Author: haroonkhan

Let’s return now to the notion that we can predict the position of the moon, and thus the status of the tides, at any time in the future. Surely this means you’ll be able to predict whether you could go crabbing at noon on your thousandth birthday, right? In theory, the answer is yes. In…

Newton’s work touched not only on math and physics, it also had philosophical ramifications. For any system of bodies interacting via the force of gravity, he showed that the present position and velocity (the present state) of each body actually determines what their positions and velocities will be at all times in the future (their future…

One reason Newton’s discoveries were so remarkable is that they explained the underlying basis for many phenomena that hadn’t previously been understood. Before Newton, scientists could explain how the planets moved about the sun, but they could not explain “why.” Newton’s gravity provided the answer. Or did it? We can say Earth’s gravity holds the…

After discovering his three laws of motion, Newton could have easily enjoyed a quiet, early retirement in the English countryside. Fortunately for us, he decided to make yet another groundbreaking contribution to physics. (In fact, he made several more revolutionary contributions to math and physics, which you can read about in other Idiot’s Guides.) One day,…

We will talk a lot about forces. By this we’re not referring to any special powers from a time long ago or a galaxy far, far away. Instead, we are referring to the ways that physical objects interact with each other. Even if you are quietly seated in your armchair, you are influenced by a…

We will explore the concept of force and the basic laws of motion. The laws governing every branch of physics, including classical and quantum physics, ultimately boil down to forces that act on various objects from the very, very big to the very, very small. We will also explore gravity, the attractive force between all…

We described the process of measurement and discussed how important this was to developing and refining the laws of physics. In the macroscopic world the process of measurement can usually be done independently of, and without having any influence on, the system you are trying to observe. If you want to know the length of…

We regularly use the concept of uncertainty whenever we don’t have definite knowledge of something that might happen. If the weather lady says there is a 60 percent chance of rain at a certain location tomorrow, she can’t predict that it will definitely rain. She can only ascertain that rain is more likely than not…

The second major difference between quantum physics is the uncomfortable notion that in the microscopic world, you cannot always rely on ordinary logic. Physicists find this especially troubling since logic plays such an important role in science as a whole. When inconsistencies arise, it begins to cast doubt on the notion that a coherent framework…

First, quantum physics tells us that as you move to smaller and smaller scales, some important physical quantities become “pixelated.” Things that appear to be continuous (smooth and gradual) at the macroscopic scale are in fact discrete and chunky at the microscopic scale. In other words, they are limited to distinct, well-separated values. For example,…