Newton and the Science of Motion

Biography of Isaac Newton

Newton's laws of motion help to show the difference between science and technology. Newton observed many different things concerning motion, and then described motion in three laws.

First Law: every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. This is also known as the law of inertia.
Second Law: the force on an object is equal to its mass times its acceleration. F = ma The unit of force is the Newton and is equal to the force required to change the velocity of a 1 kg mass by 1 metre per second in one second (1 kg·m/s² = 1 N).
Third Law: for every action there is an equal and opposite reaction.

If we consider the three laws together, we can reach these conclusions:

An object will keep moving at the same velocity unless we apply a force to it. In our normal experience this seems to be false, but this is because friction is a force.
If we do apply a force, then the object will accelerate. Acceleration and force are vector properties; that is, they have both a size and a direction. Acceleration in the reverse direction – deceleration – is still an acceleration. Friction is a force that decelerates objects.
A force will always have an equal and opposite reaction force.

Newton was trying to figure out why the world works the way it does. He didn't really have any practical applications in mind.

Without any knowledge of these scientific principles, the Chinese developed rocketry. Sometimes, technology doesn't always develop directly from science. Most often, however, technology does depend on science and develops as a result of our knowledge of it. If we didn't have Newton's laws of motion, we wouldn't have been able to develop the incredibly powerful rockets we have today. And we certainly wouldn't be able to predict where they were going to land!

Technology and science have become so interconnected that today it is often difficult to keep them separate. Remember that science is a way to get knowledge. Science is not the knowledge itself, nor is science the products we get from using that knowledge. The science Newton did was in observing the motion of objects in nature, and trying to describe and explain that behavior in terms of experimentally verified observations.