Unit 7 Living Things and Air

Topic

Balance of carbon dioxide and oxygen in nature

Curriculum Link

7 Living Things and Air (The effect of the increasing amount of carbon dioxide in the atmosphere on us)

Estimated Lesson Time

80 minutes

Introduction

It is a well-known fact to farmers that the temperature inside a building with a glass ceiling that is transparent to sunlight is higher than the outside.  Plants that need a warmer environment can grow inside such a building, which is called a greenhouse.  Similar effect to produce warmer air in the atmosphere by greenhouse gases is called the natural greenhouse effect.

Some gases can produce such greenhouse effect and they are called greenhouse gases.  Carbon dioxide is one of the greenhouse gases.

The issue of global warming, i.e. an increasing trend of average temperature on Earth, is frequently reported in the news in the past few decades.  Scientists believe that the large amount of carbon dioxide released into the atmosphere by burning fossil fuels in the past few decades upsets the balance of carbon dioxide in nature.  As a result, the greenhouse effect of warming the air in the atmosphere is becoming an imminent threat to us.

This investigation is going to study the effects of greenhouse gases in the atmosphere by measuring the temperature inside two closed environments.  One of the environments is a set of an apparatus that is identical to the air.  Another environment is a set of apparatus prepared to contain mostly carbon dioxide.

Key Question

How significant is the effect of greenhouse gases on the temperature of the air in the atmosphere?

Learning Objectives

In this activity, the students should be able to

  1. recognize that carbon dioxide is a greenhouse gas;
  2. acquire planning and designing skills (SP3) in designing an experiment to measure and compare the temperature of two closed environments;
  3. acquire measuring skills (SP1) and experimenting skills (SP4) in preparing two setups accordingly and measuring the temperatures;
  4. acquire comparing and classifying skills (SP2) by identifying the trend of temperature in two different environments;
  5. acquire interpreting data skills (SP5) in analyzing the data collected.

Teaching Plan

Task (Time) Brief Description Materials Objectives

Engagement
(20 min)
  • Teacher shows some newspaper clips about scientists' concern about greenhouse effect on the atmosphere
  • Students carry out a search on the effect of the increasing amount of carbon dioxide in the atmosphere
  • Teacher engages students to think about how to produce a relatively large amount of carbon dioxide from items in the daily life.  Teacher can prompt students that soft-drink in fact is carbonic acid gas (i.e. carbon dioxide) dissolved in water.
   (1) & (2)

Exploration
(30 min)
  • Students prepare two closed environments, one with air and another with mostly carbon dioxide
  • Students take relevant measurement at regular intervals
  (2) & (3)

Evaluation
(5 min)

Students analyse the set(s) of data to identify and compare the trend of temperatures measured in the two different environments

 (4)

Elaboration & Explanation
(10 min)
  • Students predict the trend of temperatures if more carbon dioxide is used in one of the closed environments
  • Teacher debriefs students the purpose of preparing a closed environment with air by de-carbonated soft-drink
   (5)

Exploration
(15 min)

If time allows, students repeat the experiment

  • with less/more carbon dioxide to be used in one of the closed environments to check the validity of their conclusion
  • with other types/brands of soft-drink
  • in another day of a different temperature
   (3)

Remarks:

  1. The closed environment with mostly carbon dioxide can be prepared by using Coca-Cola® to produce the needed carbon dioxide because experience shows that Coca-Cola® performs the best.
  2. This experiment has to be carried out on a sunny day.
  3. Since carbon dioxide is denser than the air, the thermometer bulb should be placed in the upper half of the bottle in order to measure the temperature of air.

Apparatus and materials required: