Human Heart

Did you give your friends valentines and little heart-shaped candies on Valentine's Day? Your have you ever blessed any one form the bottom of your heart or may be cursed someone from the bottom of your heart? We have been hearing that many feelings come from the heart. This simply means that Heart is the most important part in a Human body.

The human heart is a pear-shaped structure about the size of a fist. The heart is an amazing organ. It is responsible for supplying the body with oxygenated blood. Each time the heart beats, it exerts a pressure on the veins and arteries called Blood Pressure. The heart is one of the most important organs in the entire human body. It is really nothing more than a pump, composed of muscle which pumps blood throughout the body, beating approximately 72 times per minute of our lives.
How does the heart beat?

Before each heart beat, the heart fills with blood. Then its muscle contracts to squirt the blood along. When the heart contracts, it squeezes — try squeezing your hand into a fist. That's sort of like what the heart does so it can squirt out the blood. The Heart does this all day and all night, all the time.

What is Physics?

The nature around us is colourful and diverse. It contains phenomena of large varieties. The winds, the sands, the waters, the planets, the rainbow, heating of objects on rubbing, the function of human body, the energy coming from the sun and the nucleus...... there are large number of objects and events taking place around us.

Physics is the study of nature and its laws. We expect that all these different events in nature take place according to some basic laws and revealing these laws of nature from the observed events is Physics. Physics is concerned with the basic rules which are applicable to all domains of life. Thats is why physics is known as real since it is the study of nature. No one has been given the authority to frame the rules of physics. We only discover the rules that are operating in nature. Some of the great physicists are Aryabhat, Newton, Einstein and Feynman.

Spherical Mirrors

A spherical mirror is a mirror which has the shape of a piece cut out of a spherical surface. A spherical mirror is simply a piece cut out of a reflective sphere. Its center of curvature, C, is the center of the sphere it was cut from. R, the mirror's radius of curvature is the radius of the sphere. The focal point F (the point where parallel rays are focused) is located half the distance from the mirror to the center of curvature.

Types of Spherical Mirrors:

• Concave Mirrors
• Convex Mirrors

Concave Mirror: If the mirror's inside surface is reflective, the mirror is concave.Concave mirrors can form either real or virtual images, depending on where the object is. The Image below is an example of Concave Mirror.



Convex Mirror: If the mirror's outside surface is reflective, it's a convex mirror. A convex mirror can only form virtual images. A real image is an image that the light rays from the object actually pass through; a virtual image is formed because the light rays can be extended back to meet at the image position, but they don't actually go through the image position.The Image below is an example of Convex Mirror

Minerals

Minerals are inorganic nutrients. They include both metallic and non-metallic elements, which are taken by the body in the form of salts. There are 24 elements that are used in our body. They have various functions such as formation of tissues such as the bone, conduction of nerve impulses, formation of RBCs, etc. There are eight major elements required by man and the others are needed in traces. The major elements are sodium, chlorine, potassium, calcium, phosphorus, sulphur and magnesium. Some of the trace elements or microelements are fluorine, zinc, copper, iodine, iron, manganese, chromium, cobalt, etc. However, they are all important for the well-being of the human body. All the minerals are basically obtained from the plants as they absorb these minerals from the soil.