Textbook: Simple Machines | General Science Class 6 (Maharashtra Board) PDF Download

 Page 1


84
Such devices which are used 
to get more work done in less 
time and less effort are called 
machines.
The nail cutter, the bottle 
opener, the wheel used to push 
the load shown in the picture are 
all machines. They have only one 
or two parts and a simple and 
easy structure. Such machines are 
called simple machines. Simple 
machines can be handled easily, 
and there are less chances of 
these  machines breaking down 
or getting damaged. We use many 
such machines in  our day-to-day 
life. 
Observe the machines shown in the following pictures. For what 
purposes are they used ? Can you name some other machines 
of this kind?
These machines have 
many parts which carry out 
many processes for completing 
a task. For this purpose, the 
parts are joined to one another. 
Therefore, these machines are 
called complex machines. 
Some of the parts of such 
complex machines are actually 
simple machines. The structure 
of complex machines is 
complicated.
In our day-to-day life, we use simple or complex machines depending upon the task 
to be carried out and the time and efforts required to do it.
12.2 : Various machines
12. Simple Machines
Observe and discuss.
Can you tell ?    
In the following pictures, certain devices are used to 
accomplish certain tasks more easily. Name the devices 
and discuss how they help.
12.1 : Various kinds of tasks
Page 2


84
Such devices which are used 
to get more work done in less 
time and less effort are called 
machines.
The nail cutter, the bottle 
opener, the wheel used to push 
the load shown in the picture are 
all machines. They have only one 
or two parts and a simple and 
easy structure. Such machines are 
called simple machines. Simple 
machines can be handled easily, 
and there are less chances of 
these  machines breaking down 
or getting damaged. We use many 
such machines in  our day-to-day 
life. 
Observe the machines shown in the following pictures. For what 
purposes are they used ? Can you name some other machines 
of this kind?
These machines have 
many parts which carry out 
many processes for completing 
a task. For this purpose, the 
parts are joined to one another. 
Therefore, these machines are 
called complex machines. 
Some of the parts of such 
complex machines are actually 
simple machines. The structure 
of complex machines is 
complicated.
In our day-to-day life, we use simple or complex machines depending upon the task 
to be carried out and the time and efforts required to do it.
12.2 : Various machines
12. Simple Machines
Observe and discuss.
Can you tell ?    
In the following pictures, certain devices are used to 
accomplish certain tasks more easily. Name the devices 
and discuss how they help.
12.1 : Various kinds of tasks
85
Let us learn about some simple machines. 
An inclined plane
A heavy drum is to be loaded onto a truck. 
Ravi chose the plank A while Hamid chose the 
plank B. Rahi did not use a plank at all.
1. Who would find the drum heaviest to load ?
2. Who would find it lightest ?
Which one of the planks A and B is longer  ?
Which one has a steeper slope ? 
What can we conclude from this ?
If a slanting plank is used to lift a weight, we 
have to bear less of the weight and lifting it becomes 
easier. Such a plank is called an ‘inclined plane’. 
The more gradual the slope, the lesser is the weight 
we bear. But, such an inclined plane is longer. The 
steeper the slope, the shorter the inclined plane. But 
we have to bear a greater weight. 
12.3 : Loading a drum onto a truck
Cut out a triangular piece of paper ABC. 
Draw a red line along the edge AC. Roll 
this paper around a pencil as shown in the 
picture. What do you see ?
The inclined side AC of the triangle 
descends gradually from A to C. 
The threads on a screw are made in 
the same way. That is why, when a screw 
is fitted in wood it goes in as if it is going 
down an inclined plane. Therefore, less force 
is required to fit a screw than to hammer a 
nail. In other words, a screw is  like a rolled 
up inclined plane made of an iron strip.
A winding road or ghat that goes up 
a mountain is also like an inclined plane 
wrapped around the mountain. It helps big 
vehicles to climb up and down the mountain 
easily. 
12.4 : The screw as an inclined plane
Two routes, namely, a pathway and a 
road are available to climb the mountain 
shown in the picture. Compare the time and 
strength and your convenience required to  
reach the mountain top. 
12.5 : Ghat
A
C B
Let’s try this.
Observe and discuss.
A
B
Page 3


84
Such devices which are used 
to get more work done in less 
time and less effort are called 
machines.
The nail cutter, the bottle 
opener, the wheel used to push 
the load shown in the picture are 
all machines. They have only one 
or two parts and a simple and 
easy structure. Such machines are 
called simple machines. Simple 
machines can be handled easily, 
and there are less chances of 
these  machines breaking down 
or getting damaged. We use many 
such machines in  our day-to-day 
life. 
Observe the machines shown in the following pictures. For what 
purposes are they used ? Can you name some other machines 
of this kind?
These machines have 
many parts which carry out 
many processes for completing 
a task. For this purpose, the 
parts are joined to one another. 
Therefore, these machines are 
called complex machines. 
Some of the parts of such 
complex machines are actually 
simple machines. The structure 
of complex machines is 
complicated.
In our day-to-day life, we use simple or complex machines depending upon the task 
to be carried out and the time and efforts required to do it.
12.2 : Various machines
12. Simple Machines
Observe and discuss.
Can you tell ?    
In the following pictures, certain devices are used to 
accomplish certain tasks more easily. Name the devices 
and discuss how they help.
12.1 : Various kinds of tasks
85
Let us learn about some simple machines. 
An inclined plane
A heavy drum is to be loaded onto a truck. 
Ravi chose the plank A while Hamid chose the 
plank B. Rahi did not use a plank at all.
1. Who would find the drum heaviest to load ?
2. Who would find it lightest ?
Which one of the planks A and B is longer  ?
Which one has a steeper slope ? 
What can we conclude from this ?
If a slanting plank is used to lift a weight, we 
have to bear less of the weight and lifting it becomes 
easier. Such a plank is called an ‘inclined plane’. 
The more gradual the slope, the lesser is the weight 
we bear. But, such an inclined plane is longer. The 
steeper the slope, the shorter the inclined plane. But 
we have to bear a greater weight. 
12.3 : Loading a drum onto a truck
Cut out a triangular piece of paper ABC. 
Draw a red line along the edge AC. Roll 
this paper around a pencil as shown in the 
picture. What do you see ?
The inclined side AC of the triangle 
descends gradually from A to C. 
The threads on a screw are made in 
the same way. That is why, when a screw 
is fitted in wood it goes in as if it is going 
down an inclined plane. Therefore, less force 
is required to fit a screw than to hammer a 
nail. In other words, a screw is  like a rolled 
up inclined plane made of an iron strip.
A winding road or ghat that goes up 
a mountain is also like an inclined plane 
wrapped around the mountain. It helps big 
vehicles to climb up and down the mountain 
easily. 
12.4 : The screw as an inclined plane
Two routes, namely, a pathway and a 
road are available to climb the mountain 
shown in the picture. Compare the time and 
strength and your convenience required to  
reach the mountain top. 
12.5 : Ghat
A
C B
Let’s try this.
Observe and discuss.
A
B
86
A wedge
An axe is used for cutting wood. A sharp tool is 
formed on joining two inclined planes. Such a tool is 
called a wedge. A wedge in used for breaking an object 
into two pieces or to seperate objects stuck together. 
An axe, a knife or a chisel are some examples of this 
simple machine.
A needle and a nail are also kinds of wedges.
A lever
A farmer is using a strong crow-bar to remove 
the big stone bogged down in the farm. Such a 
machine is called a lever.
A lever has three parts, namely, effort, load 
and fulcrum.
 1. The support at which the rod of a lever is 
rested is called the ‘fulcrum of a lever’. The 
lever rotates about the fulcrum.
 2. The weight lifted by a lever or the force 
against which the lever acts is called the 
‘load’. The arm of the lever from the 
fulcrum to the load is called the ‘load arm’.
12.6 : Wedges
12.7 : Removing a large stone
A needle is required for stitching cloth. We use a 
knife for cutting fruit. If the tip of a needle or the 
In the past...
The Greek scientist Archimedes 
invented the machine shown in this 
picture. That is why, it is called the 
Archimedes’ Screw. It was used to 
lift water from the hold of a ship. 
Archimedes used a round pipe fitted 
with a rod inside it. The pipe was 
placed at an angle of 45
0
 with one end 
inside the water and the rod resting 
on a flat surface. When the rod was 
turned, water got lifted in this device.
Archimedes’ screw
 3. The force applied on the other end of the rod to lift the load is called the 
‘effort’. The part of the lever from the fulcrum to the effort is called the ‘effort 
arm’.
Use your brain power !
Which tasks can be done using 
a lever ?
Use your brain power !
edge of a knife becomes blunt, then the needle does not penetrate the cloth and the 
knife does not cut into the fruit. Why is this so ?
Page 4


84
Such devices which are used 
to get more work done in less 
time and less effort are called 
machines.
The nail cutter, the bottle 
opener, the wheel used to push 
the load shown in the picture are 
all machines. They have only one 
or two parts and a simple and 
easy structure. Such machines are 
called simple machines. Simple 
machines can be handled easily, 
and there are less chances of 
these  machines breaking down 
or getting damaged. We use many 
such machines in  our day-to-day 
life. 
Observe the machines shown in the following pictures. For what 
purposes are they used ? Can you name some other machines 
of this kind?
These machines have 
many parts which carry out 
many processes for completing 
a task. For this purpose, the 
parts are joined to one another. 
Therefore, these machines are 
called complex machines. 
Some of the parts of such 
complex machines are actually 
simple machines. The structure 
of complex machines is 
complicated.
In our day-to-day life, we use simple or complex machines depending upon the task 
to be carried out and the time and efforts required to do it.
12.2 : Various machines
12. Simple Machines
Observe and discuss.
Can you tell ?    
In the following pictures, certain devices are used to 
accomplish certain tasks more easily. Name the devices 
and discuss how they help.
12.1 : Various kinds of tasks
85
Let us learn about some simple machines. 
An inclined plane
A heavy drum is to be loaded onto a truck. 
Ravi chose the plank A while Hamid chose the 
plank B. Rahi did not use a plank at all.
1. Who would find the drum heaviest to load ?
2. Who would find it lightest ?
Which one of the planks A and B is longer  ?
Which one has a steeper slope ? 
What can we conclude from this ?
If a slanting plank is used to lift a weight, we 
have to bear less of the weight and lifting it becomes 
easier. Such a plank is called an ‘inclined plane’. 
The more gradual the slope, the lesser is the weight 
we bear. But, such an inclined plane is longer. The 
steeper the slope, the shorter the inclined plane. But 
we have to bear a greater weight. 
12.3 : Loading a drum onto a truck
Cut out a triangular piece of paper ABC. 
Draw a red line along the edge AC. Roll 
this paper around a pencil as shown in the 
picture. What do you see ?
The inclined side AC of the triangle 
descends gradually from A to C. 
The threads on a screw are made in 
the same way. That is why, when a screw 
is fitted in wood it goes in as if it is going 
down an inclined plane. Therefore, less force 
is required to fit a screw than to hammer a 
nail. In other words, a screw is  like a rolled 
up inclined plane made of an iron strip.
A winding road or ghat that goes up 
a mountain is also like an inclined plane 
wrapped around the mountain. It helps big 
vehicles to climb up and down the mountain 
easily. 
12.4 : The screw as an inclined plane
Two routes, namely, a pathway and a 
road are available to climb the mountain 
shown in the picture. Compare the time and 
strength and your convenience required to  
reach the mountain top. 
12.5 : Ghat
A
C B
Let’s try this.
Observe and discuss.
A
B
86
A wedge
An axe is used for cutting wood. A sharp tool is 
formed on joining two inclined planes. Such a tool is 
called a wedge. A wedge in used for breaking an object 
into two pieces or to seperate objects stuck together. 
An axe, a knife or a chisel are some examples of this 
simple machine.
A needle and a nail are also kinds of wedges.
A lever
A farmer is using a strong crow-bar to remove 
the big stone bogged down in the farm. Such a 
machine is called a lever.
A lever has three parts, namely, effort, load 
and fulcrum.
 1. The support at which the rod of a lever is 
rested is called the ‘fulcrum of a lever’. The 
lever rotates about the fulcrum.
 2. The weight lifted by a lever or the force 
against which the lever acts is called the 
‘load’. The arm of the lever from the 
fulcrum to the load is called the ‘load arm’.
12.6 : Wedges
12.7 : Removing a large stone
A needle is required for stitching cloth. We use a 
knife for cutting fruit. If the tip of a needle or the 
In the past...
The Greek scientist Archimedes 
invented the machine shown in this 
picture. That is why, it is called the 
Archimedes’ Screw. It was used to 
lift water from the hold of a ship. 
Archimedes used a round pipe fitted 
with a rod inside it. The pipe was 
placed at an angle of 45
0
 with one end 
inside the water and the rod resting 
on a flat surface. When the rod was 
turned, water got lifted in this device.
Archimedes’ screw
 3. The force applied on the other end of the rod to lift the load is called the 
‘effort’. The part of the lever from the fulcrum to the effort is called the ‘effort 
arm’.
Use your brain power !
Which tasks can be done using 
a lever ?
Use your brain power !
edge of a knife becomes blunt, then the needle does not penetrate the cloth and the 
knife does not cut into the fruit. Why is this so ?
87
12.8 :  Lifting a paperweight
less force is required to lift the paperweight. Such a 
lever is called a lever of the first order. 
2. The picture shows how we use an opener to remove 
the cap of a sauce bottle. Try to do the same yourself. 
To remove the tight-fitting cap, the opener is rested 
on the cap and we apply a force on the opposite end 
of the opener to pull it upwards. The cap also gets 
pulled up as the opener rotates about the fulcrum. 
Where are the fulcrum, load and effort in this case ? 
3. How do we lift an object using tongs ?   
The weight or the load is at one end of the arms 
of the tongs. We apply effort in the middle of the 
arms. It means the effort is applied in the middle of 
the lever, while the fulcrum and the load are at the 
opposite ends.
There are three types of levers depending upon 
the positions of the effort, the fulcrum and the load.
Lever of the first order
The fulcrum is in the 
centre, the load is at one 
end while the effort is at 
the other end.
Lever of the second order
The load is in the centre, 
the fulcrum on one side, 
and the effort, on the other 
side.
12.10 : Picking up an object
Lever of the third order
The effort is in the centre, 
the fulcrum on one side, 
and the load on the other 
side.
Effort
Fulcrum
Load 
Load Load 
Fulcrum
Now, go on increasing the distance 
between the paperweight and the pencil by 
four centimetres every time and see whether 
the paperweight can be lifted when placed at 
each of those distances. 
What do you find ?
As the effort arm becomes longer and 
longer compared to the load arm, less and 
Load
Fulcrum
Effort
1. Place a pencil on a table. Place a ruler on it at right angles 
with it. Put a paperweight on one end of the ruler. Press the 
other end with your finger to lift the weight. Which are the 
load arm, the effort arm and the fulcrum of this lever ?
Let’s try this .
Load
Fulcrum Effort
Effort
12.9 : Removing the lid
Effort
Load
Fulcrum
Effort
Fulcrum
Effort
Page 5


84
Such devices which are used 
to get more work done in less 
time and less effort are called 
machines.
The nail cutter, the bottle 
opener, the wheel used to push 
the load shown in the picture are 
all machines. They have only one 
or two parts and a simple and 
easy structure. Such machines are 
called simple machines. Simple 
machines can be handled easily, 
and there are less chances of 
these  machines breaking down 
or getting damaged. We use many 
such machines in  our day-to-day 
life. 
Observe the machines shown in the following pictures. For what 
purposes are they used ? Can you name some other machines 
of this kind?
These machines have 
many parts which carry out 
many processes for completing 
a task. For this purpose, the 
parts are joined to one another. 
Therefore, these machines are 
called complex machines. 
Some of the parts of such 
complex machines are actually 
simple machines. The structure 
of complex machines is 
complicated.
In our day-to-day life, we use simple or complex machines depending upon the task 
to be carried out and the time and efforts required to do it.
12.2 : Various machines
12. Simple Machines
Observe and discuss.
Can you tell ?    
In the following pictures, certain devices are used to 
accomplish certain tasks more easily. Name the devices 
and discuss how they help.
12.1 : Various kinds of tasks
85
Let us learn about some simple machines. 
An inclined plane
A heavy drum is to be loaded onto a truck. 
Ravi chose the plank A while Hamid chose the 
plank B. Rahi did not use a plank at all.
1. Who would find the drum heaviest to load ?
2. Who would find it lightest ?
Which one of the planks A and B is longer  ?
Which one has a steeper slope ? 
What can we conclude from this ?
If a slanting plank is used to lift a weight, we 
have to bear less of the weight and lifting it becomes 
easier. Such a plank is called an ‘inclined plane’. 
The more gradual the slope, the lesser is the weight 
we bear. But, such an inclined plane is longer. The 
steeper the slope, the shorter the inclined plane. But 
we have to bear a greater weight. 
12.3 : Loading a drum onto a truck
Cut out a triangular piece of paper ABC. 
Draw a red line along the edge AC. Roll 
this paper around a pencil as shown in the 
picture. What do you see ?
The inclined side AC of the triangle 
descends gradually from A to C. 
The threads on a screw are made in 
the same way. That is why, when a screw 
is fitted in wood it goes in as if it is going 
down an inclined plane. Therefore, less force 
is required to fit a screw than to hammer a 
nail. In other words, a screw is  like a rolled 
up inclined plane made of an iron strip.
A winding road or ghat that goes up 
a mountain is also like an inclined plane 
wrapped around the mountain. It helps big 
vehicles to climb up and down the mountain 
easily. 
12.4 : The screw as an inclined plane
Two routes, namely, a pathway and a 
road are available to climb the mountain 
shown in the picture. Compare the time and 
strength and your convenience required to  
reach the mountain top. 
12.5 : Ghat
A
C B
Let’s try this.
Observe and discuss.
A
B
86
A wedge
An axe is used for cutting wood. A sharp tool is 
formed on joining two inclined planes. Such a tool is 
called a wedge. A wedge in used for breaking an object 
into two pieces or to seperate objects stuck together. 
An axe, a knife or a chisel are some examples of this 
simple machine.
A needle and a nail are also kinds of wedges.
A lever
A farmer is using a strong crow-bar to remove 
the big stone bogged down in the farm. Such a 
machine is called a lever.
A lever has three parts, namely, effort, load 
and fulcrum.
 1. The support at which the rod of a lever is 
rested is called the ‘fulcrum of a lever’. The 
lever rotates about the fulcrum.
 2. The weight lifted by a lever or the force 
against which the lever acts is called the 
‘load’. The arm of the lever from the 
fulcrum to the load is called the ‘load arm’.
12.6 : Wedges
12.7 : Removing a large stone
A needle is required for stitching cloth. We use a 
knife for cutting fruit. If the tip of a needle or the 
In the past...
The Greek scientist Archimedes 
invented the machine shown in this 
picture. That is why, it is called the 
Archimedes’ Screw. It was used to 
lift water from the hold of a ship. 
Archimedes used a round pipe fitted 
with a rod inside it. The pipe was 
placed at an angle of 45
0
 with one end 
inside the water and the rod resting 
on a flat surface. When the rod was 
turned, water got lifted in this device.
Archimedes’ screw
 3. The force applied on the other end of the rod to lift the load is called the 
‘effort’. The part of the lever from the fulcrum to the effort is called the ‘effort 
arm’.
Use your brain power !
Which tasks can be done using 
a lever ?
Use your brain power !
edge of a knife becomes blunt, then the needle does not penetrate the cloth and the 
knife does not cut into the fruit. Why is this so ?
87
12.8 :  Lifting a paperweight
less force is required to lift the paperweight. Such a 
lever is called a lever of the first order. 
2. The picture shows how we use an opener to remove 
the cap of a sauce bottle. Try to do the same yourself. 
To remove the tight-fitting cap, the opener is rested 
on the cap and we apply a force on the opposite end 
of the opener to pull it upwards. The cap also gets 
pulled up as the opener rotates about the fulcrum. 
Where are the fulcrum, load and effort in this case ? 
3. How do we lift an object using tongs ?   
The weight or the load is at one end of the arms 
of the tongs. We apply effort in the middle of the 
arms. It means the effort is applied in the middle of 
the lever, while the fulcrum and the load are at the 
opposite ends.
There are three types of levers depending upon 
the positions of the effort, the fulcrum and the load.
Lever of the first order
The fulcrum is in the 
centre, the load is at one 
end while the effort is at 
the other end.
Lever of the second order
The load is in the centre, 
the fulcrum on one side, 
and the effort, on the other 
side.
12.10 : Picking up an object
Lever of the third order
The effort is in the centre, 
the fulcrum on one side, 
and the load on the other 
side.
Effort
Fulcrum
Load 
Load Load 
Fulcrum
Now, go on increasing the distance 
between the paperweight and the pencil by 
four centimetres every time and see whether 
the paperweight can be lifted when placed at 
each of those distances. 
What do you find ?
As the effort arm becomes longer and 
longer compared to the load arm, less and 
Load
Fulcrum
Effort
1. Place a pencil on a table. Place a ruler on it at right angles 
with it. Put a paperweight on one end of the ruler. Press the 
other end with your finger to lift the weight. Which are the 
load arm, the effort arm and the fulcrum of this lever ?
Let’s try this .
Load
Fulcrum Effort
Effort
12.9 : Removing the lid
Effort
Load
Fulcrum
Effort
Fulcrum
Effort
88
Take a pencil, some sticking tape, an empty reel 
of thread, half a metre of thick thread, a weight such 
as an eraser that can be tied to the thread, play dough.
Place the pencil on the table so that it juts over the 
edge of the table. Fix it firmly to the table using the 
sticking tape. Insert the reel over the part of the pencil 
that juts out. Put a lump of the play dough on the tip 
of the pencil so that the reel does not come off. Draw 
the thick thread having the weight at one end over this 
reel. What happens when the loose end of the thread 
is held and pulled down? The weight tied at the other 
end gets lifted up. 
Such a device with a grooved wheel and thread  
designed to lift weights is called a pulley.
1. All of you must have enjoyed sitting on a giant 
wheel. What makes the giant wheel go round ? 
The giant wheel is fitted to a rod at its centre. This 
rod is called an ‘axle’. When the axle starts rotating 
with the help of electricity, the wheel fitted to it also 
starts rotating. This combination of an axle and a wheel 
is a simple machine. We see innumerable examples of 
its use.
2. When the pedal of a bicycle is rotated, the wheel 
starts rotating. How does this happen ?
A wheel and axle
A pulley
12.12 : A giant wheel
Can you tell ?    
How does it help to use a pulley ?
If we use a pulley, force can be applied in the downward direction for lifting the 
weight in an upward direction. This is convenient and easy. You must have seen some 
examples of pulleys in day-to-day use. Make a list of these.
Use your brain power !
Some machines we use in our  
day-to-day life are shown in the 
picture. What is the type of lever in 
each of these ?
Let’s try this.
12.11 : A pulley in everyday life