Most people never give a second thought to life’s most important questions, such as: How tall should a bowling pin be? Fortunately for them, we do. Here’s a look at the standard sizes of everyday objects.

How big is a regular soccer ball?

It must measure between 27 and 28 inches in circumference and weigh 14 to 16 ounces.

What’s the proper size of a dinner napkin?

It should be no less than 183 square inches, unfolded. (A cocktail napkin should be no larger than 100 square inches, unfolded.)

How big does a rock have to be for it to be considered a boulder?

An “official” boulder must be at least 256 millimeters (10.07 inches) in diameter.

How small does a rock have to be for it to be considered a pebble?

A pebble must be no smaller than 4 millimeters (0.16 inch) and no larger than 64 millimeters (2.51 inches) in diameter.

What’s the standard size of a bowling ball?

One should be 27 inches in circumference and weigh no more than 16 pounds.

How big is a bowling pin?

It ought to weigh between 3 pounds, 2 ounces and 3 pounds, 10 ounces and should be exactly 1 foot, 3 inches tall.

What’s the proper size for darts and dartboards?

A dart cannot be more than 1 foot in length, or weigh more than 50 grams. A dartboard must be hung so that the bull’s-eye is 5 feet, 8 inches above the floor. The person throwing the dart must stand 7 feet, 9 1/4 inches from the board.

What’s the right size of a wash cloth?

It’s supposed to be a square of cloth no smaller than 12 by 12 inches and no larger than 14 by 14 inches.

How big is a compact car?

It must weigh at least 3,000 pounds, but no more than 3,500.

 What’s the size of a parachute?

To slow a 200-pound person to a landing speed of 20 feet per second, a parachute must be 28 feet in diameter.

How big is a golf ball?

It must weigh no more than 1.62 ounces, with a diameter no less than 1.68 inches. (A standard tee is 2-1/8 inches long.)

What are the dimensions of a king-size mattress?

It should be no smaller than 80 inches long and 76 inches wide.

How big is a “jumbo” egg?

One dozen jumbo eggs should weigh no less than 30 ounces.

Got more questions about the world and how it works? All will be answered in Portable Press’s Who Knew? The Big Book of Questions That Will Make You Think Again.