What is the most common reference material when measuring the Specific Gravity of a substance?

More Questions:

Traditional Scottish Highland Games feature which event where competitors throw a tapered 19 foot and 6 inch long log?

In popular culture, what is a "Tamagotchi"?

What fish is known as poor mans lobster?

What is a "rosti"?

What American Revolution spy is the official state hero of Connecticut?

How tall is a regulation adult soccer goal?

With which team did Brett Favre start his professional football career in 1991?

What forest was home to Robin Hood and his band of Merry Men?

Which of the Three Tenors lived in Mexico from the age of eight?

What country is Dinish Island a part of?

What is the Latin name for a guinea pig?

Which 1995 movie stars Susan Sarandon and Sean Penn?

Who was the lead singer of "The Crickets"?

What skateboarding actor-to-be plays the main character in Sonic Youth's music video for "100%"?

In which century did the English Civil War take place?