Posted by: David H. Johnston Saturday January 13, 2007
How do barometers work? Why do meteorologists use barometers? What do barometers do? When were barometers first invented? How do you make a model of a barometer? How accurate are barometers?
Articles 
How Stuff Works
How Stuff Works
How Stuff Works
Posted by: David H. Johnston Sunday February 18, 2007
Global Positioning System satellites transmit signals to equipment on the ground. GPS receivers passively receive satellite signals; they do not transmit. GPS receivers require an unobstructed view of the sky, so they are used only outdoors and they often do not perform well within forested areas or near tall buildings. GPS operations depend on a very accurate time reference, which is provided by atomic clocks at the U.S. Naval Observatory. Each GPS satellite has atomic clocks on board.How do barometers work? Why do meteorologists use barometers? What do barometers do? When were barometers first invented? How do you make a model of a barometer? How accurate are barometers?
Posted by: David H. Johnston Friday October 13, 2006
Posted by: David H. Johnston Wednesday September 20, 2006
Gel-coat is the material which is used to create the glossy colored finish on the hull and deck. It is also the first material that is applied to the form, when building the kayak. Apart from generating the beautiful glossy finish on the kayak, the gel-coat’s function is to protect the fiberglass laminate - the boat’s main material – from moisture.
