Monday, June 30, 2014
Tuesday, June 17, 2014
Sunday, June 15, 2014
The pollution is very dangerous , and you should know that there are different kinds of pollution as the air pollution , the water pollution and the soil pollution , The pollution is any change in the environment that disturbs its natural balance .
Saturday, June 14, 2014
We have known that the Sun is the main source of energy , and it is very important in our life .
But you should know that there are resources of energy which are the renewable sources of energy and the non renewable sources of energy .
Friday, June 13, 2014
Wednesday, June 11, 2014
People use the levers but they do not know the type of them and how to determine the type of any lever .
Do you know that the levers are classified according to the location of the effort force , the resistance force and the fulcrum ?
Sunday, June 8, 2014
|The levers are very important in our life to perform tasks more easily .|