9. Evaluation in Science – Methodology of Teaching Science

9

Evaluation in Science

CHAPTER OUTLINE
LEARNING OBJECTIVES

After reading this chapter, you will be able to:

  • Explain the meaning of evaluation in science

  • Write the importance of evaluation in science

  • Differentiate between measurement, assessment and evaluation

  • State the purpose of evaluation in science

  • Identify and use various tools of evaluation in science

  • Prepare a test for evaluation in science

  • Apply diagnostic test on students to identify their weaknesses in science

  • Plan remedial teaching for slow learners on the basis of diagnostic results

INTRODUCTION

Evaluation as a term is understood to be some kind of assessment, which in turn means that some type of judgments will be made. Now a day, it has become a part of every component of educational process. For a layman, evaluation is equivalent to only marks and grades in tests and exams. However, in reality, it is much more than that. Evaluation is a process by which we try to assess to what extent objectives of teaching science have been achieved. It also gives us information on each student's abilities, skills, interests and the likes. Thus, evaluation is not only measuring the learning level of a student, but it is also a tool, which can be used for enhancement of a student's achievement.

MEASUREMENT Versus ASSESSMENT versus EVALUATION

I. Measurement

Measurement is a process, which involves collection and gathering of data. It is concerned with measuring physical properties (length, height and the like), psychological characteristics (creativity, aptitude and the like) or achievement of a student in a test (17/25 in Biology, 22/25 in physics and the like). No interpretation is made in measurement. It is only quantitative in nature.

II. Assessment

Assessment has a wider meaning as compared to measurement. It includes all the measures needed to find the learner's achievement in any educational programme. Assessment helps in analysing whether the objectives of an educational programme have been achieved or not.

Assessment is one step ahead of measurement as it involves the gathering of data and then interpreting it. For example, marks obtained by a child in science tests will enable the teachers to make judgment about his/her IQ and abilities such as knowledge of science, setting up and performing experiments. It will help in giving rank to the child and thus, it is quantitative in nature.

III. Evaluation

Evaluation is much broader and more comprehensive than measurement and assessment (Figure 9.1). It assesses the progress of a child in science content and experimentation as well as other activities like projects, excursions, textbook analysis, and the likes. Thus, evaluation in science makes qualitative assessments of cognitive, affective and psychomotor domains. It also helps the teachers in knowing whether the objectives of teaching science have been achieved or not. If the objectives have been achieved, the extent of achievement can be assessed. According to Mary Thorpe (1980) “Evaluation is the collection, analysis and interpretation of information about any aspect of a programme of education, as part of a recognized process of judging its effectiveness, its efficiency and any other outcomes it may have”.

 

 

Figure 9.1 Concept of Evaluation

PURPOSE OF EVALUATION

Why do we need evaluation? Evaluation reflects on teaching as well as performance. It is of considerable importance for both, teachers and students. Some of the purposes of evaluation can be listed as (Figure 9.2):

 

 

Figure 9.2 Purpose of Evaluation

  1. To get a feedback on students’ progress in science
  2. To identify the strengths and weaknesses of the science students
  3. To facilitate the grading of the student.
  4. To help the teacher in deciding teaching strategies
  5. To give relevant information to parents so that the performance of a student can be improved
  6. To plan for diagnostic and remedial teaching as per the needs of the students
  7. To assess the relevance of educational objectives, curriculum and methods and initiate changes according to the needs of the students.
TECHNIQUES OF EVALUATION

Keeping in mind the nature of learning outcomes in science, a teacher has to make use of many types of tools for evaluation. A good evaluation programme will include tools and techniques for qualitative as well as quantitative assessment. A technique of evaluation is a process of gathering information in which many tools may be used. Oral tests, class tests, assignments, projects, and the likes are the tools to collect information about a student's performance. These tools are the components of an evaluation technique called examination.

Evaluation techniques and its tools are divided on the basis of the objectives and the nature of science as a subject. No single tool can be used to achieve all the objectives. Further, tools of evaluation can be classified into 2 categories (Figure 9.3)

 

 

Figure 9.3 Techniques of Evaluation

  1. Those measuring cognitive outcomes
  2. Those measuring non-cognitive outcomes

I. Tools to Measure Cognitive Outcomes

1. Written test: At the school level, written tests are generally prepared by the teacher himself/herself. These tests may include essay type questions, short answer type question, very short answer type questions or objective type questions. From the written test, a teacher can find out those areas of learning where many students have gone wrong. Then, tests can be prepared on those topics where the mistakes are being committed. This detailed test can find out the specific points of difficulty.

2. Oral test: Oral tests are used to evaluate those aspects of students’ achievement, which cannot be measured by written tests. These tests include oral questions, debate, discussion, and the likes. The drawbacks of a written test can be compensated by oral tests.

3. Practical examination: Practical exams are somewhat different from the theoretical tests/exams. Here, students are evaluated on their cognitive domain as well as affective domain as they are doing the experiments with the involvement of all the sense organs. During the science practical examination, a students’ performance is assessed in the following aspects:

  1. Practical skills while doing an experiment
  2. Answers to oral questions (viva-voce) on the theoretical knowledge of the experiment as well as the construction and working of the apparatus.
  3. Ability to record and analyse data which can be observed in their practical note books

II. Tools to Measure Non-cognitive Outcomes

  1. Observation: A science teacher can collect general information on students’ achievements by observation. This tool can enable the assessment of a child's emotional stability, critical thinking, maturity, and the likes. Observation of how a child attempts the given assignments, how he/she does the practical work, how the practical notebook is presented and many other activities supplement the evaluation of a child. Confidence, creativity, imagination, argumentation, aptitude, habits and other traits of personality can be evaluated through observation.
  2. Interview: Interviews and oral exams are very similar to each other. Generally, the term, oral exam, is used in lower classes, whereas, the term, interview, is used in higher classes. The questions framed for an interview depends on many factors such as the class of students, duration of the interview and the marks allotted for this tool.
  3. Questionnaire: In a questionnaire, questions are written or typed on a paper and given to the students. The students return them back after writing the answers. Attitude, interest, aptitude, scientific temper, and the likes can be evaluated through this tool. Most of the times, a questionnaire is used when there is a lack of time for an oral test or an interview.
  4. Pupil products: In science, there is a large scope for making charts, models and working models. These products may be inspired from the real life situations. They may be of actual size on contrived. By evaluating these products, the knowledge level of students as well as their creativity, imagination and application abilities can be evaluated.
  5. Rating scale: In a rating scale, all the activities related to the task are listed on the left hand side and a scale is given on the right hand side. Each activity is observed and rated according to a student's performance. In this way, evaluation of a student's skills of drawing diagrams, flow charts, figures, tables, handling equipments, conducting experiments, collecting data, interpreting results can be made. (Figure 9.4)

     

     

    Figure 9.4 Rating Scale

     

  6. Anecdotal records: By observing students’ behavior in certain specific incidents/anecdotes, evaluation can be done on some qualities, such as, tolerance, cooperation, commitment, habits, and the likes. A separate record of such incidents is maintained for every child. These records are analysed over a period and then evaluation is done. For example, during science exhibitions or science fair or science competitions, students can be observed on their co-operation level and at the end of the year, evaluation on this quality can be mentioned in the progress report, separately, for each child. Sim ilarly, other qualities can be evaluated. These types of records are called anecdotal records. (Figure 9.5)

     

     

    Figure 9.5 Anecdotal Records

     

  7. Socio-metric technique: This technique is useful for evaluating the social relationships of students. In this, each student's friendship with other class members is observed. In this way, a teacher can find out the students who do not mix with others and those who mix with everyone. Group formation among the students in a class can be observed. This information helps a science teacher in making groups of students for many academic and co-curricular activities like a project work, a visit to some place of scientific interest, tour, and the likes. For example, when arranging for a tour, students can be grouped for various responsibilities like pre-tour arrangements, discipline, photography, collection of brochures, post-tour follow up, and the likes, depending on their capabilities and interests. (Figure 9.6)

     

     

    Figure 9.6 Sociometric Technique

HOW TO CONSTRUCT A TEST?

An evaluation programme for a science course or a unit should be planned as an integral part of a curriculum. This can be decided only after the objectives of teaching have been stated in behavioural terms and the learning experiences have been planned. The most commonly used tools for evaluation of students’ performance in science are tests. The cognitive domain of the students can be easily evaluated with the help of these.

These tests may be either standardized or prepared by the teachers themselves. Both of them are used in science and have their own advantages and disadvantages. Standardized tests are very reliable. They are easy to score and analyse. Teacher made tests are constructed according to the curricular needs. They are comparatively inexpensive and provide direct feedback to the teacher.

The most commonly used teacher made tests are achievement tests, which may include unit test, term test and annual test. Broadly speaking, these three types of tests do not vary much in their test items, but they differ on the number of units covered by them. A Unit test is given after the completion of one unit, a term test may have more than one units and an annual test covers the whole book. Unit tests are made quite often and they are similar to a class test. Therefore, construction of a unit test is being described here. Construction of a test involves the following steps (Figure 9.7) :

 

 

Figure 9.7 Steps in the Construction of a Unit Test

  1. Planning the test
  2. Framing the questions for the test
  3. Administering and scoring the test

I. Planning the Test

While planning a test, following areas are considered (Figure 9. 8)

 

 

Figure 9.8 Planning the Test

  1. Content to be tested: The content will include a unit and its sub-units. Marks are allotted to each sub unit.
  2. Abilities to be tested: Time available for a unit test is about 50 minutes. In this limited time, three or four abilities of students can be tested. Those abilities (knowledge, comprehension, application, skills, analysis, and synthesis) should be listed and related objectives should be stated in behavioural terms. Marks should be allotted for each ability.
  3. Types of test items: Once the objectives are specified in behavioural terms, next step is deciding how many questions of each type are to be given (very short answer, short answer, long answer, objective type). Marks are decided for each type of item. Make changes in the diagram

On the basis of the content and the abilities to be tested and the types of test items, a blue print of the test can be prepared. A blueprint is a table, which depicts the design (Figure 9.9). It indicates :

 

 

Figure 9.9 The Blueprint of the Test

  1. allocation of marks by content areas
  2. allocation of marks by the abilities to be tested
  3. allocation of marks by the type of test item

II. Framing the Questions

The blueprint enables a science teacher to develop questions for a test. Each question should be framed to test a particular objective, a specific ability and related content. In a test, many types of questions can be framed as already given in the blueprint. These have also been illustrated here (Figure 9.10) :

 

 

Figure 9.10 Types of Test Items

 

i. Long answer type questions (LA): LA or essay type question are constructed to assess logical ability, critical thinking and communication skills besides the knowledge aspect of students. To answer such question, the students have to recall, select, organize and present the related knowledge. LA is a valuable mode for assessment but they are time consuming. Also, scoring of these questions is not objective as accuracy in answers is not possible. Therefore, they are included in unit test but their number is less. Some examples of LA are :

  1. Distinguish between converging and diverging lenses with the help of some examples. Also, mention some of its applications.
  2. Differentiate between a fixed dome and a floating dome biogas plant with the help of a neat and labelled diagram.
  3. Describe the structure and working of a human eye with the help of a neat and labelled diagram.

ii. Short answer type questions (SA): SA is an effective means of ensuring integration of testing with teaching as they provide useful feedback. Appropriate questions can assess many aspects of learning such as, abilities, skills and knowledge. They have following distinctive features :

  • They are easy to construct
  • They take less time to answer
  • They are partially objective in scoring
  • They are take less time in checking

Some examples of SA are given below :

  1. Define dispersion.
  2. What are hydrocarbons?
  3. What is a neuron?

iii. Very short answer type questions (VSA): These types of questions generally test only the knowledge aspect as the answer is to be supplied by a student in one sentence, few words or one word only. Time taken to respond to such questions is very less. There is no possibility of doubt or ambiguity in the answer as it will be either right or wrong and therefore, scoring is very objective, quick and easy. Some VSA are stated here :

  1. What is the ratio, which determines the degree to which light bends while passing from one medium to another?
  2. Give the name of the first stage in the formation of coal.
  3. Name the two types of light sensitive cells.

iv. Objective type questions (O): In simple terms, an objective type question is the one, which is free from any subjective bias. These questions are used to test the knowledge and understanding of the students in science. There can only be one right answer to an objective question but it has to be very short and can be a word, symbol, number or a phrase. Scoring in such questions is very objective, quick and convenient.

However, objective type questions are difficult to make, as they require an extensive effort by the teacher. On the part of the students, their writing abilities cannot be developed and the answers can be given by guess work also.

Objective type question can be of various types :

  1. True/False type
  2. Matching type
  3. Multiple choice type
  4. Completion (Fill in the blanks) type
  5. Classification type

a. True/false type: In these types of questions, some sentences are given which might be right or wrong. The student has to assess whether the given statement is right or wrong and then select the response from true or false, right or wrong, yes or no. These questions provide the opportunities for guessing the right answer. They can be scored quickly and objectively. As very less time is required to answer, these questions can be used for testing large amount of content in a short time.

Examples:

  1. Image formed by a concave lens maybe virtual or real.
  2. Unrefined petroleum is also called crude oil.
  3. The coloured diaphragm of iris has a central aperture called pupil.

b. Matching type: Matching type format consists of two columns—A and B or I and II. In the left column (A or I), incomplete questions and in the right column (B or II), some answers are given. The student has to find the correct option and make a pair. To lessen the guesswork, the answer options in column B are more than the questions in column A. In this form, it must be ensured that the questions are of homogenous nature.

Examples:

 

1. A B
At infinity Same size as the object, virtual, bigger, erect.
Beyond 2F At infinity, real, inverted.
At 2F Beyond 2F, real, magnified, inverted.
Between 2F and F At 2F, real, same size, inverted.
At F Between F and 2F, real, smaller, inverted.
Between F and O At F, real, point sized.
2. A B
  CH4 LPG
C4H10 Natural gas
C10H22 A liquid Hydrocarbon
C18H38 A solid Hydrocarbon
3. A B
  Eye Pinna
Ear Conjuctivita
Nose Supporting cell
Tongue Olfactory Mucosa
Neuron Corpuscles
Skin Sheath

c. Multiple choice type: A multiple-choice question has a stem and options. The stem can be either a direct question or an incomplete statement. There are generally 3–4 options, out of which only one is correct and the rest are distracters. The student has to select the right option and write as per the directions.

Examples:

  1. Which of the following does not include refraction of light?
    1. Formation of an image inside a camera
    2. Formation of an image by a spherical mirror
    3. Formation of images by spectacles
    4. Formation of a spectrum by a prism
  2. Which of the following is derived from a fossil fuel?
    1. LPG
    2. Kerosene
    3. Diesel
    4. Biogas
  3. The message travels along a nerve fiber in the form of
    1. Stimulus
    2. Response
    3. Impulse
    4. Reflex

d. Completion type: Completion type questions are also called fill in the blanks. In this, the student is required to add one or two words to complete an incomplete sentence. The words are needed at the end of the statement. Sometimes, completion type can also be used to prepare questions based on incomplete diagrams, equation, formulae, graph, calculations, and the likes. While preparing such questions, the science teacher should not take the sentence directly from the book. In addition, the sentence given should be meaningful and simple with blanks only for the key words.

Examples:

  1. -------------- is another name for a concave lens.
  2. The concept of atomic bomb is based on nuclear ------------.
  3. -------------- is the master gland.

e. Classification type: In the classification type questions, a group of words or things is presented before the students in which only one word or thing is unrelated or odd. The students are required to either encircle or underline that word. These types of questions are very useful to assess whether the students are able to analyse the relationships between various concepts. Their comparison skills can also be tested.

Examples :

  1. Myopia, Hypermetropia, Presbyopia, Microscope.
  2. Coal, Petroleum, Biogas.
  3. Axon, Receptor, Dendron, Cyton, Dendrites.

After the questions are framed, they should be organized into a test in such a manner that the students can understand how the test is to be attempted; where and how they have to record the answers. The following points should be kept in mind while assembling the questions :

  • Questions should be grouped according to their type, objective type questions (O), very short answer questions (VSA), short answer questions (SA) and long answer questions (LA) should be placed one after the other.
  • Each type of questions should be organized from easy to difficult, that is, among short answer questions, the first item should be the easiest and the last item should be the most difficult. Same pattern should be followed for all types of questions.
  • Simple and clear instructions for students should be mentioned before each type of questions.

A sample question paper of General Science for class VI is being given here.

 

General Science
Time: 1 hr Class – VI M.M.: 50
  1. Fill in the blank space with an appropriate term:

    1 × 5 = 5

    1. ____________means to change into different form.
    2. Rotten food causes ______________ pollution.
    3. Books and copies are ___________ items.
    4. A plane is a flat surface, while an inclined plane is a ___________ surface.
    5. Gears are _________ having grooves.
  2. Correct the following statements by changing the underlined words:

    1 × 3 = 3

    1. Earthworms and some protozoan also breathe through air tubes.
    2. Coal is an igneous rock.
    3. An object floats as long as the buoyant force of water is less than the force of the object.
  3. Name the following:

    1 × 3 = 3

    1. Seeds that remain in a non-living state for a long time but can germinate whenever they get suitable conditions.
    2. Rock used as fuel.
    3. A simple machine used to hold objects like bolts, bottle caps, car top, revolving stools, etc.
  4. State whether the following statements are true or false:

    1 × 4 = 4

    1. A plastic tub is a biodegradable item.
    2. Balanced forces are always equal and opposite in nature.
    3. Vehicular waste causes air pollution.
    4. Slate is an igneous rock.
  5. Match the following:

    1 × 5 = 5

     

    A B
    a)Animal escapes by bluffing Sedimentary rock
    b)Migration Opossum
    c)Shale Endangered
    d)Rhinoceros Dispersal by explosion
    e)Peas Frictional force
      Arctic term
      Soil conservation

     

  6. Differentiate between (Give any one difference):

    2 × 5 = 10

    1. Granite and Limestone.
    2. Gravitational force and Buoyant force.
    3. First class lever and second class lever.
    4. Reptiles and Mammals.
    5. Dead and non-living objects.
  7. Answer the following in brief (Any five):

    3 × 5 = 15

    1. Define energy. Name four natural sources of energy.
    2. How does a simple machine differ from a complicated machine? Also, mention various types of simple machines.
    3. Suggest any four ways by which air pollution can be reduced.
    4. What is soil erosion? How can soil be conserved?
    5. What is the difference between extinct and endangered animals? Give examples of both types of animals.
    6. Differentiate between igneous and metamorphic rocks.(give two differences)
    7. Mention any two ways by which animals protect themselves from their enemies.
  8. Draw a neat and labelled diagram of:

    5 × 1 = 5

    1. A second class lever or a movable pulley

III. Administering and Scoring the Test

Question papers can be hand written, typed or printed depending upon the number of students. In all the cases, a copy of the paper should be given to the students and comfortable seating should be ensured for the conduction of the test.

After the allotted time is over and answer sheets have been collected, they should be scored with the help of already prepared answer key. For short answer questions and long answer questions also, model answers can be prepared which can facilitate the scoring.

After scoring, data can be tabulated and analysed to know about the performance of each student as well as the whole class.

TYPES OF EVALUATION

A science teacher plans for his / her class keeping in mind the content to be taught and the group of students. The students in any class may have different level of intelligence, knowledge and experience. They may be at different levels of learning when they came to the class. During the session, the teacher may feel the need to find the progress of the students. Then, at the end of the class, the science teacher is required to report the achievements of the students. Depending on the time and the purpose of the assessment, evaluation is of three types :

  1. Diagnostic evaluation: conducted in the beginning of a session to find out the level of the previous knowledge of the students and to design learning experiences.
  2. Formative evaluation: done during the session to get a feedback on students’ progress and on teachers’ planning.
  3. Summative evaluation: conducted at the end of the term or, year to grade the students, to collect data for the records and to report it to the parents.

For formative and summative evaluation, oral questions, class work, observation, written test, and the like are employed. These tools have already been explained in the previous section. Diagnostic evaluation is explained in the next section.

I. Diagnostic Test

When a science teacher starts a lesson, he/she asks some questions before introducing the lesson. These questions give assessment of the previous knowledge on which the current class can be based. A class of students may be of three categories:

  • Bright students : These are the extraordinary students.
  • Average students : These students may have some learning difficulties.
  • Below average students : These students have some problems for which the teacher tries to find some specific remedies.

Test and exams are, generally, conducted to evaluate the students. When the students pass in these tests or exams, they are given a division. In addition, if the students fail they are given nothing. To find the cause of failure and to improve it, educational measurement is done which can be of two types :

  • Prognosis test : In this, the learning level of a student is measured. It is carried out with the help of an achievement test conducted in the class as unit test, term test, and the likes.
  • Diagnostic test : In this, the causes of weakness are identified. This test is taken to know the strengths and weaknesses of students. In such tests no marks are given for the right answer and in the case of wrong answer, it serves as the basis or the main cause of the failure. This test can be oral or written.

The characteristics of diagnostic test are as follows :

  1. It is a qualitative test.
  2. No scores are given.
  3. Items are arranged according to the learning sequence.
  4. A subject specialist is needed for the scoring.
  5. Only objective type questions are included.
  6. It is an individual test.

II. Remedial Teaching

Based on the results of diagnostic test, some special provisions are made by the teacher, which are known as remedial measures or remedial teaching. It is a process of testing, teaching, reading and re-teaching the students. It is a continuous process and is specific and exact to correct the errors. Remedial teaching has following functions :

  1. It removes the educational mistakes.
  2. It helps the weak students.
  3. It enables overcoming of the learning difficulties.
  4. It raises the standard of teaching.

Quite often, in the class, the results of the unit tests and the term tests indicate that some students are below average in their achievement in science. To upgrade the performance of such students, remedial measures are needed such as, extra classes, personalized instruction, assignments and the likes. The procedure of remedial teaching is as below:

  1. The teacher should identify the poor students or, the weak students on the basis of tests, marks obtained and observation.
  2. The teacher should identify the specific problem and then specific diagnostic test should be given.
  3. The teacher should give remedial instructions (extra classes, assignments, personalized instructions, and the likes) to the student.
  4. The teacher should evaluate whether the learning difficulties have been removed or not.
SUMMARY
  1. Evaluation is a process by which we try to assess to what extent the objectives of teaching science have been achieved.
  2. Measurement, assessment and evaluation are different. Measurement and assessment are quantitative while evaluation is qualitative.
  3. Evaluation is done with specific purposes. For example, to get a feedback on student's progress, to plan the teaching strategies.
  4. Evaluation can be done to measure cognitive and non-cognitive outcomes.
  5. Tools to measure cognitive outcome—written test, oral test, practical exams.
  6. Tools to measure non-cognitive outcome—observation, interview, questionnaire, pupil products, rating scale, anecdotal records, socio-metric techniques.
  7. Steps in test construction :
    • Planning the test
    • Framing the questions for the test
    • Administering and scoring the test
  8. Planning depends on :
    • The contents to be tested
    • The abilities to be tested
    • The types of test items
  9. Questions are of four types—long answer questions, short answer questions, very short answer questions and objective questions.
  10. Objective questions are of five types :
    • True/false type
    • Matching type
    • Multiple choice type
    • Completion (fill in the blanks) type
    • Classification type
  11. After administering and scoring, data can be tabulated and analysed to know about the performance of each student as well as the whole class.
  12. Evaluation is of three types :
    • Diagnostic evaluation: Conducted in the beginning of a session to find out the level of the previous knowledge and to design the learning experiences.
    • Formative evaluation: Done during the session to get a feedback on students’ progress and on teachers’ planning.
    • Summative evaluation: Conducted at the end of the term or, year to grade the students, to collect data for the records and to report it to the parents.
  13. Based on results of the diagnostic test, remedial teaching can be planned for the needy students.
QUESTIONS
  1. What is meant by evaluation? What are its functions? What methods can be adopted to evaluate the science students ?
  2. How is measurement different from evaluation?
  3. Describe the various techniques and tools of evaluation.
  4. How is a blueprint useful in the planning of a test construction?
  5. How will you construct a test to assess the science students ?
  6. Explain the types of questions that can be included in a unit test.
  7. What is the difference between a diagnostic test and a prognostic test?
  8. As a science teacher, how will you plan a remedial teaching for your class?
  9. What is the role of a diagnostic test in the teaching of science?
  10. What is the purpose of the following in the teaching of science?
    • Achievement test
    • Diagnostic test
    • Remedial measures