We must know the importance of echo in our life, There are many applications of echo in different fields whether scientific, technical or medical such as determination of the speed of sound through the...
The electric conductivity The substances can be classified according to the electric conductivity into good conductors of electricity and bad conductors of electricity, The electrical conductivity is the ability of a material to carry...
The fertilization process in the human The fertilization is the fusion of the nucleus of male gamete (the sperm) with the nucleus of the female gamete (the ovum) to form the zygote (the fertilized...
Hardness of materials Some solid substances are soft at room temperature such as the rubber, and some solid substances need heat to become soft and easy to be shaped such as the metals, and...
