Tag: Integrated Science,Science Education,Science Teacher’s guide

The major hazards associated with electricity in the science laboratory that require somesafety measuresare electrical shock and fire.Electrical shockoccurs when the body becomes part of the electric circuit, either when an individual comes in contact with both wires of an electrical circuit, one wire of a live circuit and the ground, or a metallic part that has become live by contact with an electrical conductor.

ELECTRICITYRELATED HAZARDS

The severity and effects of an electrical shock depend on a number of factors, such as the pathway through the body, the amount of current, the length of time of the exposure, and whether the skin is wet or dry. Water is a great conductor of electricity, allowing current to flow more easily in wet conditions and through wet skin. The effect of the shock may range from a slight tingle to severe burns to cardiac arrest.

The table above shows the general relationship between the degree of injury and amount of current. While reading this table, keep in mind that most electrical circuits can provide, under normal conditions, up to 20,000 milliamperes of current flow.

In addition to the electrical shock hazards, sparks from electrical equipment can serve as an ignition source for flammable or explosive vapours or combustible materials.

PREVENTING ELECTRICAL HAZARDS

There are various ways of protecting people from the hazards caused by electricity, including insulation, guarding, grounding, and electrical protective devices. But first, the following care should be taken when dealing with lab work involving electricity.

(i) Inspect wiring of equipment before each use. Replace damaged electrical cables immediately.

(ii) Use safe work practices every time electrical equipment is used.

(iii) Know the location and how to operate shut-off switches and/or circuit breaker panels. Use these devices to shut off equipment in the event of a fire or electrocution.

(iv) Limit the use of extension cords. Use only for temporary operations and then only for short periods of time.

(v) Multi-plug adapters must have circuit breakers or fuses.

(vi) Minimise the potential for water or chemical spills on or near electrical equipment.

Insulation

All electrical cables should have sufficient insulation to prevent direct contact with wires. In a laboratory, it is particularly important to check all cables before each use, since corrosive chemicals or solvents may erode the insulation.

Damaged cables should be repaired or taken out of service immediately, especially in wet environments such as cold rooms and near water baths.

Grounding/earthing

Only equipment with three-prong plugs should be used in the laboratory. The third prong provides a path to ground for internal electrical short circuits, thereby meeting the user from a potential electrical shock.

Circuit Protection Devices

Circuit protection devices are designed to automatically limit or shut off the flow of electricity in the event of a ground-fault, overload or short circuit in the wiring system. Circuit breakers and fuses are two well-known examples of such devices.

Fuse and circuit breaker

Fuses and circuit breakers prevent over-heating of wires and components that might otherwise create fire hazards. They disconnect the circuit when it becomes overloaded. This overload protection is very useful for equipment that is left on for extended periods of time.

SAFE WORK PRACTICES

The following practices may reduce risk of injury or fire when working with electrical equipment:

1. Avoid contact with live electrical circuits.
2. Use guarding around exposed circuits and sources of live electricity.
3. Disconnect the power source before servicing or repairing electrical equipment.
4. When it is necessary to handle equipment that is plugged in, be sure hands are dry and, when possible, wear nonconductive gloves and shoes with insulated soles.
5. If it is safe to do so, work with only one hand, keeping the other hand at your side or in your pocket, away from all conductive material. This precaution reduces the likelihood of accidents that result in current passing through the chest cavity.
6. Minimise the use of electrical equipment in cold rooms or other areas where condensation is likely. If equipment must be used in such areas, mount the equipment on a wall or vertical panel.
7. If water or a chemical is spilled onto equipment, shut off power at the main switch or circuit breaker and unplug the equipment.
8. If an individual comes in contact with a live electrical conductor, do not touch the equipment, cable or person. Disconnect the power source from the circuit breaker or pull out the plug using a leather belt.
9. Repairs of high voltage or high current equipment should be performed only by trained electricians.

In order for you to understand why you have to teach science to the primary school pupils, you need to study the goals forscience educationin this country. Teaching science in primary school is a very delicate issue because children start encountering formal science learning at this level. You need to acquaint yourself to some of the documents that talk about primary science education in Zambia such as Educating our future (policy document on education) and the Zambia Basic Education Syllabus.

THE RATIONALE OF TEACHING SCIENCE IN PRIMARY

Teachingsciencein primary, although it does obviously include content, is equally about establishing attitudes and working practices, which will first catch and then nurture the germinal concepts of learners. It gives the learners clear understanding of basic concepts, enabling them to acquire capacity to grasp more intricate science undertakings. Through this approach, they become more specific, more a meticulous, laterally thinking and persevering. Whole process is an effort to create a more scientifically literate community.

Teachers place a significant imprint in the minds of the learners under their care and their worldview. The views of the science teachers shape theirteaching approachesin class. The teaching approaches in turn influence the learners’ views and perceptions, their attitudes, values and interest in science. Science educators have the task of preparing students for multiple roles and responsibilities in the society including managing naturally occurring scientific problems in a thoughtful and reasonably accurate way.

The bases and frameworks of the goals and objective of science education for science teachers and curriculum designers are as follows:

1. a)Science has an intrinsic value as a body of accumulated knowledge and as a way of finding out about the world.
2. b)Learning science is a means of helping individuals to fulfil their own personal potential.
3. c)Learning science helps the individual to learn to live in a society and both to contribute to it and benefit from it.

RESPONSIBILITIES OF THE SCIENCE TEACHER

The science teacher has the responsibility to develop in the learners, abilities, attitudes, concepts, intellectual skills and manipulative skills of doing science and acting scientifically by applyingscientific knowledge. Pupils need to be aware of how rapidly science progresses and should be able to argue for the positive scientific development, having learnt the basic level of scientific literacy at school. They ought to help the learner acquire scientific competencies and know when and where to use and communicate such scientific knowledge. This involves reflection of the acquisition of knowledge and application of knowledge, understanding, and skills of scientific inquiry and the capacity to test them.

Good teaching requires an awareness of, among other things, the skills that can be developed by working in a scientific way. Further, if we are to bring them (learner) into the present century, they must be made to appreciate the uncertainty of science, and to know that theories are speculations or guesses that must be discarded or modified as soon as they fail to fit observations. Children must know that no one really knows. When we give pupils the insights, then they will have learnt science no matter what content they have covered. This approach to teaching science promotes the use of processes of science.

EFFECTIVE TEACHING OF SCIENCE

Effectiveness of Science Education program will be manifested on how pupils interpret their environment, what is happening in their surrounding and the day-to-day life experiences. The process should help the learner develop the following:

• An understanding and appreciation of his/her relationship to his/her environment and confidence in his ability to effect changes and improvement in the environment.
• An awareness of, interest in and curiosity about natural phenomena of his environment, and a commitment to seek a scientific explanation of these phenomena.
• An understanding of a selection of significant scientific facts and theories, and the ability to apply them in relevant situations.
• His/her critical thinking ability and a reduction in tendency to adopt opinions based on unsupported or unreliable evidence.
• An understanding and appreciation of the methods of science, and the past and possible future contribution of science to mankind.

DEFICIENCIES IN TEACHING SCIENCE

Many science classes show deficiencies in course planning, course content and methodology. There is need to contextualise science education to the situation of the learner thus linking it to the social, cultural and personal issues. This requires use of experiments and experimental data to challenge the positions that are otherwise taken for granted. Balance in practical work should be geared towards problem-solving rather than illustrating previously taught theories. This promotes innovation and creativity.

Science education programs need to start from the context of the learner. There are often significant disparities between the ideas children bring to the lesson and the ideas the teacher assumes that they would bring, the scientific problem the teacher would like the children to investigate and what they consider the problem for investigation, activity proposed by the teacher and those undertaken by the pupils, the children’s conclusion and the conclusion proposed by the teacher.Although there are some impressive exceptions, too much of the time spent learning science by too many pupils consists of the accumulation of facts and principles which have little perceived or indeed actual, relevance to their daily lives as young people or as adults.

The science teachers are expected to encourage pupils, develop learning experiences that allow the pupils to take responsibility, and value pupil’s hypotheses, conclusions and generate discussions from there. You have to appreciate pupils’ ideas, and promote interactive teaching.

CONSTRUCTIVIST APPROACH

Constructivism is a perception of the way learning takes place from the learner’s -standpoint. Learning then is an active process where the learners construct new ideasor concepts based upon their current and past knowledge and experiences. The learners select and transform information, construct hypotheses, and make decisions, they rely on a cognitive structure to do so. Constructivism therefore views individuals as active constructors of understanding from their own worldview.

Instructional processes must create predisposition towards learning, organise instructional programs in a way that they are easily grasped by the learners, create the most effective sequence of the material to be addressed, and effectively pace reinforcement facilities.

Constructivist approach to teaching science demands that:

• The process begins with what learner already knows, understands and can do.
• Learners become constructors of their own knowledge with guidance of the teacher. The teacher does not necessarily provide the right answer or how appropriate solution can be found.
• Learner to learner communication in speech is a necessary ingredient. Universal terms are introduced when it is appropriate to do so.
• The focal point of the whole learning environment is each separate individual learner albeit in-group context.
• Teaching is a process of enabling. It comprises ceaseless assessment of all learners, individually and appropriate action responses.

Sciencecomes from a Latin wordScientiawhich means knowledge or any systematic way of recording knowledge. Scientia is derived fromscire, which means, to know.Philosophy of scienceseeks to understand the nature and justification of scientific knowledge and the meaning of science.

There are several definitions of science given. Some of these are: Science is both a body of knowledge (accumulated by the scientists) and a process of acquiring (the way in which they acquire) knowledge.Science is knowledge; it is dynamic knowledge. It involves knowledge (of facts, theories, laws, models and concepts) and a process (method), which develops this knowledge. This leads to discovering or explaining the state of things the way they are and to be able to predict how they are probably going to be in future. Science is a method of exploring and investigating the world around us (natural and generated), the universe (cosmos) in order to deepen understanding.

Science is a systematic observation and classification of natural phenomena in order to bring them under general principles and laws. Science is a way of thinking and acting. It is affected by cultural, social, economic, technological and political Contexts. It demands respect for evidence and involves imaginative cross-referencing, elimination of irrelevancies, and use of evidence to explain events.

Through a series of systematic observations, classification and experimentation, scientific generalisations, laws and theories are developed.

NATURE OF SCIENTIFIC KNOWLEDGE

Scientific knowledge is always in continuous change (dynamic). The knowledge obtained through observation, classification and experimentation should be viewed as tentative and is subject to further testing and verification to generate new evidence. Though tentative, it does not diminish the value of the knowledge already obtained. It is based on evidence that is public rather than personal (private) and replicable through further experimentation. The following characteristics may apply to all scientific knowledge.

(a)Tentative

Even though scientific knowledge is durable, it is never absolute or certain. When new evidence is found against existing knowledge, as a result of advancement of technology or old evidence is reinterpreted in the light of new advanced theory, existing knowledge can be altered. Further, uncertainty of scientific knowledge is observed because it is inferential, subjective, creative and culturally embedded in nature.

(b)Inferential

Although scientific knowledge is derived from, and/or consistent with observations of natural phenomena, it is also inferential in nature. Observations are descriptive statements about natural phenomena that are ‘directly’ accessible to the senses (or extensions of the senses). For example, if we release an object above ground level, we can observe its tendency to fall and hit the ground. On the other hand, the object tends to fall to the ground due to the gravity, which is not accessible to our senses and “can only be accessed and/or measured through its manifestations of effects. This logical conclusion of the observation is called aninference.

(c)Theory-driven and subjective

Scientist’s’ theoretical knowledge, training, experience, commitments, religious or other beliefs, political convictions, sex and ethnic origin can form a mind-set that affects scientific investigations. Different scientists holding different values engage themselves in different forms of scientific investigations. Also, these values influence what they observe (and do not observe) and how they interpret these observations. In other words, these observations help find answers to some questions, which are derived from within certain theoretical perspectives.

(d)Scientific knowledge involves human inference, imagination, and creativity

Despite having an empirical basis of scientific knowledge, it involves scientist’s imagination and creativity. Further,scientific knowledgeis probabilistic, historic (builds on past data), unique, humanistic (involves creative imagination and product of culture), holistic and empirical.