Автор работы: Пользователь скрыл имя, 16 Мая 2013 в 05:24, контрольная работа
Being the oldest building material, wood is also known to be the only naturally growing organic material. Is wood strong? Hardly so, because wood always contains some water which decreases its strength. But after the wood is cut, the water content starts to evaporate and as the water content decreases the strength of the cut wood and its hardness start to increase. It is a well-known fact that the drier is the cut wood the greater is its strength and hardness.