density

Dot Physics

Category archives for density

Pressure demo: suction

How does a suction cup work? It is all about the atmosphere. Here is a demo. Take some type of “suction cup” device. In this case, I used a toy dart. Stick it to something smooth and lift it up. Like this: What lifts up the metal block? The atmosphere. Diagram time: But this isn’t…

Debris field for a broken meteor

I happened to catch two parts of two different episodes of Meteorite Men – a show about two guys that look for meteorites. In both of the snippets I saw, they were talking about a debris field for a meteor that breaks up. In these fields, the larger chunks of the meteorite are further down…

Flying R2-D2, you are doing it wrong

You know I can’t help but like Star Wars. Even with the new stuff, I watch it. Recently, I was watching the Clone Wars cartoon and noticed something odd about the way R2-D2 flies. I know what you are saying….”the odd thing is that he flies at all. Why didn’t he fly in episodes 4-6?”…

Battery to power a house for a week

I saw this post about Panasonic’s home battery. The claim is that this will lead a battery that can power a house for a week. I wonder if I can estimate how big this battery would be. First – to estimate the energy a house consumes. My first approximation is that you could probably run…

On a previous episode of The MythBusters, Adam and Jamie made a lead balloon float. I was impressed. Anyway, I decided to give a more detailed explanation on how this happens. Using the thickness of foil they had, what is the smallest balloon that would float? If the one they created were filled all the…

RP 4: More on the movie Up! (or Upper)

So, analysis of the movie Up is pretty popular in the blogosphere. Figure I might as well surf the popularity wave. So, I have a couple more questions. The most important thing to estimate is the mass of the house. I am going to completely ignore the buoyancy of the house. I figure this will…

One of my students showed me this game, Fantastic Contraption. The basic idea is to use a couple of different “machine” parts to build something that will move an object into a target area. Not a bad game. But what do I do when I look at a game? I think – hey! I wonder…

There is this show “Weapon Masters” – I think it comes on the discovery channel. It is not a bad show. The basic idea is that they have this history guy talk about the historical aspect of some type of weapon and this other guy tries to make an improved version. Last night the goal…

MythBusters – a tree is 90% air

Dear Mythbusters. I hope you know that I think you are awesome. I know you are not scientists, but rather master robot builders. I respect that. I envy your robot-building abilities. Please forgive me for pointing this out – but even if a tree is 90% air, that does not mean a ball has a…

On a previous episode of The MythBusters, Adam and Jamie made a lead balloon float. I was impressed. Anyway, I decided to give a more detailed explanation on how this happens. Using the thickness of foil they had, what is the smallest balloon that would float? If the one they created were filled all the…