#Class 5 SST Chapter 13 Important Notes. #Class 5 SST Chapter 13 The Age of Machines
What is the age of machine?
The time in which we are living is called the age of machines.
A machine is a tool that makes our life easier. Our life has become totally dependent on the machines and life without the machines is very difficult.
Early Stone Tools
Millions of years ago, humans did not have these machines and they were dependent on simple stone tools made by themselves as per their skills. These stone tools were used for hunting.
It took thousands of years for developing the tools made of metals. But last few hundreds years have seen rapid growth in technology and there have been so many machines invented during this time.
Discovery of Metals
- Copper was the first metal to be discovered about 8000 years ago in Asia.
- Bronze was the next metal to be used.
- It was made by mixing copper and tin.
- It was harder than copper. Bronze was first used about 6000 years ago.
- Iron was the next to be discovered.
- Iron was harder than bronze.
- Iron tools were used to cut down the tree and clearing forests for agriculture.
- It was easier to hunt the animals with the iron tools.
- Iron tools helped the humans grow faster.
Wheels, Carts and Boats
- Wheel was invented about 5500 years ago.
- Carts with wheels fitted were started to be used about 5000 years ago.
- Initial pulled by the humans but later animals were used to pull these carts.
- Humans started using rafts (early boats) about 10000 years ago.
- Later humans used the force of the wind and made sailboats.
- Water mills were also among the important machines that were used in ancient times.
The Steam Engine and The Industrial Revolution
Till seventeenth century, humans used the power of their own muscle power, animals, force of the wind and force of the flowing water.
- Goods could be produced in large quantities in the industries.
- The goods became cheaper and better in quality.
- People started using more goods and demand of the goods increased.
- This increased demand led to the factory system where goods could be manufactured at large scale.
- More people were employed in the factories and people move from villages to the cities.
- Cities grew bigger in size.
- Many changes in the economy, society and culture started to happen.
This significant change from hand made goods to machine made goods began in Britain in 18th century. This change is known as the industrial revolution.
Conventional Sources of Energy
- First fuel to be used in steam engines to produce steam.
- Coal is obtained from the mines.
- Coal is still an important source of energy for us and used to produced to generate electricity.
- Coal is formed from the dead trees millions years ago.
- Coal is limited and it would last for only about 250 years.
- Another source of energy found deep inside the Earth.
- Petrol, kerosene, diesel etc. are taken out of petroleum.
- Engines running on petrol and diesels are better than the steam engines.
- So the petrol and diesel engines have replaced the steam engines in the machines and automobiles.
- Petroleum is also limited and will exhaust in about 100 years.
- Alessandro Volta was the first person the make a battery that could produce electric current.
- With the time, generators were invented which could produce electricity.
- Petrol, diesel, coal, natural gas etc. are used to run the generators and produce the electricity.
- Hydroelectricity is produced by constructing the dams on the flowing rivers.
Alternative Sources of Energy
Conventional fuels are limited and they also cause the pollution. Therefore development of the other sources of energy is very important.
Atomic energy, Solar energy, Wind energy, hydroelectricity etc. are the alternative sources that can be used more and more in the future.
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