Air Has Pressure!

May 14, 2007

Recently in science we have been talking about our atmosphere. We learned that our atmosphere is made up of Nitrogen, Oxygen, and Trace gases, which include water vapor (water in a gas form). 

We then learned that the water vapor can condense to form liquid water (this is what happens on the side of your McDonald’s pop).

Today we talked about the fact that air has pressure. The video below shows what happens when air pressure is not equal on the outside and inside of a can.  

Steve Spangler’s Science Website puts it like this: Here’s the real scoop on the science of the imploding can: Before heating, the can was filled with water and air. By boiling the water, it changed states from a liquid to a gas. This gas is called water vapor. The water vapor pushed the air that was originally inside the can out into the atmosphere. When the can was turned upside down and placed in the water, the water vapor condensed and turned back into the water. Water molecules in the liquid state are many, many times closer together than molecules in the gas state. All of the water vapor that filled up the inside of the can turned into only a drop or two of liquid, which took up much less space. This small amount of water cannot exert much pressure on the inside walls of the can, so the pressure of the air pushing from the outside of the can is great enough to crush it. The sudden collapsing of an object toward its center is called an implosion. Hey, air pressure is powerful!


Awesome Science Video

April 7, 2007

Alright, alright. The Honda video is here. The kids have been asking me to post this video for a while… so here it is. Our class spent quite a bit of time analyzing this video for our simple machines unit. The kids really seemed to like the part of the video where the sound waves force the spring to roll off of the windshield. I personally like the part of the video where the fan is blowing just long enough to hit the stand.

A couple of questions for you to consider while watching. One, what’s your favorite part? Two, we debated about the simple machine that the car rolls off of at the end of the commercial. Some said it’s an inclined plane, while some said it’s a lever. What do you think?


Ecosystems

October 13, 2006

In science we have been discussing ecosystems and the organisms within ecosystems. We have also talked about the effects of one wrong move in an ecosystem that could effect many different organisms.

There have been many recent debates about global warming and its effects on ecosystems. Global warming is basically a problem that causes the Earth’s temperature to rise. How do you think global warming will effect cold ecosystems? How will an increased temperature effect organisms living in a cold ecosystem? Finally, although this hasn’t happened yet, how do you know that global warming is good or bad for ecosystems?