Specification Coverage

The lesson looks at the composition of the air today, and the idea that natural events and human activities will affect the levels of trace gases in the atmosphere.

Course resources / Key terms
Activity pack / Active Teach / deforestation
noble gases
trace
C1.4a Atmosphere card sort
C1.4b Human effects on the atmosphere
C1.4c The gases in air
C1.4d Data from ice cores
C1.4e Burning fossil fuels / AT Volcanic emission data [worksheet]
AT Student summary table [spreadsheet]

Specification coverage

1.8 Describe the current composition of the atmosphere and interpret data sources showing this information

1.9 Demonstrate an understanding of how small changes in the atmosphere occur through: a) volcanic activity b) human activity, including the burning of fossil fuels, farming and deforestation

HSW 1 The collection and analysis of scientific data

HSW 14 How uncertainties in scientific knowledge and scientific ideas change over time and the role of the scientific community in validating these changes

The tasks in this lesson also provide opportunities to cover HSW 2 and HSW 13

Starter 1: Atmosphere card sort
In Worksheet 1.4a students cut out and sort the cards to match up all the information about the four main gases in air. The cards have the names, formulae and percentages. / Starter 2: Air concept map
Lit
Students could work in pairs to start to create a concept map of their learning during this topic. Provide students with a list of all the important words and terms. They should arrange these around the phrase ‘Earth’s sea and atmosphere’, placing related terms near each other and sketching arrows to show the links. They should be encouraged to explain the links orally using full sentences, perhaps to another pair. They can amend and complete their maps in Plenary 1.
Exploring 1: Human effects on the atmosphere
Lit
Worksheet C1.4b provides cards with information about human activities that change the proportion of some gases in the atmosphere. Each student is given one card and is asked to prepare to explain that idea to other students. They then get into groups with a student who has prepared each theory. Students then share their theories with each other in their groups. Ask students to underline no more than three key points on each card, then each student should write a brief summary of the five ideas.
Working towards A*: Students should be given card 4 to explain.
Working towards E: Students should be given card 3 to explain. / Exploring 2: Volcanic emission data (AT)
The AT has a spreadsheet with data about volcanic gases in different locations. Students should use the data to explain why it casts some potential doubt on the idea that nitrogen was released by volcanoes. Students could also use the data to create a comparative bar chart using a spreadsheet and a series of pie charts. Students could comment on which is the best way to present the data. Note that the origin of nitrogen in the atmosphere is not a specification requirement.
Working towards A*: Students could explain how this data does not rule out the idea that nitrogen was released by volcanoes because there are only three data sets and volcanoes in the past will not necessarily have produced the gases in the same relative quantities as they do today.
Working towards E: Students should use the second page of the spreadsheet, which gives names of gases.
Exploring 3: Burning fossil fuels
Demo/Prac This is a simple experiment to show that the oxygen in air is used up when fuels, such as the wax in a candle, burn, and a demonstration to show that carbon dioxide and water vapour are formed. See Worksheet C1.4e and the Teacher and technician practical sheet C1.4 for full details.
Working towards A*: Ask students to explain chemically how and why carbon dioxide and water vapour are formed when many fuels are burned.
Working towards E: Students may need help to calculate the amount of oxygen used up when the candle burns. / Explaining 1: Student Book spread C1.4 (AT)
The Student Book looks at processes that can change the amount of some trace gases in air. The impact of human activities will link to work in Unit C1.5 on acid rain and incomplete combustion, and in Unit B1.3 on air pollution. Students could draw a summary table naming each gas and describe processes that add it to the air.
Working towards A*: Make sure that students understand that the impact of farming includes the use of fossil fuels in transportation and in manufacturing fertilisers.
Working towards E: The AT contains a grid that students could use for their summary.
Plenary 1: Concept map
AfL
Students could update their concept map to reflect learning from this lesson and ideas formed after speaking to other pairs. Words or phrases could be added along the arrows to explain the links. / Plenary 2: Quiz questions
AfL
Students work in pairs to write four quiz questions about this spread and then use them with at least one other pair.
Homework 1: The gases in air
Worksheet C1.4c is aimed at students needing support and requires interpretation of pie charts and drawing of bar charts.
Working towards E: Students may need some guidance on calculating percentages. / Homework 2: Using ice core data
More able students complete Worksheet C1.4d which looks at the use of ice core data to show how carbon dioxide levels have changed in the atmosphere over hundreds of thousands of years.
Working towards A*: Students answer the Extra challenge question.

By the end of this lesson…

The majority of students may have:

· described that the main gas in air is nitrogen at 78% and that other component gases are 21% oxygen and 0.9% argon, with trace amounts of other gases including carbon dioxide and water vapour

· given some examples of how natural events such as volcanic eruptions, and human activities such as burning fossil fuels, deforestation and farming may affect the amounts of the trace gases in the atmosphere

· HSW 1 explained why a scientific team has collected and analysed data in a certain way

· HSW 14 described how uncertainties in scientific knowledge about recent changes in the Earth’s atmosphere are adjusted over time as more observational evidence becomes available to test ideas, describing how other scientists review reports before they are published (peer review) to question new ideas and validate findings.

In addition, students working towards A* may have:

· HSW14 explained how the scientific community critically evaluates evidence from a wide range of sources to obtain further evidence and validate/check/revise scientific theories.

Students working towards E may have:

· described that the main gas in air is nitrogen

· demonstrated that natural events and human activities may affect the amount of the trace gases in the atmosphere

· HSW 1 stated that scientific research involves asking questions that can be answered by using experiments

· HSW 14 described how scientists publish reports to share new explanations.