Find out about the traditional systems of water harvesting/management in your region.
There are many traditional methods of water harvesting or management like khadin system, ponds, tals, canals, kohli tanks, rain water harvesting, saza kuva, and wells have been dug for the drinking water. Many water reservoirs are made by the government for the drinking water for humans as well as animals.
Water has been harvested in India since antiquity for the water management and for saving the water in drought conditions. By harvesting the rain drops with the direct connection from the rooftop where water is collected to the tanks where water is stored built in the courtyard, this is rain water harvesting system; khadin is also known as dhora and used to harvest surface runoff water for agriculture; ponds are the large water harvesting system for the groundwater recharge, infiltration etc; kohli tanks are the main water harvesting system or ancient harvesting system, it is cylindrical shaped formed underground and when rain comes it fills with water and keep it cool or fresh rainwater in it; kuva, wells, canals have been made by the artificial methods for the water harvesting or management.
As in the chapter showing the khadin, tanks and nadis as the traditional system of rain water management system in Rajasthan, also known as dhor; Bandharas and tals in Maharashtra; bundhis in Madhya Pradesh and Uttar Pradesh; Surangams in Kerala; and Kattas in Karnataka are used as ancient water harvesting systems. In largely level terrain, the water harvesting system is composed of earthen embankment or low, check dams are built across seasonally flooded gullies. Monsoon rain filled behind the structures only the large structure will hold the water for the long- range. The main purpose of the water management is not only to hold the water of the surface level but also holds the ground water level as well. Groundwater do not evaporate and spreads to fill the wells and provides moisture the earth and the soil respectively.
Suggest some approaches towards the conservation of forests.
We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?
List five things you have done over the last one week to —
(a) conserve our natural resources.
(b) increase the pressure on our natural resources.
Find out the source of water in your region/locality. Is water from this source available to all people living in that area?
How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?
Why should we conserve forests and wildlife?
Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.
What changes can you make in your habits to become more environment-friendly?
What can you as an individual do to reduce your consumption of the various natural resources?
Why do you think that there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?
Write an equation to show the reaction between Plaster of Paris and water.
What are oxidising agents?
Which element has
(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.
Write the balanced equation for the following chemical reactions.
1. Hydrogen + Chlorine → Hydrogen chloride
2. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3. Sodium + Water → Sodium hydroxide + Hydrogen
Write the balanced chemical equation for the following and identify the type of reaction in each case.
(a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)
(b) Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)
(c) Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)
(d) Magnesium(s) + Hydrochloric acid(aq) → Magnesium chloride(aq) + Hydrogen(g
What is a balanced chemical equation? Why should chemical equations be balanced?
An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image, its nature and size.
When does an electric short circuit occur?