ENDS IN "FF"
It starts a football game
a kickoff
The number of American colonies at the time of the Revolution plus the number of states today
63
In North Africa, it's Arabic for "the victorious"
Cairo
The Department of Energy says homes employing this water heating method can save 50% on their bills
solar energy
A roentgen is a unit of measure of the amount of exposure to these, discovered by Roentgen
X-rays
To scrape up your shoes
scuff
The number of countries that begin with Q times the number of countries that begin with X
0
University city 60 miles up the M11 from London
Cambridge
100-foot-tall towers grouped in "farms" are used to create this type of power
wind
Silicon & germanium are examples of these materials with resistivity between that of conductors & insulators
semiconductors
This Arizona city is home to Lowell Observatory, from where Pluto was discovered
Flagstaff
The number of Great Lakes times the number of countries that border the United States
10
Rome razed it in 146 B.C.
Carthage
Fuel cells made of this most abundant element in the galaxy powered the Space Shuttles
hydrogen
The gears in a clock are examples of the simple machine called a wheel & this
an axle
It's another name for the pope
the pontiff
The number of continents minus the number of mountains above 29,000 feet
6
You'll find a great American--heck, the Great American Ball Park in this city on the Ohio River
Cincinnati
Hydroelectric power employs rushing water passing through these rotored machines that turn generators
turbines
Ground effects on race cars are to keep the tires on the track, fighting this 4-letter force that tries to raise them
lift
This officer, from the Old French for "custody", maintains order in a courtroom
a bailiff
The number of U.S. states on the Pacific Ocean squared
25
One of the world's largest freshwater aquariums is in this city on the Tennessee River
Chattanooga
This 7-letter word can refer to the total weight of one plant species or to plant material used as fuel
biomass
A subatomic particle consisting of a quark & an antiquark, the J particle is also called by this Greek-letter name
psi