Teaching overview

Learning points

  • Traffic congestion is one of the biggest causes of air pollution in cities around the world.
  • Cities are introducing driverless and electric buses that can carry several people at once and don't produce any exhaust pipe emissions.
  • Some cities have also started charging car drivers to enter the city centre, or banning them completely at certain times of day.

Curriculum keywords

  • Pollution
  • STEM
  • Renewable energy
  • Transportation

Multimedia toolbox

Traffic video loop

Play the audio loop after the film and ask students to think about how often they hear these sounds. How would these noises affect students if they heard them all the time?

The introduction of harmful substances to a natural environment.


Show the visual after the film to reinforce terminology.

Driverless bus visual

Show this visual after the film and ask students what they think the advantages and disadvantages might be of having driverless buses.

Noise pollution audio loop

Play the audio loop after the film and ask students to think about how often they hear these sounds. How would these noises affect students if they heard them all the time?

Spark a discussion

  • Why might public transport be better for the environment than cars?
  • What are some sources of air pollution other than exhaust pipe emissions? Are they all man-made?
  • How could you reduce your impact on the quality of air in your neighbourhood?
  • What effects can air pollution have on humans’ health?
  • Why are people less likely to notice air pollution than some other kinds of pollution?
  • Lots of traffic produces noise pollution, which can be bad for your health. How would you try to reduce the amount of noise pollution in a city?
  • Fuel used by vehicles sometimes leaks. When it does, what effects does it have on the environment?
  • Oil spills are caused by malfunctioning boats on water and vehicles and factories on land. What kind of impact does oil and fuel have on water, soil, and land? Can it affect plants, animals and humans?
  • What types of technology can you think of that are helping to reduce human impact on our planet?


How acidic is the rain around you?

INVESTIGATE the acidity of local rainfall.

Open detailed instructions

Other activity ideas

  • RESEARCH ways air quality can be improved other than those mentioned in the video.
  • CLASSIFY reasons for car usage as essential vs. optional.
  • PLAN a local campaign encouraging people to leave their cars at home and take public transport.
  • CONDUCT a traffic survey on roads near the school at different times of day to see how many cars are occupied by just one person.
Print this sheet

How acidic is the rain around you?

Duration: 45 minutes


  • Medium-sized plastic container (capacity of around 1 litre)
  • Blue litmus paper strips
  • Pipette (1 per student pair)
  • Test tube (1 per student pair)
  • Test tube rack (1 per student pair)

Key Learning:

Students will understand that acid rain is polluted rain that damages the environment. They will also understand how to use litmus paper to test the acidity of their local rainfall, and that acidity is measured on the PH scale.

Activity preparation: Plan to hold the activity after some rainfall. Set up a container outside to collect rainwater. Ideally, you should collect enough for each pair to test a test tube’s worth of water.

Activity instructions:

  1. Begin a class discussion about acids. You can use the following prompt questions:
    • What is an acid? Can you think of anything acidic?
    • How do we measure acidity?
  2. Explain that an acid is a type of chemical that can dissolve and wear away substances. Tell students that we measure acidity using a scale known as the PH scale. Explain that any substance that scores less than 7 on the PH scale is acidic. The lower the number, the more acidic the substance.
  3. Tell students that some foods are acidic. Explain that you can usually tell which foods these are because they taste sour.
  4. Ask:
    • Can anybody name any sour food?
  5. If nobody mentions citrus fruit, tell students that these types of fruit – e.g. oranges, lemons, limes, grapefruit – contain lots of citric acid. Explain to students that this is why they should brush their teeth regularly – if they drink a lot of orange juice, for example, the acid can dissolve their teeth over time!
  6. Ask:
    • Has anybody heard of acid rain? Do you know what it is?
    • Do you think that acid rain has an effect on the environment?
    • What do you think might cause acid rain?
  7. Explain to students that acid rain is caused when pollution makes its way into our atmosphere. Chemical reactions cause the rain to become more acidic. Over time, this acid rain has negative effects on the environment: it can damage plants and affect marine life. Acid rain can also wear away structures made of steel, such as bridges, and buildings made of marble or limestone.
  8. Tell students that they are now going to test the acidity of the local rain. Explain that you have collected rainwater from the last few days for them.
  9. Ask students to come up one pair at a time to collect their rainwater sample. Explain that they should use a pipette to collect the water from the container and place it into their test tube.
  10. Tell each pair to place their test tube of rainwater carefully into their test tube rack.
  11. Ask students to take their strip of blue litmus paper and dip it into their rainwater sample. Explain that the paper will turn red if the water is acidic. The redder it becomes, the more acidic the rain.
  12. Ask students to share their results.

Background information

  • There are currently more than 800 million cars in use worldwide, which together burn 1 trillion litres of fuel a year. The vast majority of these cars rely on fossil fuels, a non-renewable energy resource which is slowly running out.
  • Sourcing fossil fuels can be destructive for the surrounding environment – fracking can cause chemical pollutants to leak into the ground and oil spills can destroy wildlife for miles around – but burning fossil fuels also has the negative effect of releasing carbon dioxide, nitrogen and methane into the atmosphere. These substances contribute to smog, acid rain, and the greenhouse effect, which traps the heat from the Sun in Earth’s atmosphere and causes rising temperatures globally.
  • Hybrid vehicles or vehicles powered by electricity are on the rise – they don’t release harmful gases into the atmosphere, and if they use energy from renewable sources, such as wind, hydro or solar, they don’t rely on fossil fuels either.
  • Many efforts are made to reduce air pollution caused by exhaust pipe emissions. Los Angeles introduced rules calling for cleaner fuels, while Paris banned cars in some historic areas and encouraged the use of bicycles. In Freiburg, Germany, people who live without cars are offered cheaper housing, free access to public transport, and good access to bicycle routes. Offering access to reliable and efficient public transport is an effective way of reducing the numbers of cars on roads.
  • Cities choked with cars aren’t just bad for the environment, they’re bad for our health too. Air pollution can cause lung diseases, asthma, bronchitis and cancer, heart disease, and type 2 diabetes. Exhaust pipe emissions can also affect local wildlife habitats: acid rain caused by air pollution can change the quality of soil and water where animals live, and can limit the amount of nutrients available to plants.
  • A busy city can also produce a large amount of noise pollution, which is simply noise that our ears cannot easily tune out. This can include noise from road traffic, trains and planes. Noise pollution can make it difficult to sleep, which in turn can cause a number of health problems, such as high blood pressure or heart disease. In an attempt to limit noise pollution produced by cars, the UK laws forbid cars from using their horns in certain urban areas at night.


The introduction of harmful substances to a natural environment.
Fossil fuel
Fuels that were formed millions of years ago from buried plant and animal remains. The three types of fossil fuels are natural gas, coal, and oil.
Greenhouse gas
One of several gases in Earth's atmosphere that trap heat close to the planet's surface.

Explore our resources

Complete your lesson with teaching resources on noise pollution from Tigtag.

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Discover free online CPD for primary science from Reach Out CPD.

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