters," Schindler says. At the same meeting, scientists examined net international flows of emissions. It became obvious, says Schindler, that the US, particularly the Ohio Valley and industrial areas of Pennsylvania and New England, were producing more than half the acid rain that collected in Canadian lakes.

The blame game continued, and acid rain "was at one time the number one Canada-US bilateral issue", said Adèle Hurley in a speech reflecting on decades of work with the Canadian Coalition on Acid Rain, which she co-founded in 1981. The coalition was eventually disbanded following amendments to the US Clean Air Act in November 1990, establishment of the Acid Rain Program, and parallel action on the Canadian side.

Adding large quantities of alkaline substances helped to neutralise lakes affected by acid rain (Credit: Getty Images)

A half-century after those early experiments, lake 223 in the ELA is no longer acidic, the acid-eating microbes having done their job. Lake chemistry has returned to its pre-experimental state. Biological recovery, however, has lagged behind. Freshwater opossum shrimp are found in healthy numbers in untouched control lakes. But in 223, they are still missing. So, Desjardins and others are investigating whether reintroductions of the opossum shrimp - 10,000 painstakingly counted at a time - might jumpstart biological recovery of the ecosystem.

Early signs look positive. Remote operated underwater vehicles searching for evidence of these mini-monsters of the deep have spotted just two Mysis shrimp swimming freely in lakes thus far, but it suggests that all that midnight catching and counting in the dark is not in vain - these tiny missing links in the ecosystem eroded by acid rain may be coming back.

Broader recovery, in lakes across North America, happened because acid rain was tackled at its source.

Compared with 1990 levels, sulphate ions in the atmosphere have dropped considerably, reduced to almost negligible levels at former hotspots. But the problem has not disappeared altogether. Nitrates from sources like agriculturally emitted ammonia released from fertilisers and livestock feed remain a contributor to nitric acid precipitation. And there is concern that acid rain - from both sulphur and nitrogen - is an increasing problem in Asia.

There are no simple solutions to complex environmental problems. But are there parallels between efforts to curb acid rain and strategies for action on climate change? Schindler does see similarities in the procrastination tactics employed by industry. "Seed enough doubt, and pay for enough political campaigns, and you can delay action," he says. "That sounds pretty crass but if you look closely, that's how most environmental problems are addressed, and climate is no exception."

Despite this, emissions reductions have been a huge success story in tackling acid rain, says Likens. But further reductions, especially on nitrogen oxides, are needed. The current US president is proposing to cut back regulations on emissions. If this happens, says Likens, recovering lakes in places like the Adirondack Mountains in north eastern New York would be particularly vulnerable, their acid-neutralising capacity already weakened.

Policies to reduce acid rain in the US and Canada have been largely effective, allowing lakes to begin recovery (Credit: Getty Images)

Tackling acid rain in North America required actions in two neighbouring countries. But for climate change, the challenge is broader and solutions must be global. Nevertheless, the two issues do share similarities. Both, says Hurley, require cutting-edge science, media coverage and finding common ground, building coalitions between opposing parties.

In the fight Hurley helped to lead against acid rain, this meant talking to coal workers at sportsmen's shows, engaging them in conversations about clean water for fishing salmon, and going for walks in war cemeteries where acidity was ruining the limestone of gravestones.

Though aspects of its legacy remain, solutions to the acid rain problem moved forward, in North America at least, because it became a non-partisan issue. Hurley reflects that "a broad spectrum of people came to believe that it was important to protect natural resources - our forests, our northern lakes and the fish they contain - resources that belong to everyone".

If anything can be learned from the acid rain story, it's that the same breadth of support and dismantling of partisanship is necessary for protecting the Earth's climate.

Lesley Evans Ogden is on Twitter @ljevanso

If you liked this story, sign up for the weekly bbc.com features newsletter, called "The Essential List". A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.

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The bittersweet story of how we stopped acid rain

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Acid rain went from being a pollution disaster to an environmental success story. How did scientists manage to prove that acid rain existed, and find a way to stop it?

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Acid rain describes any form of precipitation that contains high levels of nitric and sulfuric acids. It can also occur in the form of snow, fog, and tiny bits of dry material that settle to Earth. Normal rain is slightly acidic, with a pH of 5.6, while acid rain generally has a pH between 4.2 and 4.4.

Causes of acid rain

Rotting vegetation and erupting volcanoes release some chemicals that can cause acid rain, but most acid rain is a product of human activities. The biggest sources are coal-burning power plants, factories, and automobiles.

When humans burn fossil fuels, sulfur dioxide (SO ₂) and nitrogen oxides (NO x) are released into the atmosphere. Those air pollutants react with water, oxygen, and other substances to form airborne sulfuric and nitric acid. Winds may spread these acidic compounds through the atmosphere and over hundreds of miles. When acid rain reaches Earth, it flows across the surface in runoff water, enters water systems, and sinks into the soil.

Effects of acid rain

Sulfur dioxide and nitrogen oxides are not primary greenhouse gases that contribute to global warming, one of the main effects of climate change; in fact, sulfur dioxide has a cooling effect on the atmosphere. But nitrogen oxides contribute to the formation of ground-level ozone, a major pollutant that can be harmful to people. Both gases cause environmental and health concerns because they can spread easily via air pollution and acid rain.

Acid rain has many ecological effects, especially on lakes, streams, wetlands, and other aquatic environments. Acid rain makes such waters more acidic, which results in more aluminum absorption from soil, which is carried into lakes and streams. That combination makes waters toxic to crayfish, clams, fish, and other aquatic animals. ( Learn more about the effects of water pollution.)

Some species can tolerate acidic waters better than others. However, in an interconnected ecosystem, what affects some species eventually affects many more throughout the food chain, including non-aquatic species such as birds.

Acid rain and fog also damage forests, especially those at higher elevations. The acid deposits rob the soil of essential nutrients such as calcium and cause aluminum to be released in the soil, which makes it hard for trees to take up water. Trees' leaves and needles are also harmed by acids.

The effects of acid rain, combined with other environmental stressors, leave trees and plants less healthy, more vulnerable to cold temperatures, insects, and disease. The pollutants may also inhibit trees' ability to reproduce. Some soils are better able to neutralize acids than others. But in areas where the soil's "buffering capacity" is low, such as parts of the U.S. Northeast, the harmful effects of acid rain are much greater.

Acid deposits damage physical structures such as limestone buildings and cars. And when it takes the form of inhalable fog, acid precipitation can cause health problems including eye irritation and asthma.

What can be done?

The only way to fight acid rain is by curbing the release of the pollutants that cause it. This means burning fewer fossil fuels and setting air-quality standards.

In the U.S., the Clean Air Act of 1990 targeted acid rain, putting in place pollution limits that helped cut sulfur dioxide emissions 88 percent between 1990 and 2017. Air-quality standards have also driven U.S. emissions of nitrogen dioxide down 50 percent in the same time period. These trends have helped red spruce forests in New England and some fish populations, for example, recover from acid rain damage. But recovery takes time, and soils in the northeastern U.S. and eastern Canada have only recently shown signs of stabilizing nutrients.

Acid rain problems will persist as long as fossil fuel use does, and countries such as China that have relied heavily on coal for electricity and steel production are grappling with those effects. One study found that acid rain in China may have even contributed to a deadly 2009 landslide. China is implementing controls for sulfur dioxide emissions, which have fallen 75 percent since 2007 -but India's have increased by half.

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The fossil fuels that humans burn for energy can come back to haunt us as acid rain.

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This will be document 5 for students to analyses in lesson 2.

This is a report based on acid rain and its ecological consequences. this report focus on acids rain, what causes it, what's it effects are and how we can control it. these are the main concepts of lesson 2. relating the knowledge from lesson 1 to the real world. student will also be analysing this document using many key skills. this will be a good source.

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this will be document 6 for students to analyse. This journal is based on the problems of acid rain. it focuses on a different preceptive from the other journal/articles. it looks more at the politic impacts and how atmospherics pressure causes and transports acid rain. this gives students a chance to see different opinions surrounding a topic. student should identify this as a reliable source.

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conduct: to preform an activity.

investigate: observe, study, or make a detailed and systematic

examination, in order to establish facts and reach new conclusions.

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Reaction Energy Profiles activation energy exothermic endothermic reactions catalysed uncatalysed reactions gcse notes KS4 science igcse O level chemistry revision

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Why are there energy changes when a chemical reaction takes place? Do physical state changes involve energy changes? Exothermic energy changes and endothermic energy changes in chemical reactions are described, and exothermic reactions and endothermic reactions are discussed in terms of bond energies - including calculations of energy transfers for GCSE/IGCSE and basic stuff for GCE Advanced Level AS students. Methods of obtained vales for energy changes in chemical reactions are described and how to do the calculations based on calorimeter experiment results. Also discussed are activation energies, reaction profiles, catalysts.

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Understanding Science - How science REALLY works...

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The stereotypical image of a scientist is not a very social one: a geeky guy, isolated in a windowless basement lab, strictly following the rules of THE Scientific Method, until he finally makes a great discovery. No collaborators, no communication, no diversity. What's wrong with this picture? Well, several things:

1. First, as discussed in How science works, there is no single scientific method that can be blindly followed. The process of science is flexible and may take many possible paths.

2. Second, science is done by unique individuals - not by automated robots coldly following a routine without motivation, ambition, or creativity. Scientists are people too! Many of them care passionately about their work, and many of them are intensely creative. Their personalities, backgrounds, and goals are highly diverse.

3. And finally, science is embedded within a global scientific community. This community provides cultural norms, expectations, and accumulated knowledge, which are essential to the expansion of scientific knowledge.

In opposition to its stereotype, science much more typically works something like this: After reading up on the recent work of other scientists studying animal behavior, a scientist in Brazil gets an idea for a new bird song experiment while playing a word game with her kids. She calls a colleague in Canada to discuss the idea and to find out where she can get the recording software she will need for the experiment. She then recruits a few students and a visiting researcher from China to work on the project, and they apply for funding. After they complete the study, the team writes up the work and submits it to a journal for publication. The journal sends it out to three different scientists for review: one in Japan, one in the U.S., and one in the U.K. The reviewers like the study but suggest some changes to improve the statistical analysis. The team makes the changes and the paper is published several months later. A graduate student in France reads the paper with his lab group, emails the Brazilian researcher to learn more about her experimental procedures, and comes up with a follow-up experiment. He recruits another graduate student and a professor to work on the project with him ... and so on. Compared to its stereotype, real science is more complex - but also more human.

Scientists do spend time working alone - in the field, in the lab, or at the computer - but most also collaborate on research with others. And, of course, scientists don't just do research. Most scientific work also involves reviewing other scientists' articles for journals, teaching, mentoring graduate students and younger scientists, speaking at conferences, and participating in scientific societies. So the job of being a scientist involves lots more than disappearing into a windowless lab and running an endless series of experiments!

Here we'll discuss how individual scientists interact with the rest of the scientific community and how this benefits the progress of science. You can investigate:

Or just click the Next button to dive right in!

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The social side of science: A human and community endeavor - Understanding Science

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The stereotypical image of a scientist is not a very social one: a geeky guy, isolated in a windowless basement lab, strictly following the rules of THE Scientific Method, until he finally makes a great discovery. No collaborators, no communication, no diversity. What's wrong with this picture?

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Young Scientists Journal: Inspiring Science Enthusiasts

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Young Scientists Journal - Peer-reviewed scientific research by young people across the globe.

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links to JC skills and important principles 

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links to JC skills and important principles 

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Links to JC key skills and important principles

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references:

Regina Kelly. (2024). introduction to science pedagogy. Limerick: University of Limerick. Lectures 1-12.

Department of education. specification for junior cert science. [Online]. science curriculum. Available at: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.curriculumonline.ie/getmedia/f668d80 [Accessed 5 December 2024].