حل تمرين 50


ladies and genteleman Ihave a dream that all children of my age will be able to vote and have a part time job.Ihave a dream that soon the adults will be able to understand that age is not reflection of intellegence age is not a reflection of maturity our grand parents were able to do many things successfully voting getting married working driving and even making war att a quite early age.


write it right page 83

Like air, water is found almost everywhere. It is familiar to us in different
forms, as drinking water, water vapour, ice and snow.

Water has some surprising qualities. For example, most liquids freeze and
become denser, but water becomes lighter. When you fill a pan of water, with
ice cubes, you note that unmelted particles remain on the surface. The reason
is that frozen water is lighter than water in liquid form. When water expands,
it becomes ice and it exerts pressure. If you fill a glass bottle and put it in the
freezer, the bottle breaks. As the frozen water expands, it exerts pressure on the
glass bottle.

Water molecules have a strong attraction to each other. The force of attraction
is called cohesion. If you moisten two pocket mirrors and stick them together,
you will not be able to pull them apart. The water molecules on the surface of
the pocket mirrors attract each other. But it is not difficult at all to separate dry
mirrors because ...