Blog 9: Dryer Sheets

In class we were talked about how sometimes when your clothes come out of the dryer they cling to you or each other because of static electricity.  Static electricity is more common in dry places with low humidity like dyers becase objects can keep their charge imbalaces longer.  When we were talking about this, I wondered why my clothes are never usually never clingy and I figured it was just because Hawaii is pretty humid but this weekend I found out that my mom uses dryer sheets when she does laundry. I guess the fact that I didnt know what dryer sheets even were before this shows how rarely I do my own laundry... Usually in dryers, clothes become charged because the different materials of the the different clothes have different affinities for electron so they transfer electrons as the rub against each other (charging by friction).  Dryer sheets are useful because not only are they the explanation for why my clothes are always magically soft and smell delightful after my mom washes them, they also reduce static cling by lubricating all the clothes with the same chemical so that all the clothes have the same affinity for electrons and none of them will become charged.  They will be even more useful next in college on the mainland because of the drier environment. Yay for dryer sheets! For all the people in my class who didnt know what dryer sheets were, GET SOME AND USE THEM, they make your clothes so soft its so wonderful!!!!! I know it looks a little weird and gross in the picture, but seriously they are great.

Blog 8: Center of Mass & Torque

This is a picture I took this summer of a catherdral in Spain which is still under construction even though it's super old.  The carthedral is pretty amazing but it was pretty irritating that there was so much construction equiptment and noise from power tools etc.  Beyond that I never really gave much thought to all the cranes around the cathedral.  At first glace, it seems amazing that the cranes can balance even though they have one really long end sticking out that is obviously not over the support base.  If the horizontal part of the crane was uniform then the weight of it would create a torque(force x lever arm) in the middle of its arm, and it would tip over because of unblanced torques.  However, when you look at this picture, you can see that the short end of the crane's arm has a lot of weight on the end of it.  This makes it so the center of mass is closer to the right side and the center of mass is therefore over the support base.  Now the crane wont tip over!