violet part) is a good source for D3 vitamin for our body. Our body produces the vitamin from the
sunlight falling on the skin. Deficiency of D
vitamin is not good for us.
Blood pressure may be reduced by
exposure to sunlight, as dilation of blood vessels may happen. Perhaps the infrared radiation present in
sunlight also helps brain function better.
doctor-expert-inventors of old times, Charaka, Sushruta and Vaghbhata wrote in Ayurveda about pathogens being invisible and causing diseases and
infections. Girolamo Fracastroro in 16the century and Francesco Redi worked on the subject.
Discovery of micro organisms and pathogens by pioneer of microbiology –
in the 17th century – by Anton Van Leewenhoek is probably
first. Nicolas Andry and Rchard
Bradley proposed theories on the pathogens. Agostino Bassi proved by experiments that pathogens cause
We require two types of
nutrients. Macro nutrients are needed in
big quantities and micro nutrients in small amounts. We need to eat sufficient amount of fibrous
foods (micro nutrients) for good digestion purpose.
We need to drink water – about 2 litres each day. We
need small amounts of salt too, but large amounts are dangerous.
Macro nutrients consist of
carbohydrates, proteins, vitamins and fats. Vitamins are needed for the organs to function
well and increase our body defense. Fats and carbohydrates give us immediate
energy through metabolsm. Proteins help us to grow.
We need to eat fruits,
vegetables, pulses, rice or wheat, milk and eggs We need to eat regularly and in sufficient
quantities, but not excess. We need to
also breathe in fresh and clean air. We
need to keep our environment clean.
Sufficient exercise is essential to
keep the body fit and healthy.
Haemoglobin is a protein in
the red blood cells in our body. It contains
iron. Colour of blood is due to
haemoglobin. It transports oxygen from the lungs to all the
cells/tissues in the body for aerobic metabolism. Haemoglobin also carries carbon dioxide from respiration
of cells back. In kidneys, haemoglobin
regulates iron metabolism activity. Haemoglobin also carries nitric oxide gas in it, which helps expansion
and contraction of the veins. Thus blood
pressure is also monitored by it.
Sufficient amount of haemoglobin in our blood is
essential. Otherwise a person may
become anaemic. New blood cells are
formed in bone marrows. Red blood cells
have a life time of 4 months.
There are various green house gases in our
atmosphere. They are carbon dioxide, water varpour, nitrous oxide, ozone,
methane etc. They absorb the radiation from the Sun and
emit it in all directions. They emit the
radiation in thermal infrared range. This
radiation is emitted towards Earth’s surface and the atmosphere near our
surface, the temperatures are increasing gradually.
This heating effect is called greenhouse effect.
Greenhouse effect is not
same was the green house used for growing plants more efficiently. Without the greenhouse effect on Earth, the
temperatures on Earth’s surface would be very low.
6. Clouds are in the troposphere
of our atmosphere, just a few km above our surface. They are mainly a group of tiny drops/droplets
or frozen ice particles of water. Often
clouds contain some particles (aerosols) of other chemicals also suspended in
air/atmosphere. When water from Earth’s surface evaporates due
to Sun’s heat, it raises higher. Damp
air is lighter than dry air. When the air in atmosphere is saturated or when
air cools down, the water vapour forms
clouds that is visible. When the droplets are big enough, then it
We say that the process of condensation of water in atmosphere is the
cause for formation of the clouds.
7. A fertile land / soil
consists of nutrients that are required by plants to grow. A infertile soil does not contain any useful
nutrition for plants. Hence fertile soil
is needed. Fertile soil contains potassium, phosphorous, nitrogen etc. Many minerals (small but necessary
quantities) are also present like copper, iron, cobalt, boron, chlorine,
magnesium, manganese, sulphur, zinc etc. Often we use fertilizers as the soil does not contain minerals
and nutrients in sufficient quantities.
There are many
microorganisms in fertile soil that help the plants to grow.
Often soil needs to be a little acidic or a little alkaline.8.
Pollution is contamination – mixing of impurities – chemically or
physically in to substances, causing negative and undesired consequences. The impurities are called pollutants. We have water (bodies) pollution, energy pollution, sound
pollution, air pollution etc.
We control the emissions into air. We need to control chemical
effluents (from factories) into air, water bodies, and soil.
We must recycle, reuse and
reduce in a biodegradable
way. Sound pollution (noise) can be
controlled. Vehicular emissions is controlled by stricter regulations.Good, practical and economic non-polluting methods for manufacturing need to be invented.