The examination paper comprised six questions totalling fifty marks. The paper was, according to the teacher, supposed to be the easiest in the subject as it only examined the basic concepts in all the topics covered in the syllabus. Students were asked to be as brief as possible, therefore, no questions demanding students to describe and explain had been asked. Going through the question paper, though, revealed three questions with some parts that needed the students to either describe or explain certain processes and phenomena. This paper was not set according to the prescriptions of the syllabus which asserts that only recall questions had to be set and not application questions. The paper was 75 minutes long whereas, according to the syllabus, it should have been one hour long with a total of 40 marks. In short the structure of the paper was not what the students would have expected.
In question one (a) Vincent displayed poor classroom science semiotic formations when he stated that an insect has a compound pair of eyes instead of a pair of compound eyes; which the teacher marked as correct. In the second part of question one all the three students failed to underline the generic names of the larvae they were identifying and the teacher did not penalise them for that. In question two the teacher showed inconsistency in marking by penalising Sarah for wrong spelling and not penalising Vincent. Sarah wrote calciam instead of calcium and Vincent wrote insisors instead of incisor. In part (c) of question two Sharon and Vincent had difficulty since they had to explain how bacteria enter
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the dentine during tooth decay. Vincent got the part wrong by not explaining the process of tooth decay from the surface of the tooth through the enamel into the dentine. He also used everyday science resources and formations and failed to answer the question which needed him to explain how a tooth decayed. Sharon used the appropriate science resources and mentioned some of the steps involved in tooth decay. The teacher penalised her for leaving out some of the essential steps involved. In her last sentence though, she mixed scientific vocabulary with everyday science resources when she said “The plaque causes the tooth to be rotten and form a hole.” In her explanation Sharon proved to be operating at the proximal end of the continuum of conceptual understanding since she had incomplete and more proximal understanding of dental decay. She deserved about half the marks though. Sarah’s explanation was good and close to the distal end of conceptual locality. She only missed out a few things like mentioning that the bacteria respire on the sugar to result in the acid that tends to dissolve the enamel.
In question three, the students were given a graph to interpret about the rate of reaction plotted against temperature. All the three students were able to observe the general trend of variation of enzyme activity with temperature. Differences were in the science semiotic resources and formations used in explaining the variations. Sharon’s explanation of what happens from 10°C to 40°C was poor since she mentioned that the enzymes were increasing in temperature, which is incorrect. Her understanding at that point could be described as confused and its locality as proximal. Vincent failed in his science semiotic resources and formations. All three students failed to read the exact optimum temperature from the graph indicating poor relational and numerical skills. The second part of the question was about enzyme activity from 40°C to 60°C. The students interpreted the graph well and gave the correct reason. Only Sharon did not give the full explanation for the observed rate of reaction. She left out a key term “denature” yet the teacher awarded her full marks.
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Question four needed the students to know the characteristics of living organisms together with their definitions. In the question they were given a list of six characteristics from which to choose and fill-in four missing terms in a passage about a truck. Vincent and Sarah scored full marks in the question but Vincent wrote the wrong spelling of excretion which he gave as “excreation”. This is a common mistake among students and it becomes worse when a student has to copy it from the question paper and rewrite it. Sharon only got two correct. In question five students were examined on the human digestive system, a topic the students had done several times earlier in their academic lives. It was poorly answered by all three students considering that out of nine marks Vincent scored three, Sarah five and Sharon one mark. Their answers revealed that they never prepared for a question on this topic. They were all operating around the proximal locality of conceptual understanding, though Sarah proved to be a bit better. Their main problem seemed to be content mastery. Their descriptions of the roles of the liver in digestion and assimilation were incomplete and difficult to follow. Sharon even held a misconception about the functions of hydrochloric acid in the stomach as she said it is for neutralising the digested food in the stomach instead of providing an acidic pH for the proper functioning of proteases, as well as killing germs reaching the stomach with the food from the mouth.
Question six examined the students on the cross-sectional structure of a dicotyledonous leaf. This question too was poorly done by Sharon and Vincent. Only Sarah did it well with 70% while Sharon and Vincent scored 40% each. This was a recall question and needed one-word answers. One would have expected all the students to do extremely well in this question as they did a practical in addition to a normal lesson where they identified the parts and gave their functions. During the practical lesson the teacher also brought many teaching aids for the students to use, including charts, microscope slides and models. Therefore, one would expect the students to operate at the distal locality of the continuum of conceptual understanding. The total scores for the students in this paper were: Sharon 42%, Vincent 54% and Sarah 72%.
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Writing is part of classroom talk, and in most cases is what is assessed in the tests and examinations. The rather low performance of the students in this kind of classroom talk and its dominance in our assessment systems should be worrying to all educators and policymakers alike. Should not classroom discourse be more embracing and its assessment more comprehensive?