Theories and Laws_Lower_Level_02
Laws
Laws are like theories. But they have slight differences. Laws and theories both explain things using evidence. A law describes what happens. A theory describes how or why something happens. For example– If you drop something, what happens? We expect the object to fall to the ground. We know that objects fall to the ground from experience. Now– if you look into space, what do you see? Objects being attracted to one another. Examples of gravity are all around us. The law of gravity was developed to describe the attraction between two objects.
The law of gravity states that all matter in the universe (that scientists know of) has a force of attraction. This force is called gravity. One gravity experiment took place on the Moon. On the Moon, a feather and hammer were dropped to test gravity. There was no air to resist their fall. So, they both hit the ground at the same time.
The law of gravity has served humanity well for centuries. But could it change? What if we did experiments in a different galaxy? What if when we dropped objects they didn’t fall to the ground? How would this affect the current law of gravity?
Laws can change just like theories. As society’s laws often change to suit the needs of the people. A scientific law can change to suit the needs of evidence. The law may be completely thrown out. It may even be replaced with a completely different law. This was the case when Albert Einstein’s work challenged the work of Isaac Newton.
About one hundred years ago (circa 1900) a problem arose in the field of Physics. Albert Einstein’s work in relativity (Space–Time) placed Newton’s work in jeopardy. Newton’s laws explained forces and motion. But they were not perfect. They got man to the Moon. But at speeds near the speed of light, Newton’s Laws become less exact.
Newton’s case shows how laws can change with new evidence. Scientists have explored motion and developed models to predict actions. Yet there are things they do not know.
Scientists have studied Earth’s orbit around the Sun. Scientists have studied the Moon’s orbit around Earth. These studies help us to understand the role of gravity. They also helped us create a mathematical model to predict interactions of objects. Despite the law of gravity, not all is known about gravity. The missing information explains why gravity happens. Every day we can see something falling. But why?
Why do objects fall to Earth? How does this happen? What creates this force? These questions cannot be answered with a law. A theory explains why or how. Gravity is one of the best-known scientific principles. But it lacks a theory to explain how or why it happens. In the case of gravity, we only know what happens. The law of gravity lacks a theory to explain how or why.
Conclusion
Theories and laws are both important in science. They both hold equal status. Theories do not turn into laws. Their roles are distinct. Theories explain how or why something happens. A law describes only what happens. However, theories and laws are constructed based upon evidence.
