What are the effects of acid rain? | 11-14 years

Students work in a small team to explore the effects of acid rain. There is an experimental investigation followed up with a short field work task to identify and record evidence of the effects of acid rain in their local environment. These tasks provide a focus for students’ thinking, discussion and action that will develop investigation and group work skills. The tasks will take a number of weeks to complete.

Learning objectives

Students will:

• Recognise the effects of acid rain on metals and carbonate rocks.
• Be able to make careful observations over a period of time.

Sequence of activities

Introduction

1. Show a photograph, using a data projector if available, of a building affected by acid rain. (If a piece of stone from such a structure is available, passing this round the class will be even more striking.)
2. Share the learning objectives with the students.
3. Explain that they are going to be working in groups of four over an extended period to find out about the effects of acid rain in the laboratory and in the local environment.

Experimental investigation: stage 1

1. Arrange students in groups of four.
2. Give each student a copy of the ‘Activity sheet’.
3. Outline the first task which is to plan an investigation in the laboratory to find out how acid rain affects certain rocks and metal over a period of three weeks.
4. Display a list of the materials available to students (also on the ‘Activity sheet’).

Experimental investigation: stage 2

Support students while they:

1. Produce their own individual plan.
2. Share their ideas with the other three members of the group.
3. Agree a joint plan.

Questions are given on the ‘Activity sheet’ to help these discussions.

For each group:

1. Check their ideas.
2. Help them develop their ideas further if necessary.

Ask questions that focus thinking on ideas such as fair testing, change over time, recording observations effectively, sharing observations within the group, an appropriate risk assessment.

Experimental investigation: stage 3

Arrange for laboratory time for the three week period for the tests and for storage of equipment between observations. Support and monitor the tests over the three week period.

Field work: stage 1

Circulate and support students while they:

1. Reconvene in their groups.
2. Brainstorm ideas for places to seek evidence of the effect of acid rain in the environment.
3. Develop their ideas further, if necessary.

Ask questions such as ’Which local buildings are very old?’, ’Do we have any statues in our neighbourhood?’ and ‘Where might metal be exposed to rain?’.

Check at the end of this session that all groups have some ideas that are likely to result in them finding useful evidence.

Field work: stage 2

Circulate and support students while they:

1. Reconvene in their groups in a later session.
2. Share their ideas about places with each other.
3. Share ideas between groups if some have not completed this part of their work effectively.

Discuss the availability of digital cameras from home and/or school to help record evidence.

Set clear deadlines for collecting evidence.

Presentation preparation

Support groups as they:

1. Collate and analyse the data from their laboratory tests and the evidence collected from the local environment.
2. Plan what they are going to include and who is going to make what contribution to the project.
3. Produce a poster or an ICT presentation.

Presentation and plenary

1. Arrange a ‘grand finale’ for this extended piece of work in which groups showcase their posters or give their ICT presentations.
2. Ask each group to write down one feature which they liked about other posters or presentations and one way in which they think they could be made even better.
3. In a plenary, use the groups’ comments to draw up a class view of what makes a good poster or presentation.

Commentary

Graphic examples of acid rain effects will illuminate the learning objectives.

The evaluation of ideas, through working in a team, stimulates students to think about their ideas more thoroughly. Collaboration skills are also developed, not only by the group work but by students specifically reviewing their input.

Comments on the final presentations lead students to recognise the standards they are aiming for.

Practical notes

Equipment

For the experimental investigation:

• Solution of 0.005 mol dm^-3 sulfuric acid (IRRITANT) labelled ‘Acid Rain’
• Small pieces of:
  • chalk
  • marble
  • slate
  • lime-cemented sandstone, eg Cotswold type
  • iron
  • copper
  • zinc
  • lead
• Small containers for the test materials which can be kept over a three week period
• Plastic pipettes for adding drops of acid rain to rocks and metals
• Hand lenses
• Labels or pen to identify test materials
• Access to a digital camera if available

For the posters:

• A3 paper
• Scissors
• Adhesive
• Felt tip pens

To produce digital presentations:

• Access to laptops or a computer suite

Health, safety and technical notes

• Read our standard health and safety guidance.
• It is the responsibility of the teacher to carry out an appropriate risk assessment.

 Principal hazard

• Sulfuric acid

Answers

Plan for the investigation

1. Label eight Petri dishes one to eight. Pour a small amount of ‘acid rain’ into each. Mark the level of the acid rain with a felt tip pen.
2. Write a key to identify the following different substances: chalk, marble, slate, lime‑cemented sandstone, iron, copper, zinc, lead.
3. Place a sample of each substance in a separate dish so that part of it is in the acid rain and part is not.
4. Make a note of what happens as soon as a material is added to the acid rain.
5. Store the dishes for a week.
6. At the end of the week, examine each substance and make a note of any changes before returning it to the acid rain. Add water to the acid rain to bring it up to the original level.
7. At the end of the second week examine each substance and make a note of any changes before returning it to the acid rain. Add water to the acid rain to bring it up to the original level.
8. At the end of the third week examine each substance and make a note of any changes.

Suggested table

Headings should include: ‘Substance’, ‘Behaviour when first added to acid rain’, ’Changes at end of first week’, ‘Changes at end of second week’, and ‘Changes at end of third week’.