Practical endorsement: CPAC student pen portraits, Study Guides, Projects, Research of Biology

Download Practical endorsement: CPAC student pen portraits and more Study Guides, Projects, Research Biology in PDF only on Docsity! CPAC Pen portraits A series of pen portraits has been written to clarify what is meant by 'not achieved', 'achieved' and ‘achieved at a level of competence exceeding the CPAC (Common Practical Assessment Criteria) standard. These exemplars have been developed in collaboration between the four Awarding Bodies: AQA, Eduqas, OCR and Pearson. They are intended for guidance and training purposes, and to give an indication of the standard necessary for each CPAC statement. Although these pen portraits show (in the most part) CPAC skills in isolation, many practical exercises are likely to involve CPAC strands being assessed in combination. CPAC 1: Follows written instructions Not achieved Achieved Exceeds standard Context Chemistry (Year 12): Make up a volumetric solution and carry out a simple acid-base titration. Context Chemistry (Year 12): Make up a volumetric solution and carry out a simple acid-base titration. Context Chemistry (Year 12): Make up a volumetric solution and carry out a simple acid-base titration. Observed The practical lesson started with a full teacher demonstration and safety reminder in addition to all students being provided with a detailed set of written method steps. Working in pairs, glassware and other equipment was collected and set up. One student was responsible for the titration, the other for the preparation of the volumetric solution. There were several requests for reassurance from the teacher, particularly in the initial stages (the steps for the correct weighing procedure were very confused) leading to lots of teacher intervention and a spot demonstration of the drop-wise addition of burette solution towards endpoint. Although the method steps were being followed in the correct order, neither of the students were working independently of the teacher and it was difficult to ascertain the degree of input from each individual student throughout the practical as a whole. Students requested apparatus that was not needed to carry out the written method steps, indicating a lack of forward Observed The student was provided with a full set of written method steps for the practical. This was supported by a brief class discussion at the start to highlight the safety requirements. Independently, the student methodically and confidently followed the method steps in the correct order; firstly to make the volumetric solution, then to carry out the titration work. They generated a set of expected titre volumes of sodium hydrogensulfate solution. Prior to the rough titration, the student asked the teacher for clarification about the number of drops of indicator to add (“2-3 drops” advised on the sheet) and decided to go with 3 drops to enable the endpoint to be seen more clearly. The student proceeded to carry out a further three titration runs, sufficient to ensure that two results were concordant. Observed The class was provided with a simple outline of the practical method steps, as all the students had carried out a number of titration practicals in previous lessons and did not need the heavy ‘scaffold’. Safety information was discussed verbally. Prior to starting, students could be seen reading the outline in full before selecting apparatus independently from a range of glassware provided on a trolley. Both elements of the practical work – making up the standard solution and titration work – were carried out efficiently, methodically and independently with little reference to the written practical outline. The students demonstrated a developing degree of fluency with the techniques and apparatus being used. Students designed and completed a table, the student checking for obvious anomalous titres after each attempt and ensuring that a sufficient amount of results had been collected to achieve concordant titres. All method steps were carried out in the However, the student does not manage to follow the instructions in the correct order and does not add Benedict’s solution prior to heating in the water bath for the first test. This has to be pointed out by the teacher. The student then works independently to collect the expected set of results. All procedural points are carried out in the correct order and the student is methodical and confident in their approach to the task. The teacher does not have to have any involvement. Following this, the student works without intervention from the teacher and collects the expected set of results, having followed all of the method points in the correct order. The student engages in a discussion with the teacher about the temperature the water bath needs to be maintained at to see a result with Benedict’s test and it is agreed that the instructions could be modified slightly. Context Physics (Year 12): Determine the electrical resistivity of a material. Observed A student is working as part of a pair. The student asks the teacher for reassurance that the apparatus provided is correct for the experiment. He takes no part in the setting-up of the circuit, leaving this task to his partner. Context Physics (Year 12): Determine the electrical resistivity of a material. Observed A student is working as part of a pair. The student reads the instructions provided for the practical. She is able to use the circuit diagram from the apparatus provided. With her partner, she asks her teacher to check the circuit, which is correct. Context Physics (Year 12): Determine the electrical resistivity of a material. Observed The student is provided with an outline of the experiment, where some steps are given in outline only. He reads through the instructions provided and is able to formulate a correct method for the task. The worksheet tells students to collect a reading every 10 cm along a 1-metre length of wire. The student collects three readings only, and asks his teacher if this is enough data. At the end of the practical session, she has collected sufficient data, together with her partner, as outlined in the method on the worksheet. He finds all the apparatus independently (CPAC 2d). He sets up the circuit, and checks that it is correct before turning on the power pack. He works methodically to collect the data required, ensuring that it is tabulated and checked as he goes along (CPAC 4b). CPAC 2: Applies investigative approaches and methods when using instruments and equipment Not achieved Achieved Exceeds standard Context Biology (Year 12): Investigation into the effect of a named variable on the rate of an enzyme- controlled reaction. Observed In groups of three, students were invited to plan and carry out an investigation to find out the effect of temperature on the rate of trypsin enzyme. One of the students immediately took the lead and started to write things down. One of the others quickly joined in but the third, who was less familiar with enzyme work through recent absence from school, took a backseat. After a while it was clear to the teacher that little progress was being made as the group were unsure both how to measure trypsin action (dependent variable) or what Context Biology (Year 12): Investigation into the effect of a named variable on the rate of an enzyme-controlled reaction. Observed An individual student was invited to investigate the effect of temperature on the rate of trypsin action. Using previous lesson theory and practical notes, they devised a potential set of simple method steps that would enable sufficient data to be generated. The student asked the teacher to consider what they had done before modifying their method for control of temperature, recognising with little prompting that electrostatically controlled water baths would be a better choice than beakers. From that point, the student chose all the necessary apparatus and prepared all the Context Biology (Year 12): Investigation into the effect of a named variable on the rate of an enzyme- controlled reaction. Observed The teacher gave all the students in the class an open choice of which independent variable they might like to investigate when considering how trypsin enzyme reacts. The teacher provided a list of apparatus and chemicals that would be available to them, plus an indication of the lesson time that would be dedicated to the task. The students had been asked to carry out some research for homework to enable them to independently write a set of method steps to investigate their written hypothesis. Students were then given the the group although they demonstrated a somewhat cavalier approach to collecting the information. There was also some confusion over recording information. One student in the group was able to give a rationale for the way in which they completed the investigation but the other two seemed less clear. It was difficult to be certain who contributed what to the investigation. One student clearly took the lead but the group work was poorly managed which lead to some failures in the 'doing' of the activity. While group work may be allowable under certain circumstances, it is important that the contribution of each student is clearly identifiable and that the students can evidence the key aspects of the CPAC2 skills. In this case, the best that can be said is that one student was working towards aspects of the assessment criteria while the other two showed little evidence. length could be measured without significant error. She decided to increase the length of the pendulum of her shortest run in the light of her experience. The student understood what she was doing and could give clear reasoning for the method she proposed. The student recognised the need to take multiple readings for each period of the pendulum and could give reasons for variations in the period for each length. Context Physics (Year 13): Potential divider investigation. Observed Students working in pairs are unable to get their circuit to operate. The teacher leaves them for 15 to 20 minutes to try and overcome their difficulties before stepping in to guide them to assembling a correctly functioning circuit. Context Physics (Year 13): Potential divider investigation. Observed Students working in pairs are unable to get their circuit to operate. The students work though their circuit and after 15 to 20 minutes overcome their difficulties and are able to collect data as required. (Achieves the use of instruments and equipment although not investigative 2a, b) Context Physics (Year 13): Potential divider investigation. Observed Students working in pairs set up their apparatus with no issues, each participating and communicating with each other. They collect data as required and have completed the task set within twenty minutes. The teacher then asks them to determine the best value for the fixed resistor in their circuit to optimise the range of potential difference output. (Achieves the use of equipment and investigative nature 2a, b, c) Context Biology (Year 12): Investigate a factor affecting the initial rate of an enzyme controlled reaction. Context Biology (Year 12): Investigate a factor affecting the initial rate of an enzyme controlled reaction. Context Biology (Year 12): Investigate a factor affecting the initial rate of an enzyme controlled reaction. Observed Although the student is following a clear outline of the experiment, it is evident that he does not know which variables should be controlled, so ends up varying the temperature, but failing to have a constant amount of enzyme in each experiment. The experimental steps are not carried out in a logical order, and the data collected is to a variety of significant figures. Observed The method followed by the student tells them to vary the concentration of the substrate. The student knows that temperature must be controlled, and sets up a beaker to use as a water bath, to control the temperature (CPAC 2c). The student correctly sets up a series of different substrate concentrations and, before adding the enzyme, places her test-tubes in the water bath, the water level rises; so the student then changes this to a larger beaker (CPAC 2b). Observed The worksheet used by the student contains an outline of the experiment. The student decides to investigate temperature as the factor, and plans to ensure that other factors (concentration of substrate, amount of enzyme used) are kept the same (CPAC 2c). Without prompting, he is able to find, in a text book, a suitable method to follow and selects and sets up appropriate apparatus for the experiment (CPAC 2d). When the teacher comes around to check, the student is already collecting data, and his blank results table shows that he is controlling concentration and planning to collect results at 5 different temperatures, using a water bath (CPAC 2c). Although he has planned to collect results every 10 °C, the teacher can see that the current experiment is using a water bath at 29 °C, and the student has already corrected the results table (CPAC 2b). Observed A student breaks a mercury thermometer in the course of an experiment and is seen putting the broken thermometer in a draw. No attempt is made to deal with any spilt mercury. The student continues with his work and does not report the incident to the class teacher. The incident is mentioned to the teacher who then intervenes. The student has failed to minimise risk of harm to himself or others in the class. Observed A student identifies hazards and risks associated with their procedure. His work space is well organised. He works safely and handles equipment confidently and competently. The practical period is completed without incident. Observed A student prepares a detailed (suitable and sufficient) risk assessment covering all aspects of the practical work. The student completes the investigation safely in accordance with laboratory requirements and risk assessment. At all times she works confidently and without need for intervention. Her work space is well organised. She spills a small amount of ethanamide in the fume cupboard but warns those working near her and then reports this to the teacher (laboratory rules specify that spills are to be reported to the teacher who deals with the situation). Students are expected to identify hazards and risks in work. A detailed risk assessment exceeds this requirement. Context Biology (Year 12): Investigation into the effect of exercise on pulse rate. Context Biology (Year 12): Investigation into the effect of exercise on pulse rate. Context Biology (Year 12): Investigation into the effect of exercise on pulse rate. Observed The student starts the investigation without consideration of the impact of the exercise on those participating. One participant has an asthma attack and has to stop and take medication and it is determined, in hindsight, that this individual should not have been asked to exercise. Observed The student asks the individuals participating in the exercise if they have any relevant health concerns. He then proceeds with the investigation without incident once it has been established that no one suffers from a heart or lung condition. Observed The student considers detailed risks and hazards with the investigation, including whether any participant has a relevant health concern and the safety of the exercise to be carried out. One participant is asked not to take part as she has a heart condition. When the participants start the exercise (running up and down a flight of stairs), the student decides that this is actually quite risky as there is more foot traffic in the school than originally anticipated. Therefore, he changes the exercise to a longer period of star jumps on the spot. A detailed risk assessment is provided as part of the investigation. Context Chemistry (Year 12): Finding the concentration of a solution of hydrochloric acid by titration. Context Chemistry (Year 12): Finding the concentration of a solution of hydrochloric acid by titration. Context Chemistry (Year 12): Finding the concentration of a solution of hydrochloric acid by titration. Observed The student reads the worksheet provided, which gives some information on safety for this experiment. The student collects safety glasses, but they spend the majority of the time pushed up on her head – she only pushes them down over her eyes when prompted by her teacher. She turns around to talk to someone else in the laboratory during the practical, and knocks over a conical flask as she turns. She does not notice the spillage. Observed The student looks at the method given, and follows the instructions about correct use of lab coat and safety glasses. He tells his teacher how he attached the pipette filler to the pipette – this method is safe, and the teacher confirms this. Once he has used the pipette, he detaches the filler and puts the pipette somewhere where it will not roll off the lab bench. When he is washing up after the experiment, he accidentally pours some acid on his skin. He washes it off with plenty of water, and then tells his teacher what has happened: no further action is necessary. Observed On being told that the experiment is a titration, the student knows that the safety equipment required will be a lab coat, eye protection and a pipette safety filler. The student is working in a pair, and she reminds her lab partner of the safe method of attaching the pipette filler to the pipette. She remembers all the key points for safely filling a burette, including bringing the burette down to a safe working level before filling. When her teacher asks what she would do in the event of a spillage, she is able to describe a safe method of clearing it away. appeared to draw what she thought should be present. The student was clearly distracted from the task by chatting to her neighbour. No indication of length in eye piece units was given. The candidate forgot to record the magnification of the drawing. taking them. His readings are recorded into suitable tables to an appropriate number of decimal places taking into account the resolution of the apparatus (eg burette readings were to 2 decimal places with second figure as '0' or '5'). On one titre reading he omitted to write down '0'. This appeared to be an oversight by the candidate who recognised his error when it was brought to his attention. significant error. She increased the length of the pendulum of her shortest run in the light of her experience. The candidate then made multiple readings of the period of the pendulum at a total of six lengths approximately evenly spaced over the range she determined. She took period readings for six different lengths. She recorded all information immediately into a suitable table to an appropriate precision with units correctly recorded. Her tables also facilitated the recording of processed data. This is a capable candidate who displays the full range of making and recording skills in one procedure. It is possible that different aspects of these skills could have been demonstrated in more than one experiment. It is not necessary to record processed data – only raw data- in an appropriate table so this candidate has exceeded the standard. Context Biology (Year 12): An investigation into the water potential of potato Observed As part of the investigation, the student is expected to draw an accurate results table. In this case, the student confuses the dependent and independent variables and draws a table where the units are repeated in each line of data. This is pointed out by the teacher in discussion with the student and the student is then able to draw a more suitable table and know the format for the next time this skill is required. Context Biology (Year 12): An investigation into the water potential of potato Observed The student uses a balance to 2 decimal places to weigh and record the mass of her potato chips. The table used has the variables and headings correctly labelled. The student is reminded of the importance of recording all readings at the time of taking them and so does this for all readings after the first one. Context Biology (Year 12): An investigation into the water potential of potato Observed The student records the mass of potato chips accurately using a balance to 2dp and writes them down in a suitable table as they are weighed. The table has all headings and variables correctly labelled but the table is rough and sketched in the student’s lab book. The student then goes on to draw a further table for processed data to include the percentage gain or loss of water of each chip and the mean. This is all recorded correctly. Context Physics (Year 12): Determine the Young modulus of a material. Context Physics (Year 12): Determine the Young modulus of a material. Context Physics (Year 12): Determine the Young modulus of a material. Observed The student takes a measurement of the diameter of the wire, but is not familiar enough with using a micrometer and only takes a single reading. Only two different loads are used in the experiment, so the student simply records two forces and two extensions. It is not clear from the student’s results what the units are for either measurement. Observed The student is competent in the use of the micrometer and reads the scale correctly to record the diameter of the wire. The student keeps a rough table of the mass used in each experiment (in grams) and the extension of the wire (in mm). In the time available, the student collects five* data points. His graph does have an outlier, but he draws a line of best fit and calculates a value for the test wire. The value does not match the data book, but the teacher is confident that the data has been collected as accurately as the apparatus allows and that the correct gradient has been calculated from the graph. *the exact number of data points to meet CPAC 4 may vary from experiment to experiment. Observed The student takes two or three measurements of the diameter of the wire, using the micrometer with accuracy, and calculates a mean value. The student records extension and load, with units, in a suitable table and makes a rough plot of force versus extension as data is collected. The student continues to take readings up to the elastic limit of the test wire. The value that the student calculates does not match the data book value, but the student carries out an error analysis to help explain why the value may not match that in the literature. Context Any subject or Year: Materials Report Observed Student presents information, which may be correct, but without any references or evidence of additional knowledge found from researching. Context Any subject or Year: Materials Report Observed Student has identified a minimum amount of new information relevant to the material being studied and linked it to understanding from teaching. The references do not follow a standard format, but would allow the reader to locate the information. Context Any subject or Year: Materials Report Observed Student has taken the project seriously and researched a wide range of additional data to support how the internal structure of a material lends that material to a particular use. The references follow an accepted pattern and are complete. Context Biology (Year 12): Investigation of plant mineral deficiencies. Observed As part of the preparatory work in advance of the practical, students are asked to undertake some research concerning the Context Biology (Year 12): Investigation of plant mineral deficiencies. Observed As part of the preparatory work in advance of the practical, students are asked to undertake some research concerning the Context Biology (Year 12): Investigation of plant mineral deficiencies. Observed As part of the preparatory work in advance of the practical, students are asked to undertake some research concerning the factors that could be investigated in this investigation. The student’s research is poor: his only source of information is the textbook and, although he has read up on some of the theory, he has not considered how this would affect the practical work to be undertaken. No written record is made by the student to say which sources were used in his research. factors that could be investigated in this investigation. The student uses Wikipedia as a source, along with her textbook, and she writes some notes in her lab book that show some factors that could be investigated. Her written report includes the URL for Wikipedia, along with the data and time accessed; and the title of the textbook used, the author, and the pages from which she obtained the information. When questioned, she acknowledges that Wikipedia is not always a reliable source, but says that the information on the website agreed with her textbook. factors that could be investigated in this investigation. The student writes some notes in his lab book, based on the use of two different websites, and back-up by two different textbooks. All sources used are accurately referenced. He uses these sources to state the main factors, and then goes on to outline a possible plan for the experiment, including some excellent experimental detail on apparatus and quantities.