Table of Contents
Introduction
Integrated science processes are complex to children in lower grades, these should be developed to grades 5-7 pupils. They involve other processes of science in order to generate knowledge. The following are examples of integral science processes: hypothesising, experimenting, operational definition, controlling variable and collecting and interpreting data
EXPERIMENTING
Experiments when used in Science, are always associated with practical activity. It is activity undertaken to provide support for one theory, to test a hypothesis and to determine the evidence that may be required to enable alternative interpretations to verify or reject a hypothesis. Effective experiments rely on a wide range of knowledge, understanding and skills.
Experimenting is an essential part of the scientist’s way of operating. Pupils think of practical workWork is The transfer of energy from one physical system to a... More as less academically demanding and less like real work” while “some teachers spend more time on it than others. In some cases, engaging in practical workWork is The transfer of energy from one physical system to a... More is forced only because it has been demanded by the examination body.
Setting up an experiment requires explicit definition of variables which are for the focus of investigation and the variables which are controlled. The variables may be discrete (integer values), continuous (any value), categorical (specifies characteristics), or derived (obtained by calculation from more than one value). The variables may be defined as dependent (effect/ outcome), independent (experimenter chooses to change systematically, the causative factor), control (controlled to make the experiment results valid) or interacting (arise due to the effects of two or more independent variables). The teacher needs to identify these variables and the appropriate instruments to measure them.
Practical workWork is The transfer of energy from one physical system to a... More motivates the pupils to do science and keep them interested. It helps the pupils acquire skills and helps promote logical thinking. Further, it helps the students understand, provides opportunity for them to develop communication skills, provides them the opportunity to workWork is The transfer of energy from one physical system to a... More together and learn something from the experience.
In experimenting, at some point, the learners will be introduced to learning basic practical skills and how to use simple measuring instruments. They are also inducted to illustrating laws or principles and proving a theory. At another point, the pupils will be introduced to learning about controlling variables in an investigative workWork is The transfer of energy from one physical system to a... More. In this, the teacher is to plan (feasibility, practicalities and safety implications) the experiment, evaluate it and suggest improvements, question their own understanding of scientific phenomena, and search out more information.
Most experiments seek causes and effects and relationships of phenomena. In experimenting, the required equipment and apparatus need to be set in place. The researcher needs to know the type of measurements required (precisionAccuracy is The number of significant figures given in a num... More), the quantity or readings, and how the records are to be made. The observations are all recorded to lire detail as the experiment proceeds.
The experimenter looks for ways of improving data collection. Many experiments can be carried out by children. For young children a problem can be posed for them to investigate by asking questions such as, ‘what would happen if….?’ ‘What is the effect of…?’ These may be of the trial and error kind or they may be well designed investigations.
When carrying experiments, you will be required to use the scientific methods.
The steps of the Scientific Method are:
• Observation/Research
• Analysis
• Hypothesis
• Experimentation
• Conclusion
CONTROLLING AND MANIPULATING VARIABLES
A variable is a quantity, which can take different values during an investigation or experiment. The variables can be discrete, categorical, derived or continuous. There are dependent and independent variables. The control variables are identified and not manipulated during experiments or investigations. The experimenter ought to establish how the control process is to be done.
According to Brook, Driver & Johnson (1989), when an experiment is set up, it requires “explicit definition of the variable or variables which form the focus of investigation and of other variables which need to be controlled” (p.74). The mental models brought to the experiment; experience and the background of the experimenter significantly influence the design as they have a vague idea of the conceptual framework of the experiment. The vague conceptual framework guides the selection of the variables.
According to UNESCO (1985), “The ability to identify and control the variables in an experiment comes with experience, and should be treated at progressive levels of complexity as the child matures” (p.31). The child comes to understand the implications of the process later in their development. By the time they find out about a control variable, they have found more information from other sources. Occasionally, they recognise the vast number of possible control variables.
Science instructions need to provide opportunities for the children to relate actual experiences with scientific practices by developing their mental models towards the scientific way. This is done through exploring with them the range and limits of certain models and theories in the course of investigations. They have to be helped to step out of their conceptual framework and to explore other alternative models. The teacher helps the learner to identify the variable to vary and why they consider only one variable at a time.
Example 1
In conducting experiments, we search for cause and effect and their relationships. Consider this situation: Two farmers have twenty hens each. One farmer gets an average of twelve eggs a day but the other one gets an average of six only. There are several factors that could have resulted into this. One factor could be that the second farmer was not feeding the hens on the right kind of feed and another one could be wrong amounts of feed.
These factors are called variables. A variable is a quantity which can take different values when carrying out an investigation or experiment. Key variables that define the investigation are two: the independent and dependent variables. The independent variableIndependent variable is a variable whose values are independ... is the causative factor or effect for which the experiment is intended to explore while the dependent variableDependent variable is a variable in a logical or mathematica... is the outcome which is measurable.
For example, in the experiment to show growth of plants, the amount of water would be the independent variableIndependent variable is a variable whose values are independ... because amounts of water supplied to the plant can be varied while the size of the plant is the dependent variableDependent variable is a variable in a logical or mathematica... because its size is dependent on the amount of water supplied. Control variables are the ones that are controlled during the experiment in order to make results valid.
When the effects of two or more independent variables on the dependent variableDependent variable is a variable in a logical or mathematica... are not easily separated, they are ‘called ‘interactive variables’, for example, the effect of moisture and air on irons causes rust.
A good investigative activity devised by the teacher for his/her class should help pupils identify dependent and independent variables and how to control variables. They should also be able to pose questions on what they want to experiment and suggest ways of testing their ideas.
HYPOTHESISING
A hypothesis is a statement put forward to attempt to explain some phenomenon. In simple terms it means a reasonable guess to explain a particular event or observation. In science, a hypothesis is made when there is evidence available that can be investigated using scientific principles.
Often there could be more than one possible explanation to show that a hypothesis needs to be tested to prove it to be true. Pupils develop the skill of hypothesising if they are able to suggest explanations, which are consistent with the evidence as well as with scientific concepts and theories. Furthermore, if they are able to recognise that there can be more than one explanation for an event and be able to use previous knowledge.
Example 1
Suppose you want to demonstrate a perfect score on an experiment in science. You begin by thinking several ways to accomplish this. You should base possibilities on past observations. If you put each possibility into sentence form, using the words if and then you form a hypothesis.
a. If the science experiment is easy, then I will get a perfect score.
b. If am intelligent, then I will get a perfect score.
c. If I prepare adequately, then I will get a perfect score.
INTERPRETING DATA
The words interpret means “to explain the meaning of something.” Interpreting involves finding a pattern, trend or relationship inherent in a set or collection of data. This data can be presented by: a table, a histogram, or a pie chart.
Young children can present information on a histogram after for example, collecting data on the number of girls and boys in their class. The skill is mostly used by older children who have to present data after an experiment and the interpretation requires a higher cognitive level.
OPERATIONAL DEFINITION
Operational definition is a procedure whereby a concept is defined solely in terms of the operations used to produce and measure it. An operational definition, when applied to data collection, is a clear, concise detailed definition of a measure (measured or derived variable). Since a single word may be used in different contexts taking a different meaning in each situation, definitions provide economy of communication. With the operational definition, the definitions are written in terms of how an object works or how it can be used; that is, what is its job or purpose.
Examples
1. Some operational definitions explain how an object can be used.
a. A ruler is a tool that measures the size of an object.
b. A filter paper is a materialMaterial or Matter is anything which has mass and occupies s... used to separate a mixture of soluble and insoluble substances.
2. Other operational definitions may explain how an object works.
a. A ruler contains a series of marks that can be used as a standard when measuring.
A filter paper contains small openings to allow only soluble substances pass through it and trap insoluble mailer as residue
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