Age Range: Secondary

Air Masses: Case Studies

Post date 8 March 2021

Pick one of the synoptic charts below. Can you work out where the wind over the UK is coming from? Try to ignore any fronts, and don’t think about how things might have changed in the past or be about to change in the future.

Now answer the following questions:

What is the wind direction over the UK?_______________

What is the air mass affecting the UK?_________________

Describe the weather, in terms of wind speed, direction, temperature, cloud and precipitation.

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Would you expect any difference in the weather between day and night? __________________________________________________________________________________________________

Would you expect any difference in the weather between the sea/ the windward coast and inland regions? ____________________________________________________________________________________________________________________________________________________________

February 2015

February 2018

May 2020

Octber 2011

October 2017

Air Masses: a Human Board Game

Post date 8 March 2021

Go outside, and chalk the outline of the world’s continents on a suitable surface

Add board game style places to the map, as shown below:

Assign 4 students to be one each of tropical maritime, tropical continental, polar maritime and polar continental air. Ask them to go and stand on their starting position (bold circles above).

They take it in turns to move one position closer to the UK.

Print each of these statements and distribute them amongst your students. Ask them to give one to the appropriate air mass when they think it is appropriate (you can’t have 2 identical statements join an air mass at the same time):

To start with, I am cold

To start with, I am warm

I have travelled South, moving over a warmer part of the Earth’s surface

I have picked up heat

I have cooled down

I have travelled North, moving over a colder part of the Earth’s surface

I have picked up moisture

I have deposited moisture

Convective cloud can form

Layer cloud can form

It is raining in heavy showers

It is drizzling

There may be a summer thunderstorm

At the end, have a look at the statements the air masses have ended up with, and discuss whether it looks right.

The statements provided are the correct number, but you could always throw a few extra in for more debate!

Rubber Ducks: an Unexpected Journey

Post date 8 March 2021

1. Visit https://www.youtube.com/watch?v=_uuMpVf2R8E

2. On 10th January 1992 some 28,800 plastic bath-tub toys splashed into the sea at 44.7°N, 178.1°E. The first ducks arrived on beaches near Sitka in Alaska in September the same year, and then again in 1994, 1998, 2001, and 2003. The bath toys are still washing ashore today.

3. What does this tell us about the oceans?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

4. Complete this table using the rubber ducks on the map, to show where each rubber duck has travelled to and which rubber duck made landfall first.

Date of landfall	Location of landfall	Journey of rubber duck (oceans travelled through, countries passed by)

Extension: Using a map of the world’s ocean currents, identify which currents the ducks travelled on to reach their final destinations.

5. What do the journeys of the rubber ducks tell you about ocean currents?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

6. Why do you think the toys have been able to survive in the oceans since 1992?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

7. Visit https://theoceancleanup.com/great-pacific-garbage-patch/ and watch the video and answer the following questions.

8. What is the Great Pacific Garbage Patch?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

9. How much plastic floats in the Great Pacific Garbage Patch?________________________________________________________________________________________________________________________________________________________________

10. What are the effects on marine life and humans?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

11. Do you think some of the Rubber Ducks might still be in the Great Pacific Garbage Patch? Why?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Passage of a Depression – Animation

Post date 1 March 2021

Worksheet to accompany the animation.

Transition Resources for Year 6/ Post SATS

Post date 9 February 2021

Transition Resources for Year 6/Post SATS

These resources are designed to be used in one session with year 6 (10/ 11 year old) students. Although they will support numeracy, literacy and various other aspects of the curriculum, they are designed to prepare students for secondary school rather than support the year 6 curriculum.

There are 6 suggested activities. Although they are designed to be run sequentially, you may choose to use only some of the activities, or to supplement them with your own ideas.
It should be possible to use these activities with any class size.

Many people, including Ellie Highwood, Cristina Charlton-Perez, Helen Johnson and Laila Gohar, have contributed to these resources.

Guidance Notes – START HERE

Activity 1 – the Difference between Weather and Climate

Powerpoint: Weather-or-Climate

Word Doc: Weather-or-Climate

Activity 2 – Climate Change Graphs

Powerpoint: Climate Change Picture

Excel: Lollipop

Activity 3 – Climate Change Lucky Dip

No resources required

Activity 4 – Weather Risk Game

Powerpoint: Weather Risk Game

Word Document: Money

Activity 5 – Flooding/ Floating Gardens

Powerpoint: Floating Garden Challenge

Activity 6 – Greenhouse Bulldog

No resources required

Carbon Footprint – Worksheet

Post date 4 February 2021

What is a Carbon Footprint?

We will look at a series of calculations that represent the carbon cycle and how CO₂ production is related to energy. You will start to see the energy implications of various fuels and technologies and their CO₂ footprint.

The associated information sheet will provide the data you need to answer the questions below.

How much CO₂ is emitted by the following activities? (calculate them in kg of CO₂)

Driving 100 miles?

(Using 13 litres of petrol or 10 litres diesel)

Using your LED TV for 5 hours a day during a week?

(A 50” LED TV uses 100 watts, to convert to kWh, multiply kW by number of hours)

Boiling water in the electric kettle for a family for a week?

(A kettle uses 1200 W and it takes 3 minutes to boil water and this is done 10 times a day – or does your household drink more hot drinks?)

Heating the water with natural gas for a week of daily 5 minute showers?

(Heating 30 litre of water to 40°C uses 1.1 kWh in the form of gas, where emissions from natural gas are 0.2 kg CO₂/ kWh burned)

Charging mobile phones for the family for a week. With an average of two full charges a day.

(Typical phone charges at 0.015 kWh and takes 2 hours to charge fully)

Play station for 20 hours a week

(A Playstation 4 Pro uses 139 W)

2. How to quantify CO₂ emissions in terms of volume and mass?

How many cubic metres of CO₂ would 5000 kg CO₂ occupy?

A factory states that it releases 10 tons C per year (as greenhouse gas emissions). How many m³ of CO₂e is this?

If UK car emissions released 3 GtC in a year and all the CO₂ remained in the atmosphere, by how much would the CO₂ concentration increase?

Go to see last year´s UK Carbon emissions published by the government (Provisional GHG emissions). In 2019 it was 351.5 Mt CO₂ Considering the UK population is 63 million and the world population is 8.3 billion, are our carbon emissions representative of global average emissions? ((World emissions in 2017 were 36 Bt)

What is today´s CO₂ concentration at Mauna Loa (https://www.esrl.noaa.gov/gmd/ccgg/trends/)? How much has it increased since 1950? How much has it increased since the same month in 2018?

Why has CO₂ not decreased in 2020 if CO₂ emissions have dropped? Is there still last years and the decade before´s emissions in the air or are we still emitting more despite the drop in transport and industry in 2020?

3. Steps towards reaching carbon neutrality

Do you think the UK is on its way to becoming a low carbon economy? Why do you think some countries like Estonia are way behind the UK and countries like Sweden are way ahead?

The UK has a goal of reaching Carbon neutrality by 2050- do you think we are on our way to reaching that?

What percentage of our man-made CO₂ emissions are absorbed by the oceans?

If a fully grown tree absorbs 22 kg of CO₂ per year and an acre of forests 2.5 tons of Carbon, if we wanted to neutralize our country-wide annual emissions of 351.5Mt* CO₂, how many more trees or acres of forest would we need?**

*The latest government statistics on UK annual CO2 emissions (for 2019) was 351.5 Mt CO2 equivalent

**UK forests absorbed 21 million tonnes CO₂ in total in 2020, so they are working away continuously at helping to neutralise our emissions!

Carbon Footprint – Teacher’s Notes

Post date 4 February 2021

Carbon, fossils fuels and CO₂

Carbon is one of the building blocks of life. Humans, animals and plants are made up of organic compounds. We burn wood and fossil fuels to produce energy and power transport, inadvertently releasing the greenhouse gas, CO₂ into the atmosphere. Students will become more aware of the facts and figures that link the carbon cycle with CO₂ emissions and the jargon that is used in the news and in global climate politics.

Chemistry curriculum links: AQA GCSE

3.2.1 Use of amount of substance in relation to masses of pure substances (Moles)

7.1 Carbon compounds as fuels and feedstock

9.2 Carbon dioxide and methane as greenhouse gases

9.2.4 The carbon footprint and its reduction

Chemistry in the activity

Calculating the energy from combustion of different fuels is related to the number of Carbon atoms these hydrocarbons contain. The amount of CO₂ produced upon combustion is our way of measuring the Carbon footprint of energy sources. Electricity is generated from various forms of energy in each country´s electricity mix and the more renewables and the fewer inefficient coal power plants there are, the less CO₂ is released per kWh electricity used. The UK is trying to go below 100 g of CO₂ released per kWh by 2030 and is likely to achieve this before that date.

In the associated worksheet the students will carry out calculations based on a range of information they will find in the corresponding information sheet. They will become familiar with conversions between tons of Carbon and tons of CO₂, the volume of CO₂ and other factors they may hear in the news or that relate to their personal, a country´s or organisation´s carbon emissions.

They will go to websites that provide current global CO₂ levels and a breakdown of the UK´s electricity supply, with the corresponding kg of CO₂ this will emit per unit electricity used. Questions 1&2 use numeracy skills to evaluate and compare different forms of energy and different technologies.

Question 3 is best used as a classroom discussion and covers carbon neutrality, achieving the UK´s Carbon neutrality goals and calculate how many trees they would have to plant to neutralise this year´s CO₂ emissions.

1. Which fuels or activities produce more CO₂?

QUESTIONS

Which of these activities produces more CO₂ emissions? (calculate them in kg of CO₂)

Driving 100 miles?

(Using 13 litres of petrol or 10 litres of diesel)

Petrol = 2.3 x 13, Diesel = 2.7 x 10 = 29.9 kg CO₂ for petrol and 27 kg for diesel

Using your LED TV for 5 hours a day during a week?

(A 50” LED TV uses 100 watts, to convert to kWh, multiply kW by number of hours)

5 x 7 hours at 100 watts = 3.5 kWh = 3.5 kg CO₂

Boiling water in the electric kettle for a family for a week?

(A kettle uses 1200 W and it takes 3 minutes to boil water and this is done 10 times a day – or does your family drink more tea?)

1200 x 10 x 3 x 7 = 210 minutes (3.5 hours) or 4.2 kWh x 0.283 = 1.19 kg CO₂

Heating the water with natural gas for a week of daily 5 minute showers?

(Heating 30 litre of water to 40°C uses 1.1 kWh in the form of gas, where emissions from natural gas are 0.2 kg CO₂/ kWh burned)

Heating the water for a week uses 7.7 kWh so 0.2 x 7.7 is 1.54 kg CO₂

Mobile phone usage for the family in a week. Assume the family does an average of two full charges a day.

(Typical phone charges at 0.015 kWh and takes 2 hours to charge fully)

4 x 7 x 0.005 = 0.014 kWh x 0.283 = 0.396 kg CO₂

Play station for 20 hours a week

(A Playstation 4 Pro uses 139 W)

139 x 20 = 2.4 kWh = 7.87 kg CO₂

2. How to quantify CO₂ emissions in terms of volume and mass?

QUESTIONS

How many cubic metres of CO₂ would 5000 kg CO₂ occupy? 2500 m³
A factory states that it releases 10 tons C per year (for its greenhouse gas emissions). How many m³ of CO₂e is this? 10,000 kg x 44/12 = 36,667 kg CO₂, so ½ x this is 18,333 m³
If UK car emissions released 3 GtC in a year and all the CO₂ remained in the atmosphere, by how much would the CO₂ concentration increase?

0.47 x 3 = 1.41 ppmv

Go to see last year´s UK Carbon emissions published by the government (Provisional GHG emissions). In 2019 it was 351.5 Mt CO₂ Considering the UK population is 63 million and world population is 8.3 billion, are our carbon emissions representative of global average emissions? ((World emissions in 2017 were 36 Bt)

63m/8.3b =0.81 % of population and CO₂ emissions are 351.5Mt/36000Mt = 0.98 %, so the population of the UK creates more CO₂than their population dictates, we produce 0.98/0.81 =1.21 times more CO₂ than the average world population

What is today´s CO₂ concentration at Mauna Loa (https://www.esrl.noaa.gov/gmd/ccgg/trends/)? How much has it increased since 1950? How much has it increased since the same month in 2018?

(figures for 2020) 500 ppm; increase of 100 ppm between 1950 and 2020 (in 70 years), that is a 0.7 ppm average increase; it has increased 4 ppm since 2018 (in 2 years), 2 ppm increase per year. The rate of increase of CO₂ concentration has increased since the 1950s.

Why has CO₂ concentration not decreased in 2020 if CO₂ emissions have dropped?

The lifetime of CO₂ means that it stays around in the atmosphere for many years and you will not see a decrease in the CO₂ from the year that you stop releasing it, it will gradually level off, that is why we need to reach our CO₂ emission peak as early as possible, to see the results a few years later.

3. Steps towards reaching carbon neutrality

QUESTIONS to discuss as a class

Do you think the UK is on its way to becoming a low carbon economy? Why do you think some countries like Estonia are way behind the UK and countries like Sweden are way ahead? (http://www.globalcarbonatlas.org/en/CO2-emissions is a useful information source)

Estonia still burns a lot of coal, hence its high CO₂ emissions. Sweden has 80 % of its electricity from nuclear and renewables

The UK has a goal of reaching Carbon neutrality by 2050- do you think we are on our way to reaching that?
What percentage of our anthropogenic (human) CO₂ emissions are absorbed by the oceans?

31 %

If a fully grown tree absorbs 22 kg of CO₂ per year and an acre of forest, 2.5 tons of Carbon, if we wanted to neutralize our country-wide annual emissions of 351.5Mt* CO₂, how many more trees or acres of forest would we need?**

351500/2.5 = 140600 acres. There are 60 million acres in the UK, so actually, only adding 0.234 % of the land as forests would do this!

*The latest government statistics on UK annual CO2 emissions (for 2019) was 351.5 Mt CO2 equivalent

**UK forests absorbed 21 million tonnes CO₂ in total in 2020, so they are working away continuously at helping to neutralise our emissions!

Carbon Footprint – Information Sheet

Post date 4 February 2021

1. Which fuels or activities produce more energy or CO₂?

What are fossil fuels made up of? Hydrocarbons with varying amounts of Carbon:

Coal contains large complex hydrocarbon molecules (with C:H:O ratios of ~85C:5H:10O)
Diesel is made up of alkanes containing 12 or more carbon atoms. (e.g. C₁₃H₂₈)
Petrol contains alkanes and cyclo-alkanes with between 5 and 12 Carbon atoms (with an average composition of C₈H₁₂ (octane))
The mass of one mole of pure Carbon is 12 g and the mass of one mole of CO₂ is 12 + (2×16) = 44 g (to convert from CO₂e to C multiply by 12/44)

What are the combustion reactions and how much energy and CO₂ do they produce?

1 kg of petrol burned yields about 47 MJ of energy (1litre, 34.2MJ)
1 kg of diesel burned yields about 46 MJ of energy (1litre, 38.6MJ) (diesel is denser than petrol and has more energy per litre)
1 kg of coal burned yields about 30 MJ of energy
1 kg of wood burned yields about 19 MJ of energy
1 kg of coal (containing 0.78 kg Carbon) will produce 2.4 kg of CO₂
1 litre of petrol (containing 0.63 kg of carbon) will produce 2.3 kg of CO₂
1 litre of diesel (containing 0.72 kg of carbon) will produce 2.7 kg of CO₂

The most up-to-date information on the make-up of the UK electricity grid (which is a mix of sources) can be found at RENSmart and the value in February 2021 was that 1 kWh produces 0.23314 kg CO₂. (kWh are calculated by multiplying kW by the number of hours). If you live in another country you could compare its CO₂ emissions per kWh electricity factor. Here is a good comparison site for many countries but with older data.

2. How to quantify CO₂ emissions in terms of volume and mass?

Volume and mass of CO₂

You will often hear about kg of CO₂ emitted, relating to the energy usage of different forms of transport, of a household, of a company, of a particular industry (like the cement industry) or of a country or a person.

From what we know about the combustion processes, their efficiency and our energy needs, we can use emission factors to calculate carbon footprints. We also know that a mole of any gas occupies 22.4 dm³ at ambient temperature. So we can express the emissions as a volume of CO₂. If we know how much of a gas is emitted and what the original concentration of that gas was in the atmosphere, we can see whether the emissions will change the concentration.

1 kg pure CO₂ occupies a volume of half a cubic metre (500 dm³ (or litres))
CO₂ emissions are often stated in GtC (10⁹ tonnes (or Gigatonnes) of Carbon)
Concentrations of CO₂ in the atmosphere are expressed in parts per million by volume (ppmv). 1 ppmv takes up 0.0001% of the volume of the atmosphere. Check out the Mauna Loa CO₂ measurement station in Hawai for today´s level.
A release of CO₂containing 1 GtC would increase the atmospheric CO₂ concentration by 0.47 ppmv if all the CO₂ remained in the atmosphere, BUT carbon sinks nearly balance out the sources
There was a CO₂ increase of 2.5 ± 0.1 ppmv between 2017 and 2018
The lifetime of CO₂ is 5 to 100 years

Don’t forget:

The mass of one mole of pure Carbon is 12 g and the mass of one mole of CO₂ is 12 + (2×16) = 44 g (to convert from CO₂eq to C multiply by 12/44)

Effects of the Covid-19 on the economy and thus CO2 emissions

Between 2019 and 2020 global CO₂ emissions decreased due to the COVID-19 Pandemic (in the region of 4 Gt CO₂ and the CO₂ emissions fell by 7 % in 2020, the largest ever decrease since the Second World War!)
A Carbon brief article suggests that in 2020 we reduced the annual increase in CO₂ concentrations by 0.32ppmv, putting it at 2.48ppm.
Note the difference between emissions of CO₂ and actual concentrations. The CO₂ already in the atmosphere from previous year´s emissions (it lasts up to one hundred years).

3. Steps towards carbon neutrality

This Figure shows the latest (calculated every 3 months) fuel source mix for the UK electricity supply. Go to: OFGEM. Note the elimination of coal and the increase in wind and solar energy.

The UK electricity supply now has well over 20 % from renewables. The UK is trying to get to below 100 g CO₂/ kWh by 2030 and we might achieve 5 % renewables by 2025. In late 2019 the electricity from British windfarms, solar panels and renewable biomass plants surpassed fossil fuels for the first time since the UK’s first power plant fired up in 1882.

We saw in section 1 that at RENSmart you can get the latest value for how many kg CO₂ are produced per kWh of electricity. Let´s compare other countries from the table at the bottom of this website. Sweden currently has an emission of 0.013 kg CO₂/ kWh (21 times lower CO₂ emissions per kWh!). In Sweden 80 % of electricity comes from nuclear and renewables (with 66 % from renewables). By the way, renewables do have an embedded energy (of up to 50 g CO₂/ kWh).

And look what these natural Carbon Sinks can do:

Between 1994 and 2007, the oceans absorbed 34 Gt CO₂ (31 % of what humans put into the atmosphere during that time)
One acre of new forest can sequester about 2.5 tons of carbon annually. Young trees absorb CO₂ at a rate of 6 kg per tree each year and after 10 years they absorb 22 kg of CO₂ per year. At that rate, they release enough oxygen back into the atmosphere to support two human beings.

References

Electricity generation mix by quarter and fuel source (GB), Ofgem website

Latest “UK CO₂(eq) emissions due to electricity generation”, RENSmart website

Plunge in carbon emissions from lockdowns will not slow climate change, National Geographic, May 2020

Temporary reduction in daily global CO₂ emissions during the COVID-19 forced confinement, Nature Climate Change, May 2020

Analysis: Half of UK’s electricity to be renewable by 2025, Carbon Brief, April 2019

Analysis: What impact will the coronavirus pandemic have on atmospheric CO_2,? Carbon brief, May 2020

Renewable electricity overtakes fossil fuels in UK for first time, The Guardian, October 2019

Oceans absorb almost 1/3 of global CO2 emissions, but at what cost?, World Economic Forum, March 2019

Global Carbon Atlas

Particulate Matter, ice, albedo and melting – Worksheet

Post date 4 February 2021

Have a look at these two glaciers, one has fresh snow over the glacier and the other is a dry glacier in summer with accumulated deposits of dust and Black Carbon from air pollution. Which one do you think is more vulnerable to melting? Does a bright white surface reflect more or less light than a darkened surface?

Fresh clean snow on the Silvretta glacier, Switzerland (Zoë Fleming)

Dirty ice on the Fox Glacier, New Zealand (Sylvia Knight)

Particulate Matter is solid particles that are so small that they float in the atmosphere. They are formed from incomplete combustion of wood and fossil fuels. When they are smaller than 2.5 microns (2.5 x 10^-9 m, an eight the width of a human hair), this PM_2.5 can enter into our lungs and be carried into the blood system and cause damage to the brain and the cardiovascular system.

When Particulate Matter (or Black Carbon, which is more or less soot or pure Carbon) settles on glaciers and snow it darkens the colour of the snow and hence changes the how much of the Sun’s light the snow reflects. In this experiment we will check to see whether dirty or clean ice melts faster.

Materials

Chemicals	Apparatus
3 ice cubes per group	3 bowls for placing ice cubes
Soot or Activated Carbon or burn a splint and gather the blackened combusted material	Spotlight
Soil or sand (as light coloured as possible)	Measuring scale
	Spoon or forceps to move the ice cube between the bowl and the measuring scale

Method

Take 3 ice cubes out of the freezer and place one in each bowl.
Scatter soot over the ice cube in one bowl, covering it completely. Scatter the next ice cube with the soil. The last bowl will contain the control ice cube.
Weigh each ice cube (using a spoon or forceps to place it on the scale).
Shine the light bulb over the 3 bowls, trying to equally light/heat them all.
After 5 minutes, remove each ice cube one at a time to weigh them.
After 10 minutes, remove each ice cube one at a time to weigh them.
If you have time to wait for the first ice cube to completely melt, note the time and note down how much was left of the other ice cubes (weigh them).

Results and Questions

Which ice cubes melted faster?
Does covering them with brown or black melt them faster?
Thinking about a sunny day on snow, how do your eyes react to the sunlight? Does it seem like there is more light around or less than on a sunny day walking on bare soil? What about a sunny day on a boat? Do you think there is more or less light reflected back to your eyes than on land? The proportion of the Sun’s light which is reflected by a surface is called its albedo – a high albedo means a large proportion of the light is reflected and, therefore, only a small proportion is absorbed.
What about the difference between wearing white or black clothes on a sunny day- which one absorbs the sun rays and makes you feel warmer? Is that a small or large albedo?

Application for the world’s glaciers:

Glaciers around the world are more exposed to particulate matter now than they ever were before the industrial revolution. Covering them with a dark material changes the albedo. The darker the surface, the more of the Sun’s light is absorbed by the glacier, warming it and melting it.

Particulates are tiny solid or liquid particles that are present in the atmosphere. They are sometimes termed aerosols as they float in the air. Black carbon (soot) is a particulate released from incomplete combustion. It absorbs the Sun’s light, which actually helps to cool the Earth. However, when it lands on ice, the absorption of radiation speeds up the ice´s melting as the light is absorbed by the dark colour and heats up the ice.

Social and political perspectives:

Knowing that air pollution that reaches glaciers is increasing their melting faster than what would happen from air temperature changes alone, what do you think we can do in terms of laws or behaviour change?

How can we reduce soot and Black Carbon reaching glaciers? Emission control of cars? Banning domestic wood-burning? Have you heard of smokeless coal that can be used in stoves in smoke-free zones? And pellet stoves, are there fewer emissions from these?

Note: You could carry out your own experiment if you are lucky enough to get snow. Prepare two neat snow blocks or two snow-balls of similar size and cover one with gravel or sand and leave the other clean. Watch which one melts first.

Particulate Matter, ice, albedo and melting – Teacher’s Notes

Post date 4 February 2021

In this experiment the students will look at the effect of Particulate matter or other substances that have landed on ice and test how this can speed up the melting of ice by affecting its albedo. Particulate Matter and aerosols are made up of a variety of pollutants, some of them enhancing and some counteracting the greenhouse effect when they are in the atmosphere. But once they land on snow or ice, they will promote the melting of these surfaces.

Chemistry Curriculum Links AQA GCSE

9.2.3. Properties and effects of atmospheric pollutants

Particulate Matter is a pollutant that absorbs at many different wavelengths, some act as greenhouse gases and others actually reflect more light than they absorb, leading to a reduction in the temperature of the atmosphere. When they (or Black Carbon in particular) deposit on snow and glaciers, they change the albedo (the reflectivity) of the snow surface. This controls the heat balance at the surface of snow and ice surfaces as the darker colour of the ice will lead to it melting faster.

Particulate Matter is solid particles that are so small that they float in the atmosphere and can be measured as a concentration in the atmosphere. They are formed from incomplete combustion of wood and fossil fuels. PM smaller than 2.5 microns (2.5 x 10^-9 m), PM_2.5 , is much smaller than the width of a human hair and can enter into our lungs and be carried into the blood system and cause damage to the brain and the cardiovascular system.

Uncertainties to do with the quantities of the different particles in the atmosphere (and the fact that particles enhance cloud formation) are part of the biggest current uncertainty in climate models.

Class Practical

This experiment can be carried out in pairs or larger groups and takes about 20 minutes.

Follow the notes in the student worksheet, allowing more time to discuss what particulate matter is, what is albedo and how sunlight is absorbed differently by different coloured substances.

Discussion Questions

Which ice cubes melted faster? Was it what they expected?
Did all groups get similar results? Can we compare the melting rates as a % of original mass and see if they are similar between groups? What is the error in the melting rate of the 3 types of ice cubes?
Does covering them with brown or black melt them faster?
What are the possible errors in the experiment?

Application to the World’s Glaciers:

Glaciers around the world are more exposed to particulate matter now than they ever were before the industrial revolution and the increase in industry and cars over the last century. Covering snow and ice with a dark layer changes the albedo and they absorb more heat and melt quicker than the pure ice.

Particulates are tiny solid or liquid particles that are present in the atmosphere. They are sometimes termed aerosols when they float in the air. Examples are dust, spores and pollen, salt from sea spray, volcanic ash and smoke. Black carbon (elemental carbon (soot) or organic carbon) from incomplete combustion in the atmosphere can actually absorb incoming solar radiation and cool the Earth. However, when these particles land on ice, the absorption of radiation will enhance the ice´s melting.

References

Iain Stewart BBC black ice experiment

UN Environment programme, 2019: Glaciers are melting and air pollution is the cause

See bar chart of radiative forcing of various gases or particulates in Fig 14.4 Ramaswami et al., 2019

Transition Resources for Year 6/Post SATS