Astro Bob A look at celestial happenings in the Northland and beyond Bob King View my profile Click here to view previous posts or additional resources

Hope you enjoyed your brush with the periodic table

Duluth's firework show attracted thousands last night. The red color is from burning lithium or strontium carbonate; the blue from copper. The building at right is a performance stage. Photo: Bob King

Hope you had a great 4th of July celebration yesterday. I was working, but got to partake in the fun by attending Duluth's "Fourth Fest" along the harbor. The fireworks were wonderful as they always are, and the sky cleared enough to see Venus in the west. Concealed fireworks afficianados in the hillside opposite the bay started the show early with their own modest display of pyrotechnics. They had a captive audience of thousands who waited until 10:10 p.m. when the city show started.

The planet Venus is framed by smaller-scale fireworks launched by enthusiasts in

Duluth's hillside. Photo: Bob King

The colors of fireworks are fascinating and created using specific elements and compounds. An element is a pure substance consisting of one type of atom. Carbon is only made of only carbon atoms and nothing else; each carbon atom has exactly six protons in its nucleus, a number chemists call its atomic number. Similarly, oxygen's atomic number is 8, calcium 20 and uranium 92. Elements like helium and lithium, which have only 2 and 3 protons respectively, are very light. Gold is heavy because each atom packs 79 protons. Compounds are chemicals consisting of two or more elements in combination.

Pyrotechnicians create all the colors of a show using key elements bound in chemical compounds. Those beautiful golden waterfalls come from the burning of iron, white from aluminum and titanium powders, green from barium and red from strontium and lithium. It's a virtual periodic table of elements at work up there every July 4.

There are 118 known elements, which include about 26 manmade ones. Many of the "synthetic" elements are created by bombarding a heavy element like uranium with alpha particles (a form of helium) to build bigger, heavier ones like plutonium. Even larger ones up to Ununoctium , element 118, are created by fusing plutonium with smaller elements. The heaviest natural element is uranium with 92 protons. Beyond uranium, all manmade elements are unstable or radioactive and decay into other elements over time.

Lyle Anderson of Duluth has been busy in the early morning hours with his camera and sent these two photos of over the weekend of the moon and the International Space Station. Thanks Lyle for keeping us in touch with events of the night!

The International Space Station cruises through the treetops early last Friday morning. Tomorrow I'll update you on when to watch for the station for the remainder of the week. Credit: Lyle Anderson

The last quarter moon and the planet Jupiter (lower right) early on the morning of the 4th. The moon is now a thick crescent and rises around 1 in the morning. Credit: Lyle Anderson

Posted by: rking@duluthnews.com on 7/5/2010 at 11:52 AM | Comments (0) | Permalink | Edit

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