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OMSI in Portland Oregon in the USA has a public and free solar charging station for any electronic devices (lockers keep the devices safe), cars and even electric bicycles. It's owned by OMSI though so maybe that's why they think the Belgrade station is the "first" public charging station.

Another local example: Portland Community College is pcc.edu. PCC isn't a 4-year school, so it properly should be cc.portland.or.us

I was in a museum recently where they had an exhibit about Hanford. Yes, a lot of the nasty stuff was basically stored in single-wall steel tanks not unlike oil storage tanks. As time has passed, many have rusted through and released plumes of really bad gunk into the groundwater.

I live down in Eugene, but visit Portland quite often. OMSI is a great science center, with an IMAX theater and a large area for kids to play. There's a top-notch zoo and Children's museum.

It does have it's big city problems, however. Traffic can be pretty bad and I managed to get assaulted there once. Eugene has most of the big city amenities without the big city problems.

Also, I remember reading a while ago that the earth's helium resources are pretty limited. Any helium that escapes into the atmosphere isn't coming back. Ever.

So, once we use the helium we have, we aren't getting any more. One source says this may happen by 2030.

Found some googled info here and here and here.

Right, a simple test case is a good way to prove the concept. So let's do it!

Let's immagine a very simple baloon that only picks itself up and then falls down. We will cheat a little by having compressed H/He available on the ground. We will imagine our baloon has some structural weight, W, and that it's large enough to have bouyancy to lift that W. Our baloon must have a pump and a tank inside so that the boyancy can be reduced so the baloon can decend. The only energy we need, then, is enough energy to reduce the volume of H/He enough to descend. The energy available is mgh, or Wh the weight times the height. If, like most baloons, we can take it to the edge of space there should be plenty of energy available to compress our H/He. The only practical problem is capturing that energy. So, how much energy would we need to capture?

A 5Kg mass taken to 10,000m would give us about half a million joules. Givent the relative densities of air and H/He, we will need between 4 and 5 cubic meters of gas to lift 5Kg. It would take, roughly, 250,000 joules to compress that volume by half and give you 2.5 Kg of downward force. Oh dear, at 10,000m this is looking like a wash out. Fortunately, manned balloon flight can get to 30,000m, so this is theoretically possible. Just don't try to do it like this

Incidentally, if you go and see if a feature film playing at an IMAX theater, make sure to get there early: we got seats that were just slightly off center and closer to the floor. The experience was painful, and not just because of the dialogue. (Although they did cut out the scene in the fields)

Getting kids involved with something "real" (insert "tangible" or "active" if you like) is one of the best ways I've found to get them interested (as a student and an instructor). Here's some stuff I did while teaching at summer day camps at the Capital Children's Museum a couple of years ago:

• Baking muffins to learn why breads have holes, and figuring out why one recipe used baking soda and one used baking powder (kitchen chemistry, as well as some acid-base stuff);
  
• Figuring out whether normal, dried or soaked popcorn kernels pop best (including taste-testing), and freezing ice cream using baggies, rock salt and ice (solids/liquids/gases)
  
• Making three kinds of "slime" (or gak or flubber) and explaining what non-Newtonian fluids are (my second-graders showed up some adults!)
  

Try these sites to get some ideas:

• The JASON project was started by Dr. Robert Ballard (the guy who discovered the Titanic and other sunken ships)
  
• Local colleges and high schools often present chemistry shows (or physics/science shows). Here's a plug for my alma mater: Lawrence University). I swear the show is more entertaining than the description on that page.
  
• PBS is full of things, including a show called ZOOM!, the ever-popular Newton's Apple, and wacky Bill Nye the Science Guy.
  
• At the U of W Madison, Prof. Shakhashiri created THE definitive books of demonstrations (Caution: he's kind of dry, but the demos are great!)
  
• Science museums also often have some sort of hands-on stuff. Go ahead and "borrow" from them! Here's the Oregon Museum of Science and Industry and the Science Museum of Minnesota
  

Good luck!

Or a sphere, floating in the air...

Brings a whole new meaning to the term, Bernoulli Drive.

ditched it. I'm the webmaster at OMSI but I'm not in the IS department who were the main implementors. Rulespace is a local company and was thinking of using OMSI as a testbed for beta versions of their software. They told us about their AOL deal and about some of their other clients including a huge beer company. This was about 1.5 years ago. We ran the software for about 9 months ending in September 2000 or so. We got rid of Rulespace for three main reasons: 1. At the time, their software did not feature different types of users - some people need to see certain sites while others should be blocked. 2. We found that the added overhead was unacceptable. Hopefully AOL has some extremely fast servers. 3. The number of false positives was unacceptable. They claim neural net software, but the way it was implemented at OMSI resembled a keyword search with an exception list of urls. I was incorrectly blocked at least once a day (although I do use the web a lot more than most other staff members). Also, there were some sites that definitely should have been blocked but were not. mark -- Mark Chen | Webmaster | Oregon Museum of Science and Industry | www.omsi.edu

ditched it. I'm the webmaster at OMSI but I'm not in the IS department who were the main implementors. Rulespace is a local company and was thinking of using OMSI as a testbed for beta versions of their software. They told us about their AOL deal and about some of their other clients including a huge beer company. This was about 1.5 years ago. We ran the software for about 9 months ending in September 2000 or so. We got rid of Rulespace for three main reasons: 1. At the time, their software did not feature different types of users - some people need to see certain sites while others should be blocked. 2. We found that the added overhead was unacceptable. Hopefully AOL has some extremely fast servers. 3. The number of false positives was unacceptable. They claim neural net software, but the way it was implemented at OMSI resembled a keyword search with an exception list of urls. I was incorrectly blocked at least once a day (although I do use the web a lot more than most other staff members). Also, there were some sites that definitely should have been blocked but were not. mark -- Mark Chen | Webmaster | Oregon Museum of Science and Industry | www.omsi.edu