What is the elastic clause and its significance?

The elastic clause or necessary and proper clause is a clause located within the Constitution. The clause is located in Section 8 Clause 18 of the Constitution. The necessary and proper or elastic clause is important because it grants Congress sweeping powers to make any law that is "necessary and proper" to enforce the constitution. This means that anything not specifically included in the Constitution can be made into a law if the Congress believes that it is necessary to uphold some element of the Constitution. 

The congress has the right and the ability to stretch laws based on the validity in time. For example, when the constitution was written, congress had the right to establish an army and a navy. Well in 1947 that all changed because the air force was established. We all know that besides the french and their hot air balloons there were no air forces back in the late 1700's. However, under the elastic clause it is also implied that congress has the right to establish and grow an air force.