Jc Aqa Gcse 232 P1a1 3 Pcttn Testing Insulators

P1a 1.3 Practical sheet Teacher notes

Testing sheets of materials as insulators Aims 1 To carry out fair tests to compare different insulation materials. 2 To consolidate previous work on cooling curves and graph plotting. 3 To reinforce understanding about the use of insulating materials.

Teaching notes 1 In Part 1, the temperature of hot water in several identical beakers is measured every minute for at least 20 minutes. Each beaker should be wrapped in a different insulation material. a)

b)

c)

Each group of students is to use a different beaker. The whole class need to agree on how much hot water to have in each beaker. The hot water could be supplied by the teacher using a kettle. A plastic cup could be used to transfer water from the kettle to a plastic measuring cylinder. The students should use the measuring cylinder to ensure there is the same volume of hot water in each beaker. The starting temperature does not need to be exactly the same for each beaker as comparisons can be made using the graph. However, low-attaining students will probably find the comparisons easier if the starting temperature is the same for each beaker. Each beaker should be fitted with a lid as heat loss due to evaporation of water from the beakers will affect the results. Also, each beaker should be on an insulating mat to reduce heat transfer through the base. Timing could continue for more than ten minutes according to how much time is available. Remind students to stir the water between measurements. Each set of measurements should be plotted on a separate graph.

2 In Part 2, the graphs could be pinned on a board so students can discuss how to compare the cooling rates either in terms of the time to cool from a certain temperature to a lower temperature or in terms of the temperature change from a certain temperature in a certain time. Each student can then fill in their own comparison table and draw their own conclusions based on the graphs.

Teaching assistants 1 Low-attaining students will need assistance with the instructions in each part. Remind the students how to use a stopwatch and how to measure the temperature each minute. Remind them not to leave the thermometer (or the measuring cylinder) lying near the edge of the bench and not to reach over the equipment. Increase the size of the work sheets (and graph paper) to A3 if necessary. 2 Ensure practical equipment is safely returned after it has been used. 3 Assist students to plot the measurements on graph paper if necessary.

AQA Science © Nelson Thornes Ltd 2006

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P1a 1.3 Practical sheet Continued …

Safety 1 Ensure students know not to clutter their working space for the practical work with other items. 2 Remind students not to leave thermometers and measuring cylinders near to the edge of the bench or table and not to reach over equipment. 3 Provide paper towels to mop up any spillage of water. 4 Take care with hot water.

AQA Science © Nelson Thornes Ltd 2006

P1a 1.3

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P1a 1.3 Practical sheet Continued …

Technician notes Equipment For each student (or group): • Liquid-in-glass thermometer. • Beaker or can, lid and insulation mat. • Different insulation materials cut to size to fit round each beaker (e.g. thin felt, paper, bubble wrap, thick felt, wool) plus rubber bands or Sellotape to keep the material in place on the beaker. • Stopwatch. • Plastic cup. • Plastic measuring cylinder with the capacity to measure the maximum volume of water in beaker. • Paper towels. • Graph paper for each student. For the whole class: • Kettle to be used by the teacher to supply hot water.

Safety 1 Ensure students know not to clutter their working space for the practical work with other items. 2 Remind students not to leave thermometers and measuring cylinders near to the edge of the bench or table and not to reach over equipment. 3 Provide paper towels to mop up any spillage of water. 4 Take care with hot water.

AQA Science © Nelson Thornes Ltd 2006

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