Activity 4.1 Let us explore Table 4.1 Appearance, hardness, and effect of hammering Class 7

Activity 4.1 Let us explore Class 7

Activity 4.1 Let us explore Class 7

Table 4.1 Appearance, hardness, and effect of hammering on different objects or materials

Answer:

Conclusion:

1. Materials like copper, aluminium and iron are lustrous, hard and can be flattened into thin sheets.
2. Materials like coal, sulfur are nonlustrous, soft and breaks into pieces. Wood is neither malleable nor brittle.

Question 1.

Are all metals hard and solid?

Answer:

No; some metals like sodium and potassium are so soft that they can be cut with a knife.

Question 2.

Which objects did you find become flat on beating with a hammer?

Answer:

The objects such as a piece of copper, an iron nail, and a piece of aluminium become flat when beaten.

Question 3.

Can you give some examples of metal sheets?

Answer:

Some examples of metal sheets are silver foil and aluminium foil.

Question 4.

Where do you find the use of metal wires?

Answer:

We find the wires of metals like copper or aluminium in electrical fittings. Some ornaments, like bangles, necklaces, earrings, etc., are also made from metal wires. Metal wires play important functions in a variety of stringed musical instruments, such as veena, sitar, violin, and guitar.

Question 5.

Have you ever seen wires made of coal or sulfur?

Answer:

No, because coal and sulfur are not ductile.

Question 6.

Have you ever noticed the sound produced when a metal spoon, or a metal plate, or a metal coin is dropped on the floor? How is it different from the sound produced when a piece of coal or wood is dropped on the floor?

Answer:

Yes, the metal spoon and the metal coin produce a ringing sound. Coal and wood, on the other hand, produce dull sounds.