Materials Metals and Plastics (Class 8)

What this worksheet covers

This is an eighteen-question practice worksheet on materials — metals, non-metals and synthetic fibres for Class 8, written to the pattern of the SOF National Science Olympiad (NSO). It carries 24 marks and is designed to be attempted in 45 minutes, split across three sections — Scientific Reasoning, Applying What You Know and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on materials — metals, non-metals and synthetic fibres at Class 8 level
• Working accurately against a time limit, as the real paper demands
• Scientific Reasoning questions in the olympiad format
• Applying What You Know questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 18 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–15 carry 1 mark each. Questions 16–18 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Study every diagram and table carefully.

Sample questions from this worksheet

A preview of what's inside Materials Metals and Plastics (Class 8) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. Which of these is a non-metal that conducts electricity?

   • AGraphitecorrect
   • BSulphur
   • CPhosphorus
   • DIodine
   Solution: Graphite, a form of carbon, is the one common non-metal that conducts electricity well. This is why it is used for the electrodes in dry cells.

2. 2. An iron nail is dipped in copper sulphate solution. After some time the blue colour fades and the nail turns brownish. Why?

   • AIron dissolves without reacting
   • BCopper is more reactive than iron
   • CIron is more reactive than copper, so it displaces copper from the solutioncorrect
   • DThe solution evaporates
   Solution: Iron is more reactive than copper, so it displaces copper from copper sulphate solution. Iron sulphate (pale green) forms and a reddish-brown deposit of copper settles on the nail, while the blue colour fades.

3. 3. Consider the following statements.(i) All metals are solid at room temperature.(ii) Non-metal oxides are generally acidic.(iii) Thermosetting plastics can be remoulded on heating.Which of the statements is/are correct?

   • A(i) only
   • B(ii) onlycorrect
   • C(i) and (ii) only
   • D(ii) and (iii) only
   Solution: Statement (i) is false — mercury is a liquid metal. Statement (ii) is true; sulphur dioxide dissolved in water turns blue litmus red. Statement (iii) is false; it is thermoplastics that can be remoulded, while thermosetting plastics set permanently. Hence (ii) only.