Want to wow your neighbors this Saturday with some bright and cheery Fourth of July trvia? Tell them about the dangers of perchlorate, the molecule that helps fireworks burn longer. According to experts at DMD Systems who study explosive materials, the molecules are not only harmful to the environment, but to humans as well–-and repeated exposure poses health risks.

The good news is that scientists are developing new “green” fireworks--as in environmentally sound, not the color--that burn nitrogen-based fuels. They also use less smoke and contain fewer toxins.

Because solar intensity increases as you get closer to the equator, the same solar cell normally can't be equally effective in any given location. The UK firm Quantasol has devised a way of allowing solar cells to be fine-tuned according to their positional latitude, providing a substantial bump in efficiency.

Now that every scientist who isn't part of the lunatic fringe agrees that human greenhouse gas emissions significantly alter the world's climate, the debate on Capitol Hill has shifted from science to policy. And that debate has proved even more complex than Congressional fights over the stimulus package, car company bailouts, and the decision to invade Iraq.

On Friday, the House of Representatives passed HR 2454, the American Clean Energy and Security Act of 2009, by a margin of 219 to 212, with three abstentions. The bill is the first legislative attempt to regulate carbon emissions, and the first bill to directly finger humans as the cause of climate change.

Scientists have repeatedly touted the possibility of turning algae into biofuels. Now a Florida-based company called Algenol is working with Dow Labs in Texas to convert carbon dioxide produced by algae farms into ethanol, which will then be used to make plastics. Even better, the oxygen byproduct left over from the conversion can be used to produce cleaner, more efficient coal power.

Using one of the most clever names in tech history, Microsoft has announced Hohm (which telescopes home into ohm), a new Web-based service for keeping an eye on your smart grid. The beta for the service goes live next week; users can sign up to access the service at microsoft-hohm.com.

Trees are great absorbers of carbon dioxide from the atmosphere, and inhibitors of climate change -- that's why treehuggers hug them so much. But leave it to humanity to engineer a better tree. A synthetic tree, currently being tested as a prototype, ensnares carbon about 1,000 times faster than a real tree.

Solar power is an exciting source of renewable energy, but has so far mostly been used to power little things like homes, cars and small villages. But what if solar energy was used on a scale that would power the majority of Europe?