mechanical phenomena: uniform rectilinear · pdf fileuniform rectilinear motion subject:...

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

Mechanical Phenomena: Uniform Rectilinear Motion

Subject: PhysicsGrade level: Secondary EducationAnticipated time: two 60-minute lessons and two 80-minute lessonsDeveloper: I. Tomozeiu

Abstract

The module engages pupils in understanding the notion of mechanical motion, the terminology, concepts and methods specific to the study of the uniform rectilinear motion; it develops their capacities of exploring the reality and experimenting by using instruments and procedures. The motion of certain bodies floating on the water surface of the school vicinity river and the speed of different bodies can be measured. We suggest using both traditional instruments (chronometer, measuring tape) and motion detector GO MOTION. By going outside in the nature pupils will develop a critical attitude regarding the science effects upon the technology and social development, will stimulate their interest in environment protection.

Institution: University of PiteştiCountry: Romania

University of Piteşti, Romania


PEDAGOGICAL FRAMEWORK

Learning Physics in gymnasium is entirely influenced by the way in which one introduces the

concepts. In this sense it is recommendable that the organizing of the didactic approach

corresponding to each learning unit, should take into consideration three sequences which can be

synthesized as:

• familiarization;

• structuring;

• application.

The activities assumed by the teacher in a learning demarche:

(1) Sequence - familiarization:

The teacher’s role: bringing up-to-date and problematization

- creates learning situations which will make pupils remember the notions, the operations and

the behaviours necessary to the understanding of the concept which is to be taught;

- establishes the pupils’ level of knowledge of some notions related to the concept which is to

be taught;

- proposes tests of initial evaluation;

- facilitates the pupil’s searching demarche;

- motivates pupils to accomplish their tasks;

- requires situations taken from the real life, stimulating for pupils, defines the terms related to

the new concept when the pupils carried on multiple experiments or enough trials.

(2) Sequence – structuring:

The teacher’s role: systematization and conceptualization

- essentializes the observations done by pupils regarding the studied topic;

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- helps the pupils express what they observed, formulate conclusions on the basis of the

observations and of the findings made;

- introduces the new terms, corresponding to the studied topic;

- helps the pupils idealize through models and generalize to other objects, the observations

made during the exploration activity;

- helps the pupils describe and define the new notions and concepts.

(3) Sequence – application:

Teacher’s role: study and transfer

- proposes and orientates applicative working tasks;

- proposes further activities to go deeply in the studied topic;

- offers the pupils opportunities to develop independently ideas, to exercise independently the

proposed applications;

- proposes new and varied contexts, for the applying of the models;

- extends learning outside the classroom.

BACKGROUND KNOWLEDGE

The pupils participating to the project’s activities study the mechanical motion (the uniform

rectilinear motion) starting by the 6th grade. Because these do not have the age of 12 years, we

believe it is necessary the teaching of these notions to be achieved in nature, within a relaxing

framework where they can notice, study and understand the phenomena much easier.

We define the notions:

- Body position – the place where a body is placed at a certain moment of time;

- Mobile – body in motion;

- Reference system – the set composed by a body and a watch, related to which we report the

position of the studied body;

- State of motion – the state in which the studied changes its position in time related to the

reference system;

- State of rest - the state in which the studied body does not change its position in time related

to the reference system;

- Trajectory – the way travelled by the mobile in its motion related to a reference system;

- Run distance – the distance between two positions of the mobile;

- Motion duration – the period of time in which the mobile was in motion ;

- Average speed – the ratio between the mobile’s displacement and the duration of its motion;

- Uniform rectilinear motion – the motion in which the trajectory of the mobile is a straight

line and its speed is constant in time;

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- Uniform motion law – in the uniform motion the displacement is directly proportional with

motion’s duration;

- Motion graphic – the graphic representation of the mobile’s displacement as a time function;

NECESSARY MATERIALS

Brochures;

Tests;

Chronometer;

Measuring tape;

Millimetre paper;

Different bodies from nature;

Ael system

PowerPoint Presentation

Motion Detector - GO MOTION (cod 2320.10 of Altay catalogue)

Interface - DATALogger ( cod 2320.30 of Altay catalogue)

Graphic laptop

CONTEXT

The School “Valea Ursului”, the Bascov rivulet 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 kilometres. The village is

placed on the right side of the Argeş River having

the coordinates latitude N 44050’ and longitude E

24052’. The landscape consists of field and hills with an altitude of 200 – 300 meters, hills on

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which there are forests of oaks, maples and beech wood. The Bascov rivulet passes through the

village on a distance of approximately 15 kilometres and then pours out in the Argeş River. It

presents a continuous flowing regime, a well defined river bed, with shores of 2.5 – 3 m height

and average width of 30 – 40 m.

The School “Valea ursului” with grades from 1st to 8th is on the right side of the rivulet in the

vicinity of a nice oak forest. For the study of the bodies’ motion we decided to determine the

speed of the water on Bascov rivulet on a water portion with smooth flow and the determination

of the speed of a pupil running for the Youth Competition organized by the municipality.

The activities are carried on in the classroom and in the middle of the nature.

In the classroom, the pupils acquire notions necessary to the study of the phenomena related to

the uniform rectilinear motion.

The activities carried on in nature aim at connecting to the direct reality, one accentuating the

assimilation and the practical acquiring of the theoretical knowledge, acquired during the classes.

The lessons have as main objective the adaptation of the contents to the surrounding

environment, to the immediate reality, i.e. learning in the middle of the nature. In the middle of

the nature we relax, we accumulate energy, the relations teacher-pupil and pupil-pupil become

friendlier and the educative-instructive process more pleasant.

INSTRUCTIVE ACTIVITIES

Lesson 1

Duration: 60 minutes

Objective

Teaching the necessary notions for the study of the rectilinear and uniform bodies’ motion.

Description of activity

In the Physics lab the pupils watch an educative film which renders obvious the notions

necessary to the uniform and rectilinear motion study.

During the presentation the teacher intervenes, challenging discussions among the pupils upon

the observed phenomena so that the pupils understand correctly the notions: position, mobile,

reference system, state of motion, state of rest, trajectory, distance, duration.

The teacher defines the average speed, the uniform rectilinear motion and the motion law.

Together with the pupils solves the following problems:

Lecture: “Ionel is in the 6th grade. Every morning, when the watch in his room shows the time

7 h and 20 min, having the schoolbag in his hand, he starts from home towards the school. The

school is at 240 m far from his house. At 7 h 25 min, Ionel is in the Physics laboratory.”

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Please specify: The reference system, Ionel’s position related to the selected reference system,

duration of the motion, the displacement and the average speed.

Which are the elements needed to be specified in order to localize the position of a vehicle on a

linear road?

A mobile passes near the landmark numbered “10” at 9 h 10 min and near the landmark

numbered “20” at 9 h 20 min.

Please determine the displacement, the duration of the motion and the mobile’s average speed.

A mobile displaces based on the motion law: d = 2t +1. Draw the graph of the motion.

At the end of the activity the pupils resolve the following test paper which verifies the

knowledge accumulated during the activity:

1. Draw the graph of the following motion:

O A B C

t(s) 0 5 6 7 9d(m) 0 20 20 20 30

2. Calculate the mobile’s speed for each segment:

V1 =

V2 =

V3 =

3. Which is the mobile’s total displacement?

∆dtotal =

4. For how long the motion did last?

∆ttotal =

5. Which is the average speed of the mobile during the whole motion?

Vmedie =

Evaluation of activity

From the analysis of the tests solved by the pupils one may observe if these ones understood the

taught notions and if they are able to operate with them in solving problems.

Lesson 2

Determinations of speeds and constructions of graphics


Objectives

- identifying in nature the notions studied during the previous activity.

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- pupils’ getting used to working with different measurement instruments with the view to

carrying on some quantitative determinations.

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


The teacher requires the pupils to form groups of five with the view to achieving measurements.

Each group of pupils will receive a working sheet, a measuring tape and a chronometer.

Working sheet

1. Identify bodies around you.

2. Select a reference point and determine the position of the identified bodies related to it.

3. Mention what misses to the reference point for this to become a reference system.

4. Classify the identified bodies based on their mechanical state.

5. Choose a reference point on the shore of the rivulet. Find floating bodies. Using the

chronometer and the measuring tape fill in the following table:

t (s) 0 1 2 3 4 5 6 7 8 9 10d (m)

The groups of pupils accompanied by the teacher go

towards the river nearby school where they look for areas

with a slow flow with the view to effectuating

measurements necessary. The pupils fill in working sheet

and design the graphic motion.

Out of the graphics they determine the average speed of the

water. They compare the results obtained and after some discussions they find the sources of

errors.

The activity is filmed.


Analysing and discussing the value tables and the graphics built by the groups of pupils.

The teacher asks the groups of pupils to choose a representative who to present the answers of

the tasks rendered within the working paper. Together with pupils forming the other groups, he

draws out conclusions upon the correctness of the given answers and upon the working mode.

Extension

The teacher encourages the pupils to go to the computer science laboratory or to the information

centre of the school to find out answers to the following questions:

- What other instruments can be used for determining the speed?

- Where can the graphic of some bodies’ motion be used?

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The pupils are informed that they will provide the answers to the above questions during the next

class.

Lesson 3

Presentation and use of the motion detector GO MOTION


Objective

- using the detector in the study of the bodies’ motion

- becoming aware of the advantages of the motion sensors use.


Teacher asks the pupils to present the answers found out for the questions of the previous

activity.

The pupils describe the identified measurement instruments, where and how the graph of the

motion can be used.

The teacher presents to the pupils the motion detector GO MOTION and teaches them how to

use it, studying the motion of a pupil in the classroom. One achieves a collection of position and

speed data and using the computer one presents directly the motion graphic proving the utility –

the facility in use and the speed of achieving the graphic with the help of the detector.

The groups of pupils formed during the previous lesson go in the forest near the school where,

using the motion detector record the data necessary to the motion study of a pupil who is training

himself to attend the Youth Running Competition organized in the Pitesti Town. Accompanied

by the teacher, the pupils go to the river and record the data necessary to the study of the river

flow.

When returning into the Physics lab, with the help of the computer, they observe the graphics of

the studied motions and take down the values of the average speeds.

One is aware of the fact that using the motion detector the pupils obtained the necessary data

faster and more precisely. At the end of the activity the teacher requires the teacher to save the

obtained data in a folder.

The activity is video taped.


Analysing and discussing the materials saved by the pupils in the computer.

Observing the way in which the groups of pupils have worked by studying the movie realized

during the previous activities. Together with the pupils, the behaviour of the groups during the

activities will be analysed, conclusion will be drawn concerning the necessity of using the

motion detector and the necessity of protecting the environment will be emphasized.

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Extension

Identify new situations in which one can use the motion detector.

The study of a boat motion on a river:

- motion in the sense of the river’s flow

- motion in the sense opposed to the river’s flow.

- motion on a perpendicular direction during or on the shortest way

Lesson 4

Achieving portfolios


Objective

Giving arguments for the importance of using the Go Motion detector in the bodies’ motion

study.


In the classroom or in the nature, depending on the weather, the teacher requires the pupils to

make a drawing or an essay where they should present where and how they can use the motion

detector in the study of the phenomena occurred in nature. During the presentation of drawings

and essays realized by pupils, the teacher will initiate debates upon these.

The pupils will fill in a portfolio which will contain:

- the notions taught during the 1st activity

- tables of value, the obtained graphics and the conclusions from activities 2 and 3

- the drawings and the achieved essays.

At the end of the activities, pupils will receive the following questionnaire:

• Which of the project’s activities seemed to you the most interesting?

• Do you think that it was easier to obtain the graph of the bodies’ motion by using the motion

detector?

• Would you like to perform other activities in the nature? Why?

Please give arguments for your answers.


Analysis of the portfolios and questionnaires received from pupils.

Extension

Within the methodological commissions of the teacher of sciences in the school, the pupils

present the project’s activities, underlining the necessity of using the motion detector in the study

of bodies’ motion.

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Within the pedagogic round table of the Physics teachers, one presents the motion detector, the

pupils’ portfolios and the possibilities of using it in the study of bodies’ motion in gravitational

field.

BIBLIOGRAPHY:

1. Curricula for the 6th and 7th forms

2. Physics methodological guide

3. Physics evaluation guide

4. Methodics of teaching Physics

5. Physics, the 4th form

6. General Catalogue of Sciences 2007 Altay

7. Science Achievement in Middle School Years, IEA - Boston College Chestnut Hill, 1996

8. School Background with Science Achievement - Main Survey - Boston College Chestnut Hill,

2000

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