density

Dot Physics

Category archives for density

Speed of a rising drop of oil

The oil spill is still in the news (sadly). One thing that keeps coming up is the speed that the oil bubbles rise to the surface. This is important in different oil-capture methods. The common statement is that smaller bubbles of oil can take quite a long time to reach the surface and larger bubbles…

What is Arnold made of?

Of course I am talking about Arnold Schwarzenegger. After looking at how many bullets he carries in Commando, I remembered this scene (also from Commando) (warning: maybe some not great language and some killing. You have been warned) If you don’t want to watch that clip, here is a shot (sorry for the quality). Clearly…

Energy in a hidden battery

Back to the discussion about hiding an electric motor in a pro racing cycle. Before, I looked at a video of Fabian Cancellara to see how his speed and acceleration compare to other bikers. The claim on the internet is that he pulls away so fast that he must have a motor hidden in his…

I am still thinking about the Red Bull Stratos Jump. Sorry, but there is just tons of great physics here. Next question – how big of a balloon would you need to get up to 120,000 feet? I am not going into the buoyancy details of Archimedes Principle – I think that was covered fairly…

Star Trek Space Jump

While I am still fresh on the Space Jump topic, let me take it to the extreme. Star Trek extreme. SPOILER ALERT But really, is this a spoiler alert if it is from the trailer of a movie that has been out forever? Of course, I talking about the latest Star Trek movie where three…

Stratos Jump for Mere Mortals

Crazy, but I was on CNN Saturday night. They contacted me at the last minute to talk about the Red Bull Stratos Jump. Here is a screen shot to show that I am not making this up (or that I have awesome photoshop skillz). Looking back, maybe I looked like an idiot. Really though, it…

Grades are in. So, let me just say a couple of trends that I saw on the physical science final exam. Gravity on the moon I asked the question: “why is the gravitational force on an astronaut less on the moon than on Earth?” The simplest answer is that the gravitational field on the moon…

Greater is Greater

I gave the following question on my last physical science (physical science for non-science majors) test: Block A has a mass of 10 kg and volume of 100 cm3. Block B has a mass of 1 kg and a volume of 1 cm3. Which block has the greater density? Which block has the greater volume?…

Oak Trees are awesome

In this part of the world, we have oak trees. Technically they are called live oaks – but I don’t get it. Of course they are alive. I was at a soccer game and this is the tree I always look at. Look how far those limbs extend horizontally. That branch is about 12 meters…

Density of Wood

This isn’t much – really it is part of another post I am working on. The point of this post is to calculate the density of this piece of wood. Really, there is a reason for this. I saw this little stick (sticklette?) and noticed that it was very cylindrically shaped. So, what if I…