Aircraft

An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.

The human activity that surrounds aircraft is called aviation. Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others.

History

Flying model craft and stories of manned flight go back many centuries, however the first manned ascent – and safe descent – in modern times took place by hot-air balloon in the 18th century. Each of the two World Wars led to great technical advances. Consequently, the history of aircraft can be divided into five eras:

Imagination Station

Imagination Station (formerly the Center of Science and Industry (COSI)) is a non-profit, hands-on science museum located on the riverfront in downtown Toledo, Ohio. The facility has over 300 exhibits for "children of all ages."

After tax levies failed in 2006 and 2007, COSI closed its doors to the public on the last day of 2007 due to lack of funding. In 2008, voters approved an operating levy to reopen the facility using The Toledo Science Center as its interim name. The Imagination Station opened on 10 October 2009.

History

In 1984, the Portside Festival Marketplace shopping mall opened along the Maumee River, on the site of the former Tiedtke's department store, with the hope of revitalizing downtown Toledo. In 1990, the marketplace closed, leaving a vacant 100,000-square-foot (9,300 m²) modern facility. A committee, appointed by the mayor, was charged with finding the best use for the site. Researching options, committee members heard repeatedly the need for an educational family attraction. As a result, COSI Columbus was approached regarding the development of a similar institution in Toledo. Together, a structure was developed making COSI Toledo an independent, not-for-profit organization with a board of trustees from Northwest Ohio, while taking advantage of the experience and resources of COSI Columbus.

Sulfur hexafluoride

Sulfur hexafluoride (SF₆) is an inorganic, colorless, odorless, non-flammable, extremely potent greenhouse gas which is an excellent electrical insulator.SF
6 has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. It is a hypervalent molecule. Typical for a nonpolar gas, it is poorly soluble in water but soluble in nonpolar organic solvents. It is generally transported as a liquefied compressed gas. It has a density of 6.12 g/L at sea level conditions, which is considerably higher than the density of air (1.225 g/L).

Synthesis and reactions

SF
6 can be prepared from the elements through exposure of S
8 to F
2. This was also the method used by the discoverers Henri Moissan and Paul Lebeau in 1901. Some other sulfur fluorides are cogenerated, but these are removed by heating the mixture to disproportionate any S
2F
10 (which is highly toxic) and then scrubbing the product with NaOH to destroy remaining SF
4.

There is virtually no reaction chemistry for SF
6. A main contribution to the inertness of SF₆ is the steric hindrance of the sulfur atom, whereas its heavier group 16 counterparts, such as SeF₆ are more reactive than SF₆ as a result of less steric hindrance (See hydrolysis example). It does not react with molten sodium below its boiling point, but reacts exothermically with lithium.

Steve Spangler

Steve Spangler (born December 8, 1966) is a television personality, author and science teacher. Spangler founded Steve Spangler Science and its wholesale division, Be Amazing Toys. He serves as CEO of Steve Spangler Science and the creative director of Be Amazing Toys. Both companies develop science education teaching tools and toys. Spangler posted the first Diet Coke and Mentos video on YouTube in September 2005 and his 2002 televised demonstration of the eruption went viral launching a chain of several other Diet Coke and Mentos experiment viral videos. He earned two Heartland Emmy Awards and a total of five Emmy nominations. Spangler holds a Guinness World Record for the largest physics lesson and is an inductee of the National Speakers Association Speaker Hall of Fame.

Career

Education work

Spangler's career began as a science teacher in the Cherry Creek School District in Colorado. As part of a science outreach program, Spangler created a traveling science show targeted to elementary and middle school students in an effort to increase interest in science. In 1991, Spangler began traveling throughout Colorado and the surrounding states to present school assembly programs and teacher training workshops focused on using more inquiry-based science activities in the classroom.