(a) What is meant by 'heart beat'? What is the usual heart beat rate at rest?
(b) What change occurs in heart beats if a person runs for a while? Why?
Answers
Answer:
a] The systole (contraction of heart) and the diastole (relaxation of heart) makes the heart beat.the contraction of heart and relaxation of heart occurs because of the pumping of blood all over the body and to lungs. the left side of the heart pump pure blood all over to the body. the right side of the heart pump impure blood to the lungs for oxygenation. a person over 10 years would have the heartbeat of 60 to 100 per minute.
b] When a person runs for a while his heartbeat will be increased as the heart pumps more pure blood all over the body and impure blood to lungs.
this is because our body requires more oxygenatoed blod while we are running or doing exercise.
Answer:
Lightning
Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. ... Lightning causes thunder! Energy from a lightning channel heats the air briefly to around 50,000 degrees Fahrenheit, much hotter than the surface of the sun.
Precautions
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Avoid water during a thunderstorm. Lightning can travel through plumbing. Avoid electronic equipment of all types. Lightning can travel through electrical systems and radio and television reception systems.
✯Stay away from wire fences, clotheslines, metal pipes, rails and other metallic paths which could carry lightning to you from some distance away. Avoid standing in small isolated sheds or other small structures in open areas. In a forest, seek shelter in a low area under a thick growth of small trees.