CBSE Class 7 Science Advanced Physics Machines and Tools Very Short Answer Questions Set 02

Very Short Answer Questions

Question 26. State whether the following statement is true or false: A multipurpose tool can be used to cut wood.
Answer:
True. A carpenter's hand saw can be fixed in its collet to cut wood.
In simple words: Fit a saw in the collet and it cuts wood.

Teacher's Note:
1. The jobs it can do depend on which tool is fitted.
2. Hand saw, drill bit and file are some options.

Question 27. State whether the following statement is true or false: When the screw used to fix the object between the jaws is rotated in the anti-clockwise direction, both the jaws of the vice move towards each other.
Answer:
False. An anti-clockwise turn loosens the vice, and the movable jaw moves away from the fixed jaw. Also only one jaw moves, not both.
In simple words: Anti-clockwise opens the vice.

Teacher's Note:
1. Clockwise brings the jaws together.
2. Only the movable jaw moves; the fixed jaw is fixed to the table.

Question 28. State whether the following statement is true or false: Poker is used to make the surface of a metal smoother.
Answer:
False. A poker makes holes in metal rods or strips. A file is used to smooth surfaces.
In simple words: A poker pierces; a file smooths.

Teacher's Note:
1. Match each tool with its correct job.
2. Mixing up the poker and the file is a common slip.

Question 29. State whether the following statement is true or false: There are two screws in a vice.
Answer:
True. One screw is used to fix the vice to the table and the other is used to move the movable jaw.
In simple words: One screw clamps the vice to the table and one moves the jaw.

Teacher's Note:
1. Look at Fig. 7.5 to find both screws.
2. Do not forget the clamp screw under the table.

Question 30. To prevent tools from _______, oil is applied.
Answer:
rusting
In simple words: Oil keeps water away from the iron and so stops rust.

Teacher's Note:
1. Rust is a brown layer that weakens iron.
2. Oil or grease is applied to metal tools.

Question 31. _______ is used to cut thin sheets of metal.
Answer:
Tin cutter
In simple words: A tin cutter works like scissors for thin metal.

Teacher's Note:
1. Thick rods are cut with a hack-saw instead.
2. The spring in it reduces the effort.

Question 32. In a vice, screw is rotated in _______ direction to tighten the vice.
Answer:
clockwise
In simple words: Clockwise tightens the vice.

Teacher's Note:
1. Anti-clockwise loosens it.
2. This is the same rule as for ordinary screws.

Question 33. We can tighten or loosen screws by using _______.
Answer:
a screw driver
In simple words: A screw driver turns screws in or out.

Teacher's Note:
1. A carpenter uses it to fix and remove screws.
2. It can also be fitted in the collet of a multipurpose tool.

Question 34. To make a hole in a wooden plank, _______ is fixed in the multipurpose tool.
Answer:
a drill bit
In simple words: A drill bit in the collet drills the hole.

Teacher's Note:
1. Wood needs a drill bit and metal needs a poker.
2. The collet holds the drill bit.

Question 35. Tools used to make articles or to repair them are called _______.
Answer:
workshop tools
In simple words: Workshop tools help to make or repair things.

Teacher's Note:
1. Hammers, dividers and vices are examples.
2. Farm tools are called agricultural tools.

Question 36. Plough which is made up of iron or steel plates is called _______ plough.
Answer:
improvised
In simple words: An iron or steel plough is an improvised plough.

Teacher's Note:
1. It lasts longer than a wooden plough.
2. It also digs deeper.

Question 37. _______ is used to level the surface of the soil.
Answer:
Leveller
In simple words: A leveller flattens the soil.

Teacher's Note:
1. It has a metal strip at the bottom of a heavy wooden frame.
2. It is pulled by bullocks or a tractor.

Question 38. _______ is used to remove weeds in a field.
Answer:
Harrow
In simple words: A harrow rakes the weeds out of the soil.

Teacher's Note:
1. It has many sharp nails.
2. It also levels wet soil.

Question 39. _______ is used to sow the seeds.
Answer:
Seed drill
In simple words: A seed drill drops seeds into the soil in rows.

Teacher's Note:
1. It has a funnel, tubes and small ploughs.
2. It keeps the rows evenly spaced.

Teacher's Note:
1. Use the notes for the parts of each tool.
2. Each option in Column B is used exactly once.