If you’ve been following Pop Physics (especially if you’ve stuck through the overlong and unannounced hiatus that started with the new school year) and are still in school, there’s an excellent chance that you’ll end up working for one of these projects someday! The Experiments Most Likely to Shake Up the Future of Physics Here’s … Read more
Today, I’m going to do one better: an indiegogo campaign called “Home Quantum Energy Generator” has raised $16,902 (far surpassing its oddly specific goal of $7,610) to build a protoype Free Energy device. This thing features several of the hallmarks of modern physics quackery:
An inventor who is specifically not a trained physicist, but a “career Electronics Engineer”
When you start to learn about Special (or General) Relativity, one of the first question you’re almost guaranteed to ask is, “Why do things get so weird when you approach the speed of light?” My favourite answer to this question is to say that if we lived our lives at relativistic speeds, our current low-speed, “normal” world would seem just as bizarre.
Unfortunately, most of us don’t have access to the kinds of energies required to experience relativistic effects first-hand. Luckily, modern technology has provided us two glimpses into the kinds of mind-bending phenomena described by Albert Einstein.
First off, there’s the 3D, MIT-created, graphically beautiful game called A Slower Speed of Light. This first-person non-shooter, developed at MIT’s Game Lab, is free to download, so go try it out now. The goal of the game is to navigate a 3D world and collect spheres, which incrementally reduce the speed of ligh, amplifying effects like time dilation, Lorentz contraction, and the Doppler shift. Or in lay terms, stuff just keeps getting crazier.
Well, it’s now just over a year since Curiosity landed on Mars. What better way to celebrate than a stop-motion video with a hard-rockin’ soundtrack? Here you can see this excellent robot wandering around the dunes, grabbing soil samples, and generally having a marvellous time, all through the fish-eye lens mounted on the front of … Read more
Why can’t we build a machine with 100% efficiency?
After a shamefully long delay, let’s take a look at the consequences of entropy. In the previous section, I described entropy as a measure of the statistical probability of a state.
One of the most significant results of this kind of thinking is that, because high-entropy states are more likely than low-entropy ones, the total entropy of the universe will always tend to increase over time. We have to say “tend to” here because things like all of the air particles in a room jumping to one side can, technically, happen. But if every process obeys this statistical reasoning, then instances of spontaneous entropy decrease are so unlikely that they are essentially impossible, so the total entropy of everything will always be naturally increasing.
Here’s where we can connect things back to energy. First of all, if you want to reduce the amount of entropy in a certain area – like arranging the bricks into a wall – you have to expend some energy.
Yes, it turns out the two things in the title of this post have comparable sizes. Who knew? A neutron star is a very old star that has burned off most of its energy and then collapsed into itself. As a younger star (such as our sun) undergoes the nuclear fission reactions that make it … Read more
We’re halfway through our discussion of entropy, which is a perfect place to take a quick break for a video. It may not be very exciting, and it may not be very clearly explained, but it’s related to our current topic and may at least ignite your curiosity a bit. We’ve all thought about time, … Read more
In order to gain a full appreciation for energy, the last idea you’ll need to understand is something called entropy. It’s kind of a tough one, but I guarantee it’ll be worth it if you persevere to the end of this chapter!
The reason I’ve saved it for last is that many people find entropy quite difficult to understand. There are two reasons for this: one is that it’s another purely abstract concept; the other is that there are about twenty different ways to define entropy, and they all seem very different from each other.
Luckily for us, however, there is one easy way to understand entropy that we can explain with a simple example.
Take a large cardboard box, a can of red paint, and a can of blue paint.[1. Note: the actual colours are not important. Let your aesthetic sense be your guide.] We’re going to paint the inside of the box in these two colours: red for the left-hand side, and blue for the right.
Once the paint has dried, grab 8 ping pong balls again[2. This is no coincidence. I will not hide the fact that I like ping pong balls.] and put them into the box.
This lovely 3D panorama, which was made by photographer Andrew Bodrov, is a stitched-together collection of photos taken by the Mars Curiosity rover. It’s a desolate image, but still immersive and a bit magical. From a related Wired article: “The best way to enjoy it is to go into fullscreen mode and slowly soak up … Read more
What is the difference between heat and temperature?
What happens when water freezes or boils?
It may seem out of place to start talking about heat and temperature in the middle of a chapter about energy, but in fact, there are many connections between these ideas. And in order to understand the ways in which we can and can’t use energy, we have to know something about heat.
The first thing science teachers do when teaching this topic to young people is try desperately to communicate the idea that heat and temperature are, in fact, two very different things. I never really understood why this seemed so important to them, but nevertheless, they’re right.
Heat, in physics, is a quantity of energy that is transferred from one object to another. When you hold your hand over a fire and your hands get hotter, heat has been transferred from the air into your skin.
Temperature, on the other hand, is a measurable property of any object. Specifically, it is a measure of how quickly the particles in that object are vibrating.
You see, it’s fine to picture solid matter as being made up of all of these atoms and molecules and whatnot, but these particles do not sit around waiting for stuff to happen. Even in a seemingly still, solid object, the particles that make up matter are constantly vibrating and bumping into each other.[1. This is called Brownian motion, named after the Scottish botanist Robert Brown, who noticed this behaviour when looking through a microscope at grains of pollen.] And when heat is transferred into an object, its particles vibrate more than before.