17.State the dependent variable if you're investigating the effect of temperature on the time taken for iodine to remain yellow.

16.State the independent variable if you're investigating the effect of pH on the time taken for iodine to remain yellow.

20.State a control variable if you're investigating the effect of pH on the time taken for iodine to remain yellow.

Which of the following is the dependent variable?A. TimeB. Purity of waterC. Amount of Alka-SeltzerD. Temperature

Write down what the independent and dependent variables are in this experiment.

. A company has made a new material called ‘Wellwarm’. They want to use ‘Wellwarm’ to make coats. (a) A scientist tested ‘Wellwarm’ to see how well it insulated a beaker of hot water. She tested ‘Wellwarm’ and three other materials as shown below. She wrapped each beaker in a different material. She recorded the temperature at the start and 20 minutes later. (i) What was the independent variable that the scientist changed? (ii) What was the dependent variable that the scientist measured during the investigation? (b) The results of the investigation are shown below. time (minutes) temperature of water (°C) wrapped in material A material B material C material D 0 60 60 60 60 20 34 40 38 36 material A material B material C material D thermometerlidPrimaryTools.co.ukPrimaryTools.co.uk KS3/09/Sc/Tier 3–6/P1 19 Total 8 9c 1 mark 9bii 1 mark 9c 1 mark 9d 1 mark 9e 1 mark (i) The scientist said that the ‘Wellwarm’ material is the best insulator. Which material was ‘Wellwarm’? Use the results to help you. Tick the correct box. (ii) Use the evidence in the results table to explain your choice. (c) The company made a coat from each of the four materials they tested. A person tested the different coats by wearing each one in a cold room. He measured the temperature inside each coat for 30 minutes. Write down two other variables that should be controlled to make this a fair test. 1. 2. (d) Write down one thing the scientists should do to make sure the person testing the coats is safe. (e) Suggest one advantage of using a temperature sensor and data logger instead of a thermometer in this experiment. maximum 8 marks 9bi 1 mark