the air – a gaseous solution. air pollution - outlab.ie · •air composition – the air...

Grant Agreement number: 226646 -CP- 1- 2005-1-IE-COMENIUS-C21(2005-3264)

The air – a gaseous solution. Air Pollution

Subject: ChemistryGrade level: Secondary EducationAnticipated time: three 90-minute lessonsDeveloper: A. Tomozeiu

Abstract

The activities engage pupils in knowing and understanding the notions of solution, acid rain phenomenon and in knowing the permitted levels of oxygen & carbon dioxid concentrations and the pH permitted value for the rainfall within the European legislation.We think it is beneficial to propose for the Outlab project the study of the air pollution and the measurement of the rainfall pH in the following locations: in the school yard, at the crossroad in the village/city center and in the forest in a place at significant distance of the European motorway. The activities performed in the nature intend to collect materials and data concerning the quality of the air. These activities have always a large resonance among pupils because the direct contact with the nature constitutes for them moments of active relaxation, of knowledge enrichment, of curiosity satisfaction.Using the obtained data we intend to create at pupils a critical attitude regarding the science effects upon the technology development and upon the social development and also to stimulate their interest upon the environment protection.

Institution: University of PiteştiCountry: Romania

University of Piteşti, Romania


PEDAGOGICAL FRAMEWORK

The educative instructive objectives constitute the reference framework in comparison with

which one must reconsider in systematic vision all the educational process elements found in

interaction, including its contents. The efficiency of the education process depends essentially on

the organizing way of the informational contents, on the way the systematization and the

correlation of information are achieved, and especially on the way some basic concepts are

integrated. Of great importance is the rational structure of the contents, ensuring from the very

beginning of the chemistry study the assimilation of some fundamental concepts, principles and

laws which govern the understanding of the chemical phenomena. In the contents of the

chemistry taught in schools, one introduced the use of the experiment, of the modeling, of the

mathematization, fact which trained the pupils on a unitary vision, not only on chemistry but also

on reality in general.

The formative value of methodology becomes also a method of learning chemistry, giving to the

didactic activity a rediscovering character of the scientific truths, new for pupils.

For the development of the thinking and of the pupils’ independent investigating spirit, one must

use methods such as the mathematization of the knowledge assimilation process, the increase of

the practical laboratory works evaluation, the use of the audio-visual means, the use of the

computer.

For the pupils to achieve learning, acquiring new behaviors, it is necessary that in the teaching-

learning process, the activity of the pupil to be marked the best. Learning becomes efficient in

this way, throwing the pupil in the research activity, obliging him to formulate hypothesis, to

verify them, to look solutions for the solving of different problems. In this context, the teacher

becomes the guide of the pupil whom he helps to organize the activity and work correctly.

An important role in the study of the Chemistry in gymnasium is represented by the materials,

the devices and the apparatus with the help of which one achieves the transmission and the

assimilation of information and also the evaluation of the obtained results.

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The apparatus and the devices can be used both in the lab and outside it for the pupils to achieve

measurements outside the lab for the study of the different properties of the chemical substances.

We do not have to forget that Chemistry is a nature science and consequently we must try to

study it as mush as possible outside the classroom.

BACKGROUND KNOWLEDGE

The air we breathe is part of the atmosphere, the mixture of gases which cover the Globe. This

mixture of gases permits life on earth and protects us from the noxious sun rays.

The atmosphere is made up of about 10 different gases, most if it nitrogen (78%), oxygen (21%).

The 1% left is made up of argon, carbon dioxide, helium and neon. All these are neuter gases,

.i.e. they do not enter into reaction with other substances. There are however traces of sulfur

dioxide, ammoniac, carbon monoxide and ozone as well as noxious gases, smoke, salt, dust and

volcanic ash.

The natural equilibrium of the atmospheric gases which has been maintained for billions of years

is threatened now by the humankind activity. These dangers would be: greenhouse effect, global

warming, air pollution, making thinner the ozone layer and the acid rains.

During the last 200 years the global industrialization deregulated the necessary gases for the

atmospheric equilibrium. Burning the coal and the methane gas led to the formation of some

enormous quantities of carbon dioxide and other gases, especially after the en d of the past

century when the automotive was invented. Development of the agriculture determined the

accumulation of some big quantities of methane gas and nitrogen oxides in the atmosphere.

Within these activities one will study notions related to solutions, and thus one will define the

following notions:

• Dissolution – the phenomenon of spreading of a certain substance’s molecules among the

molecules of another substance

• Solution – the homogenous mixture obtained by dissolving

• The solution’s components –dissolvent and dissolved

• Concentration of solution – the quantity of a substance dissolved within 100 grams of

substance

• Classification of solutions – saturated solutions which contain the maximum quantity of

substance till saturation, non-saturated solutions which can dissolve new quantities of

substance till saturation, diluted solutions which comprise reduced quantities of dissolved

substance, concentrated solutions which comprise a high quantity of dissolved substance.

• Air – a gaseous solution – a homogenous mixture of gases

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• Air composition – the air contains: permanent components (nitrogen, oxygen, rare gases),

variable components (carbon dioxid, water vapors), random components (dust, smog)

• Air specific phenomena – ozone layer, acid rains, greenhouse effect, smog

• Air pollution. Acid rains – The acid rain is a precipitation with pH below 5.6. The

pollutants which contribute to the creation of acid rains are: sulphur oxide from

enterprises of ferrous and non-ferrous metals and as a result of burning the coals inside

the thermo-electrical power plants, nitrogen oxides from the fuel and wood burning. The

process of creation of the acid precipitates (sediments) starts when the two pollutants

reach the atmosphere and, by coming into contract with solar light and water vapours, the

form the acid compounds.

NECESSARY MATERIALS

• Test Tube

• Berzelius Glass

• Glass stick

• Chemical substances

• Plastic tub

• AeL system

• Kit to test the water quality

• pH proof stick code 2317 m 10 from Altay catalogue

• USB Interface, code 2320.30

• Software, code 2300.50

• O2 Gaz Sensor

• Co2 Gas Sensor

CONTEXT

The School “Valea Ursului”, the crossroad in the village and the forest near the school.

Heritage site: The Bascov village is part of a pre-city area of the Piteşti town, the residence of

the Argeş County, related to which the centre of our village is placed at only 7 kilometers. The

village is placed in the North of the Piteşti city, on the right side of the Argeş River having the

coordinates latitude N 44050’ and longitude E 24052’. The landscape of Bascov village is formed

by field and hills with an altitude of 200 – 300 meters, hills on which there are forests of oaks,

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maples and beech wood. Being at the crossroad of some roads of high interest for transportation,

the Bascov village is placed within the area through which a great part of the road traffic towards

and from the West of Europe is performed.

The activities take place in the classroom and outside it.

In the Chemistry lab of the school, the pupils acquire the notions necessary to the solutions’

study and will make investigations on solutions’ dilution and concentration. The teacher

proposes the solving of some problems related to the concentration of solutions. One will also

organize in the lab a workshop on themes related to the surrounding environment degradation

due to air pollution.

The activities carried on in nature aim at collecting materials and data regarding the air quality.

These activities have a great impact on pupils because the direct contact with nature constitute

for them moments of active relaxing, knowledge improvement, and curiosity satisfaction.

INSTRUCTIVE ACTIVITIES

Lesson 1: in the school laboratory

Duration: 90 minutes

Teaching notions related to the solutions

Objective

- Acquiring the notion of solution

- Understanding the phenomenon of

dissolving

- Knowing the properties of air and the

factors polluting the air

- Acquiring skill for working with the laboratory apparatus

- Recognizing and describing certain activities leading to natural disequilibria

Description of activities

Having at his disposal chemical substances: water, kitchen salt, the teacher provokes the

dissolution process and asks the pupils to explain the phenomenon. The pupils try to answer the

teacher’s questions. One defines the solution concept and with the help of the pupils one

discovers the factors which influence the dissolution.

The teacher asks the pupils to answer the questions within the following test:

1. The solution represents:

a) a homogenous mixture, b) a heterogeneous mixture, c) a non-homogenous mixture

2. The components of a solution are:

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a) dissolvent and solvent, b) solvent and water, c) dissolvent and the dissolved substance.

3. The obtaining of a solution is based on the physical phenomenon named:

a) melting, b) dissolution, c) mixing

4. In three glasses there are three solutions of salt: 1) diluted, 2) saturated,3) concentrated:

a) the highest percentage concentration it has the solution in the glass 1

b) the highest percentage concentration it has the solution in the glass 2

c) the highest percentage concentration it has the solution in the glass 3

After the teaching of the notions, the pupils assisted by the teacher, using lab utensils will

prepare different solutions, of different concentrations.

The teacher advises the pupils to use the educative lessons from the modernized educational

system in order to discover the air properties.

The teacher presents the tube for the determination of the pH of a solution and asks the pupils to

prepare solutions of different concentration with the substances found at their disposal. By the

help of the pH probe, pupils will determine the acid or basic feature of the solutions.

At the end of the activities the teacher stimulates the pupils to go to the computer science

laboratory or to the school library to find out materials referring to the air pollution and to the

acid rain phenomenon which to present at the beginning of next activity.

Evaluation of activity

The teacher will monitor the pupils’ activity: - the way the pupils follow the teacher’s

explanations and the way they use the lab devices. At the end of the activity the pupils will pass

a test in order to prove that they understood the taught notions.

Analyzing and discussing the tests.

Lesson 2: outside the lab


To know the acid rain phenomenon, to measure the O2 and CO2 concentrations

Objectives

- getting accustomed with the working skills and with the devices in the lab for a

quantitative and qualitative determination

- getting accustomed with the feeling of belonging to a working group

- familiarising the pupils with the notion of air pollution

Description of activity

In the laboratory the teacher asks the pupils to present the materials which they have found out

about the air pollution and the acid rain phenomenon. During the discussions related to the

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presented materials, the teacher guides the pupils to recognize and to describe the human

activities leading to natural disequilibria.

The teacher divides the class in three groups of pupils and distributes to the pupils the apparatus

and the necessary materials.

The groups of pupils will move to the following locations: the school courtyard, the crossroad in

the commune or forest at a distance of 10 kilometers from the road where they will collect in

plastic tubes the water resulted from the atmospheric phenomena (rain, snow, dew, depending on

the season).

The pupils collect water in small vats and by the help of the probe they will measure the pH of

the samples. In the same location the pupils will perform measurements concerning the

concentration of O2 and CO2. They will fill in the following table:

location sample pH Concentration

of CO2

Concentration

of O2


Analyzing the activities carried out, the behavior within the free activities outside the classroom.

Discussing the tables with the obtained data.

Lesson 3: in the lab


Methods of reducing the air pollution

Objective s

- comparing the obtained values after the measurements carried out with admitted values.

- developing the ecological conscious at pupils.

Description of activities

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In the laboratory the pupils present the results obtained during the previous activity, results

written in tables.

The teacher put at the pupils’ disposal the values permitted by the European legislation related to

the pH value of the water resulted from rainfall and the concentrations of O2, CO2.

The pupils compare the result of own tables to those presented by the teacher and draw the

afferent conclusions.

The teacher initiate a debate based on which pupils will become aware of the necessity to protect

the environment.

The teacher asks the pupils to achieve a portfolio which to contain the theoretical notions taught

during the first activity, the materials realised by them at the library and in the computer science

laboratory concerning the air pollution and the acid rains, the tables obtained as a results of the

measurements, the values permitted by the European legislation related to the pH values and to

the O2, CO2 concentrations, and the identification of the factors which have leaded to the

obtaining of the presented results and also to imagine methods for reducing the pollution.


Analyzing and discussing the conclusions formulated by the pupils and the methods found by

these ones regarding the reduction of the air pollution.

Extension

Having a round table with the participation of the members of the Local Council, the parents,

teachers, local media with the view to presenting the obtained results and the awareness of the

need to reduce the gas emission in the surrounding environment.

BIBLIOGRAPHY

1. Chifu T, Murariu A ,, The basis of the environment protection”

2. Niac G ,, Ecologic Chemistry”

3. Chemistry methodological guide

4. Chemistry evaluation guide

5. ,,Air and water” Encyclopedia Rao

6. General Catalogue of Sciences 2007 Altay

7. http://www.youngreporters.

8. http://ro.wikipedia.org/wiki/Aer

ttp://www.sanatatea.com

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http://ro.wikipedia.org/wiki/Aer

http://www.youngreporters/

the air – a gaseous solution. air pollution - outlab.ie · •air composition – the air...

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