CLASS 10D SCIENCE

Our Environment Important Instructions: (i) Keep your text book open for reference. (ii) Home Assignment need to be done in your Biology note book. (iii) Complete your index, put chapter name and date when you start (iv) All the intext exercises as well as exercise given at the end of the chapter have to be done. Learning outcomes: define ecosystem and study its components classify ecosystem into various types on the basis of their nature and size develop the definition of a food chain Introduction Environment Includes all living and nonliving things. There need not be any necessary interaction between them.(unlike an ecosystem) Eco system An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. Components of an ecosystem   The biotic components are all living organisms.  The non-biotic components are physical factors like air, water, soil, win

SOURCES OF ENERGY Lesson 4    Hello everyone! I hope you are keeping well and taking good care of yourself! Learning outcomes : explore alternate sources of energy giving prime importance to environmental  conse q uences All  energy sources  have some  impact  on our  environment .  Fossil fuels—coal, oil, and natural gas—do substantially more harm than renewable  energy sources  by most measures, including air and water pollution, damage to public health, wildlife and habitat loss, water use, land use, and global warming emissions. No source of energy can be called pollution-free, because, the use of any source of energy disturbs the environment in one way or the other.  A source of energy like a solar cell is pollution free in actual operation but the assembly of the device might have caused some damage to the environment. So, in absolute sense,  no source of energy can be called pollution free. NCERT Page 253   Q. Hydrogen

SOURCES OF ENERGY  Lesson 3   Good Morning All ! Learning outcomes : develop the concept of non conventional energy sources energy from the sea , geo thermal energy , nuclear energy  list the significance of the above resources. Energy From the Sea The seas and oceans and other water bodies are a source of kinetic and potential energy due to the immense volume of water and the motion of waves. Tidal energy Tides are variations in the level of water due to the gravitational pull of the moon. The phenomenon of rise and fall of water level or high and low tide gives tidal energy. Tidal energy is obtained by constructing dams near the narrow openings of the sea. When the tide sets in, it moves the turbine which directly produces electricity. It is limited to places near the sea. Wave energy Waves possess a lot of kinetic energy that can be harnessed to produce electricity. Waves are produced by strong winds blowing over the sea. Limited to places

SOURCES OF ENERGY   LESSON 2 Welcome students! Learning outcomes :  At the end of the topic, learners will be able to 1. analyse the structure , function and uses of a biogas plant. 2. appreciate the technology of drawing best out of waste 3. interpret the advantages and disadvantages of using wind energy , solar energy as sources of energy. Instructions: Topic marked in red need to be copied in Physics note book. Biomass Biomass is the source of energy derived from living things (organic matter).  biowaste such as cow dung  When wood is burnt in a limited supply of oxygen and water until volatile materials are removed, the residue left behind is charcoal.  Charcoal has good heat generating efficiency. It also burns without flames. Bio-gas plant Cow dung, sewage waste, plant matter are decomposed in absence of oxygen to produce biogas.  A biogas plant is a dome-like structure built with bricks where cow dung and other biowaste are mixed with