class 8 scoence activity 4.6
Answers
Answer:
Observation:
We observe that the nail flattens and become thin.
Explanation:
Metals are malleable, that means they can be shaped into thin sheets. When we strike the hammer the shape of the email changes and becomes flat.
Non-metals like coal and pencil lead are brittle and fragile. When we strike them with a hammer, they don’t flatten and shatter into pieces.
Activity solution Chapter 4 Class 8 ScienceInference: Metals are malleable while non-metals are brittle.
Application:
Kitchen utensils made of aluminium and other metal are made using this property.
Thin aluminium foils which are used to wrap food is a very thin sheet of aluminium. It is made by beating the aluminium.
See also: Activity solution Chapter 3 Synthetic fibres and plastics
Answer:
We observe that the nail flattens and become thin.
Explanation:
Metals are malleable, that means they can be shaped into thin sheets. When we strike the hammer the shape of the email changes and becomes flat.
Non-metals like coal and pencil lead are brittle and fragile. When we strike them with a hammer, they don’t flatten and shatter into pieces.
Activity solution Chapter 4 Class 8 ScienceInference: Metals are malleable while non-metals are brittle.
Application:
Kitchen utensils made of aluminium and other metal are made using this property.
Thin aluminium foils which are used to wrap food is a very thin sheet of aluminium. It is made by beating the aluminium.
See also: Activity solution Chapter 3 Synthetic fibres and plastics
Activity 4.2
Activity 4.2 has given a list of some common metals and non-metals. It asks us to check whether they conduct electricity or not.
Observation:
Iron and copper wire conduct electricity while coal and sulphur do not conduct electricity.
Explanation:
Materials: Metals and Non-metals Activity solution Chapter 4 Class 8 Science
Metals have free electrons in their outer shells. When we connect metal with battery these electrons move. As a result, metals are a good conductor of electricity.
Non-metals do not have free electrons in their outer shell. So, they do not conduct electricity.
Inference/Conclusion:
Metals are good conductor of electricity while non-metals do not conduct electricity.
Application:
Rubber gloves are a very bad conductor of electricity. So, an electrician uses these gloves to avoid any electrocution
Activity 4.3
Activity 4.3 asks us to dissolve some rusted iron into water and know if the solution is acidic o basic.
activity 4.3 class 8 scienceObservation:
The solution turns red litmus paper to blue.
Explanation:
Rust of iron is an oxide of iron. The metal oxide forms its hydroxide with water. As a result, they make the solution basic which turns the red litmus blue.
Fe2O + 6H2O → 2Fe(OH)3 + 3H2