Subject Experts Solutions for Chapter: Materials: Metals and Non-Metals, Exercise 3: TOUGH NUT

Ram was wondering why metals are used for making bells and not wood? Can you explain why?

Often, doctors prescribe iron tablets for weakness. Why are the tablets not as hard as iron? What do iron tablets contain?

Nowadays, silverware blackens faster than it did during our grandparents' time. What do you think could be the reason?

Robert has a fascination for antiques. He likes old furniture, paintings, utensils etc. but antique swords are his most favourite. One day, he got a chance to attend a special session on 'making of swords'. In the session, the lecturer explained everything about the art of making swords-how initially the material for making the sword has to be heated up, then beaten again and again to give it shape, and finally how it has to be cooled in the water and again reshaped. He told that choosing the correct material-something which will not break on beating-is a real challenge. The chosen material will be soft enough to be shaped and yet strong enough to be useful. He explained how different materials were used for making swords during different times and how the materials were improved with time for making better swords. Robert was astonished to hear the complex requirements for making swords.

Name one more metal which is used for making swords in the modern age.

Robert has a fascination for antiques. He likes old furniture, paintings, utensils etc. but antique swords are his most favourite. One day, he got a chance to attend a special session on 'making of swords'. In the session, the lecturer explained everything about the art of making swords-how initially the material for making the sword has to be heated up, then beaten again and again to give it shape, and finally how it has to be cooled in the water and again reshaped. He told that choosing the correct material-something which will not break on beating-is a real challenge. The chosen material will be soft enough to be shaped and yet strong enough to be useful. He explained how different materials were used for making swords during different times and how the materials were improved with time for making better swords. Robert was astonished to hear the complex requirements for making swords.

Name one value that we can learn from the material used for making swords.

Rinku is studying in class 8. The science teacher has announced a practical test. In this test the students will have to test different materials for their qualities and based on the qualities they will have to guess if the material is a metal or not. Rinku conducted the tests and put the findings as follows: 

Sample no 1: malleable, sonorous and a good conductor of electricity 

Sample no 2: non-malleable, non-sonorous and a poor conductor of electricity

Sample no 3: malleable, sonorous and a poor conductor of electricity   

 Rinku is not able to identify these samples as metals or non-metals. She asked her friend Jyothi to help her but jyothi refused.

Can you help Rinku to identify the metals from the above samples?

Rinku is studying in class 8. The science teacher has announced a practical test. In this test the students will have to test different materials for their qualities and based on the qualities they will have to guess if the material is a metal or not. Rinku conducted the tests and put the findings as follows: 

Sample no 1: malleable, sonorous and a good conductor of electricity

Sample no 2: non-malleable, non-sonorous and a poor conductor of electricity 

Sample no 3: malleable, sonorous and a poor conductor of electricity   

Rinku is not able to identify these samples as metals or non-metals. She asked her friend Jyothi to help her but jyothi refused.

Name five metals.

Rinku is studying in class 8. The science teacher has announced a practical test. In this test the students will have to test different materials for their qualities and based on the qualities they will have to guess if the material is a metal or not. Rinku conducted the tests and put the findings as follows: 

Sample no 1: malleable, sonorous and a good conductor of electricity 

Sample no 2: non-malleable, non-sonorous and a poor conductor of electricity

Sample no 3: malleable, sonorous and a poor conductor of electricity 

Rinku is not able to identify these samples as metals or non-metals. She asked her friend Jyothi to help her but jyothi refused.

Do you think Jyothi should have helped Rinku? Give reasons.