1. How is salt prepared from seawater?
4. What is a thresher and why it is considered an efficient machine?
5. How will you separate the components of a mixture of salt sand and iron scraps? explain?
2. Explain the methods of sedimentation and decantation by using clay.
3. Explain the process of winnowing in detail.
Answers
Answer:
1.Sea salt is salt that is produced by the evaporation of seawater. It is used as a seasoning in foods, cooking, cosmetics and for preserving food. It is also called bay salt, solar salt, or salt. Like mined rock salt, production of sea salt has been dated to prehistoric times.
4.A threshing machine or a thresher is a piece of farm equipment that threshes grain, that is, it removes the seeds from the stalks and husks. It does so by beating the plant to make the seeds fall out. ... Mechanization of this process removed a substantial amount of drudgery from farm labour.
5.Iron is magnetic and the other two not, which means a magnet could be used to attract the iron filings out of the mixture, leaving the salt and sand. Salt is water soluble, while sand is not. This means the two can be mixed in water and stirred. The salt will dissolve and the sand will not.
2.Sedimentation and decantation methodsare used for the separation of insoluble substances which are heavier than liquid. In the sedimentation process, heavier components of the mixture settle on the bottom, due to gravity. Decantation is followed by sedimentation.
3.Winnowing is a farming method developed by ancient people for separating grain from chaff. ... In its simplest form it involves throwing the mixture into the air so that the wind blows away the lighter chaff. The heavier grains fall back down for recovery. This method is called "wind-grading".
1) Sea salt is salt that is produced by the evaporation of seawater. It is used as a seasoning in foods, cooking, cosmetics and for preserving food. It is also called bay salt, solar salt, or salt. Like mined rock salt, production of sea salt has been dated to prehistoric times.
4) A threshing machine or a thresher is a piece of farm equipment that threshes grain, that is, it removes the seeds from the stalks and husks. It does so by beating the plant to make the seeds fall out. Mechanization of this process removed a substantial amount of drudgery from farm labour.
5) Iron is magnetic and the other two not, which means a magnet could be used to attract the iron filings out of the mixture, leaving the salt and sand. Salt is water soluble, while sand is not. This means the two can be mixed in water and stirred. The salt will dissolve and the sand will not.
2) Sedimentation and decantation methodsare used for the separation of insoluble substances which are heavier than liquid. In the sedimentation process, heavier components of the mixture settle on the bottom, due to gravity. Decantation is followed by sedimentation. Hope this helps you.
3) Winnowing is a farming method developed by ancient people for separating grain from chaff. In its simplest form it involves throwing the mixture into the air so that the wind blows away the lighter chaff. The heavier grains fall back down for recovery. This method is called "wind-grading".