Answer all questions in the spaces provided 0 1 Metals are good thermal conductors 0 1. 1 Complete the sentence. Choose the answer from the box. [1 mark] electrons ions neutrons protons Metals are good thermal conductors because they contain free A student investigated the rate of thermal conduction in metal rods. Each rod was made from a different metal. A pin was attached to the end of each metal rod with wax. Figure 1 shows some of the equipment used Figure 1 Metal rod Pin- Wax Tripod -Bunsen burnerThe student placed a Bunsen burner under one end of the metal rods and started a stopwatch. As the other end of each metal rod heated up, the wax melted and the pin dropped The student recorded the time at which each pin dropped. 0 1. 2 What is one control variable in the investigation? [1 mark] Tick ( ) one box. The length of the metal rods The metal that each rod is made from The time at which each pin dropped 0 1. 3 The student wore safety glasses during the investigation. Give one other safety precaution that the student should take when carrying out the investigation. [1 mark]Table 1 shows the results. Table 1 Metal Time at which the pin dropped in seconds Aluminium 35 Copper 20 Iron 45 Tin 52 0 1. 4 Which metal is the best thermal conductor? Use Table 1 (1 mark] Tick ( ) one box. Aluminium Copper Iron Tin 0 1. 5 The student repeated the investigation with a hotter flame from the Bunsen burner. Give one similarity and one difference between the results that the student would observe and the results in Table 1. [2 marks] Similarity Difference [Total 6 marks]