Blog 11: Magnetics, Ferrofluid

Ferrofluid is a liquid that contains iron, which means it can be affected by a magnet. In this video, these people use a magnet to play with the ferrofluid. notice that the spikes are radiating outward from the magnet; they are following the electric field lines around that magnet. Also, the spikes are only around the magnet because they are being affected by the magnet's electric field. Doesn't it look so cool?

But, there is much more science going on here than I can tell you at the moment. This video explains a more in depth reason for why ferrofluid does what it does.

Blog 10: Heat, Playing Tennis on the Hottest Day EVER

This weekend, me and some friends decided to meet up for some friendly doubles. Too bad we planned it on the day with what had to have been the hottest afternoon in the whole week. But, that turned out to be a good way to experience physics anyway, so the heat wasn't all that bad.

In this first picture, you see one of the legs of a regular tennis bench touching the tennis court. When everyone was tired from tennis and ready to take a break, we decided to sit on the benches instead of the ground. But why? Well, besides being a normal human convention, sitting on the bench was cooler than sitting on the ground. This is because the specific heat of the bench must have been greater than that of the ground, meaning it heat up relatively slower than the ground. The leg and the ground though, are touching. So actually, if no more heat were added to the system, the two would reach an equilibrium temperature by the zeroth law of thermodynamics and conduction.

Now let's zoom out  because obviously that first picture wasn't physics-y enough anyway. Now we can see Max touching the bench! Because of the zeroth law and conduction, heat diffuses between himself and the bench, allowing the two to come close to an equilibrium. This is why eventually, the bench won't feel warm anymore. Also, as you might be wondering, where is all this heat coming from anyway?? The answer is the sun of course; heat travels by radiation from the sun to earth. And while we're on the subject of ways to transfer heat, convection was also present in the air around the hot tennis court, sadly adding to our discomfort.