Entry Twenty: What's That in your iPod?

This weekend, I listened a lot to my iPod, which happens to be powered by a lithium-ion battery. This is a battery that uses the chemical reactions of lithium and carbon to produce energy, and it can store about 150 Wh of energy. The iPod is powered by a pack of these batteries, so it can play for several hours before it needs a recharge. This is great for listening to the Power Rangers Theme song over and over again, and also great for listening to anything else. The thing is, these batteries have the problem of occasionally bursting into flame, which is scary.


Lithium-Ion Battery . . .

Entry Nineteen: Quis custodiet ipsos custodes?

I saw the Watchmen this weekend. It was a brilliant book, and the movie was pretty good, considering that it had to condense the complex storyline into a two hour and forty-five minute (long) movie. There were many physics concepts that were involved, such as teleportation and time travel, but I think we learn that in the fourth quarter. For now, I shall discus the electricity involved in the movie. Well, the story takes place in an alternate universe where electric cars are the norm. I assume that the electric cars use the same properties of electric flow that we do here in the regular universe. That being said, they probably use batteries, which are cells that have potential energy differences between the positive and negative terminals. When a current goes through the circuit, the potential energy is raised by whatever the voltage of the battery is. A car battery is about 12 volts, so each coulomb that flows through the circuit has its energy raised by 12 Joules. I hope I got that right. In any case, go see the Watchmen, but please read the book first.

Car Battery

The Watchmen. Cooler than a battery.