Grade 6 | Science Notes - Machine | Unit-2 | Lesson-3
TEST YOURSELF:
1. Fill in the blanks.
a. Simple machines transfer force from one point to another.
b. Sharp instruments are called wedge.
c. In a screw there are double inclined planes wrapped around a cylinder.
d. A nut cracker is an example of liver.
e. A pulley consists of a circular disc having a groove in it's circumference.
Also Check:
Grade 6 | Science Notes - Measurement | Unit-1 | Lesson-1 (OLD COURSE)
Grade 6 | Science Notes - Force and Motion | Unit-2 | Lesson-2 (OLD COURSE)
Grade 6 | Science Notes - Machine | Unit-2 | Lesson-3 (OLD COURSE)
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2. Tick (✓) the right statements and cross (✕) the wrong ones.
a. A pair of scissors is an example of the wheel and axle. (✕)
b. A pulley has a groove on the rim of the wheel. (✓)
c. It is more difficult to climb a vertical slope than a gentle slope. (✓)
d. A machine increases the rate of doing work. (✓)
e. The force applied in the machine to do work is called effort. (✓)
3. Match the following:
| Jackscrew | inclined plane |
| Axe | wheel and axle |
| Wheel barrow | wedge |
| Door knob | screw |
| Slanted plank of wood | lever |
Answer:
| Jackscrew | screw |
| Axe | wedge |
| Wheel barrow | lever |
| Door knob | wheel and axle |
| Slanted plank of wood | inclined plane |
4. Tick (✓) the correct answer (MCQs).
a. A spoon used to open the lid of a can is:i. a lever (✓)
ii. a screw
iii. a wheel and axel
iv. a wedge
b. A grooved wheel used to lift the water from a well is:
i. a lever
ii. a pulley (✓)
iii. an inclined plane
iv. a wheel and axle
c. We can lift heavy vehicles easily by using:
i. wedge
ii. wheel barrow
iii. pulley
iv. jack screw (✓)
d. A moving bus is in ...... with respect to tree.
i. rest
ii. motion (✓)
iii. random
iv. force
i. lever (✓)
ii. pulley
iii. screw
iv. wheel and axle
i. smaller
ii. larger (✓)
iii. neither large nor small
iv. none of the above
i. lever
ii. inclined plane
iii. pulley
iv. wedge (✓)
5. Write any two differences between:
a. a pulley and a wheel and axle.
| Pulley | Wheel and axle |
| 1. A pulley is a circular disc having a groove at it's circumference. | 1. Wheel and axle is a simple machine where wheel is attached to the axle in such a way that both of them spin on the same axis. |
| 2. The examples of pulley are the bucket of water being lifted from the well, elevators, a crane use a pulley system, a bulldozer use a pulley system, rock climbers use pulley system to climb, etc. | 2. The examples of a wheel and axle are string roller of a kite, spanner, wheel of a sewing machine, knob of a door, screw driver, steering of vehicles, etc. |
| 3. The wheel is free to rotate without the influence of the axle. | 3. The wheel can not rotate without the axle being rotated or vice versa. |
| 4. The force is applied by the rope attached to the wheel of the pulley. | 4. The force can be applied to either the wheel or the axle and can be transferred to the other. |
| 5. Pulley is commonly used to lift load. | 5. Wheel and axle is used to lift heavy loads. |
#What are the differences between a pulley and a wheel and axle?
b. Wedge and Screw.
| Wedge | Screw |
| 1. A wedge is a simple machine that has blunt head at one end and sharp edge to another end. | 1. A screw is a simple machine which consists of double inclined plane wrapped on it's cylindrical surface. |
| 2. The examples of wedge are knife, khukuri, nail, chisel, needle, axe, etc. | 2. The examples of a screw are jackscrew, screw nails, drillers, etc. |
| 3. It is usually made of V shaped hard metal having sharp end and blunt end. | 3. It is usually made of hard metal rod with spiral threads on its' cylindrical body. |
| 4. It is used for splitting or separating the things apart. | 4. It is used to lift vehicles while changing their wheels. |
#What are the differences between a wedge and a screw?
c. scissors and knife.
| Scissor | Knife |
| 1. A scissor is a simple machine that has a rigid, straight or bent bar which can rotate freely about a fixed point called fulcrum. | 1. A knife is a simple machine that has blunt head at one end and sharp edge to another end. |
| 2. The scissor is an example of a simple machine lever. | 2. The knife is an example of a simple machine wedge. |
| 3. Effort is applied at one end to cut things at another end. | 3. Effort is applied on the blunt end and things are cut or split with the other sharp edge. |
| 4. The scissor is less sharper than a knife. | 4. The knife is usually sharper than a scissor. |
#What are the differences between scissors and knife?
6. Write short notes on:
a. Pulley: Pulley is a circular disc having a groove at it's circumference. Pulley may be fixed or movable. Pulley is commonly used to lift load.
#What is pulley? Write it's use.
b. Wheel and axle: Wheel and axle is the simple machine where wheel is attached to axle in such a way that both of them spin on the same axis. The examples of wheel and axle are string roller of a kite, spanner, wheel of a sewing machine, knob of a door, screw driver, steering of vehicles, etc. Wheel and axle is used to lift heavy loads.
c. Lever: Liver is a rigid, straight or bent bar which is able to rotate about a fixed point called fulcrum. The examples of lever are see-saw, shovel, bottle opener, scissors, wheelbarrow, nut cracker, etc.
#What is a lever?
d. Inclined plane: A slanted surface made by a plank of wood or metal sheet is called an inclined plane. Inclined plane makes our work easier by magnifying force. The examples of inclined planes are winding roads on hills, staircases, ladders, etc.
7. Give reasons:
a. It is more difficult to climb a vertical staircase than a slanted one. Why?
Answer: It is more difficult to climb a vertical staircase than a slanted one because more effort is required to climb vertical staircase and less effort is required for slanted one.
b. A pulley used in a well helps us in pulling out water. Why?
Answer: A pulley used in a well helps us in pulling out water because it makes our work easier by changing the direction of force applied.
c. A pair of scissors is a simple machine. Why?
Answer: A pair of scissors is a simple machine because it helps us to cut papers, things, etc. by applying little force and make our work easier and convenient.
d. A simple machine makes our work easier and faster. Why?
Answer: A simple machine makes our work easier and faster because it change the direction of force applied, magnifies the force and increase the speed of the force.
e. Wedge is important in our daily life. Why?
Answer: We all do work and use simple machines to make work easier in our daily life. The wedge (knife, an axe, saw, a needle, sickle, etc.) is a simple machine which we use in our daily life to separate things or an object apart. So, simple machine - wedge is important in our daily life.
8. Answer the following questions.
a. What is simple machine? Give any two examples.
Answer: The device which is used in our daily life to make our work easier, faster and more convenient is called a simple machine. The two examples of simple machine are see-saw and knife.
b. Enlist the different types of simple machines used at your house.
Answer: The different types of simple machines used at our house are:-
i. axe.
ii. screw driver.
iii. shovel.
iv. broom.
v. scissors.
vi. knife.
vii. beam balance.
viii. hammer.
ix. bottle opener.
x. ladders.
xi. staircases.
xii. khukuri.
xiii. chisel.
xiv. needle.
xv. nail.
xvi. knob of a door.
xvii. nut cracker.
xviii. a doorstop.
xix. nail clipper.
xx. tweezers.
xxi. a can opener.
xxii. a pair of pliers.
xxiii. wrench.
xxiv. window latch.
xxv. water tap.
# 25 simple machines used in our house.
c. In how many ways do simple machines make our work easier?
Answer: The simple machines make our work easier by following four ways:
i. Simple machines magnify the applied force.
ii. Simple machines increase the speed of doing work.
iii. Simple machines change the direction of force.
iv. Simple machines transfer force from one point to another point.
d. How can a simple machine lift a heavy load with small effort?
Answer: A simple machine can lift a heavy load with small effort by magnifying force. For example, a crowbar is used to turn over a big stone easily as the crowbar enables us to multiply the applied effort or force.
e. Define pulley. What is the use of a pulley?
Answer: Pulley is a circular disc having a groove at it's circumference. Pulley may be fixed or movable. The use of a pulley is to lift load.
f. How does wheel and axle work?
Answer: In wheel and axle, wheel is attached to axle in such a way that both of them spin on the same axis. So, the effort is applied into the wheel and they work jointly.
g. For what purpose are the inclined planes used? Write the similarity between an inclined plane and a screw.
Answer: Inclined planes are used to pull or push heavy loads by applying little effort. The similarity between an inclined plane and a screw is that an inclined plane makes work easier by breaking an upward or downward movement into smaller increments and a screw is like an inclined plane wrapped around a cylinder.
h. What is wheel and axle? Write it's use.
Answer: Wheel and axle is the simple machine where wheel is attached to axle in such a way that both of them spin on the same axis. Wheel and axle is used in lifting heavy loads, moving people quickly, moving parts of complex machine, lifting water buckets from well, etc.
i. What is wedge? Write it's use.
Answer: A wedge is a simple machine that has blunt head at one end and sharp edge to another end. Wedge is used in splitting or separating the things apart and lift an object or hold an object in place.
j. What is jackscrew? Where is it used?
Answer: Jackscrew is a simple machine which consists of double inclined plane wrapped on it's cylindrical surface. Jackscrew is used in lifting heavy weights, such as vehicles while changing their wheels and adjustable supports for heavy loads like foundation of houses.
Extra Question Answers:
k. What are the six different types of simple machines?
Answer: The six different types of simple machines are-
i. Lever,
ii. Wheel and axle,
iii. Pulley,
iv. Inclined plane,
v. Screw,
vi. Wedge.
l. What is fulcrum?
The fixed point from where the lever rotates freely is called fulcrum.
m. What is effort?
Answer: The force applied by the machine to do work is called effort.
n. What is load?
Answer: The force applied by the machine is called load.
o. What is load distance (Ld)?
Answer: The distance between the fulcrum and the load is called load distance (Ld).
p. What is effort distance (Ed)?
Answer: The distance between the fulcrum and effort is called effort distance (Ed).
q. What is a screw?
Answer: A screw is a cylinder having double inclined planes wrapped around the cylinder.
r. Name some simple machines and their use in our daily life.
Answer: The name of some simple machines and their use in our daily life are given below:
i. Axe is used to chop firewood.
ii. Screwdriver is used to unbolt a nut.
iii. Crowbar is used to lift a load.
iv. Wheel barrow is used to carry loads like bricks.
v. Bottle opener is used to open the lid of a bottle.
vi. Shovel is used to lift and throw the soil.
vii. Knife is used to cut vegetables.
viii. Pulley is used to lift heavy loads.
ix. Beam balance is used to measure the mass of substance.
x. Scissor is used to cut hair, paper, clothes, etc.
9. Diagrammatic questions:
a. Sketch a figure of each of the following:
i. wheel and axle
ii. fixed and movable pulleys
iii. third class lever
iv. screw nail
b. Two methods of using a crowbar are shown in the figures below. Study them and answer the following questions:
i. In which lever, work can be done fast?
Answer: In lever i. fig, work can be done fast.
ii. In which lever, load can be lifted by using less force?
Answer: In lever i. fig, load can be lifted by using less force.
c. Study the given figures and label the positions of load, effort and fulcrum in each.
d. Answer the following questions on the basis of the above diagrams.
i. Name any two levers which increases the speed of doing work.
ii. Name any two levers which magnify force.
iii. Name any two levers in which the direction of force is changed.
e. Answer the following questions with the help of the given figures.
i. Which type of simple machines are shown in (i) and (ii).
ii. Which one of the above simple machine has more advantages? Why?
iii. Which inclined machine can lift a load easily?
GLOSSARY:
Rigid: very strong and difficult to change (#rigid meaning in nepali language is साह्रो, कडा, कठोर, स्थीर)
Knob: a round handle-like structure (#knob meaning in nepali language is ढोकाको बिंड, उभार)
Steering: the machinery of a vehicle, used to control the direction it goes in (#steering meaning in nepali language is स्टेरिङ, स्टीयरिंग)
Groove: a long narrow cut in the surface of something hard (#groove meaning in nepali language is खोपिल्टो, नाली)
Drillers: the device used to drill a hole (#drillers meaning in nepali language is प्वाल पार्ने मेसिन)
Plank: a long narrow flat piece of wood (#plank meaning in nepali language is फलियो, काष्ठफलक, सिपू)
#From above grade class-6 science notes of "Machine" Unit-2, Lesson-3, we hope students will be able to:
- Define simple machines.
- List the ways by which simple machines make work easier.
- Write about various simple machines with examples briefly.
- Sort out the different types of simple machines.
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