41

Scheduled to be completed in 2021, the Riverfront Square in Newark includes a 500,000 sq-ft tower that will be among the largest structures in the U.S. to be made of wood. 

It takes 20 mature Douglas Fir trees to build 1,000 sq-ft of home. It takes 60 years for a Douglas Fir to become full grown.

If the Riverfront Square were made entirely of Douglas Fir, how many Douglas Fir trees are needed?

42

The common swift, weighing just 1.5 ounces and has a wingspan of 16 inches, holds the record for the longest continuous flight time of any bird. A study has found these birds flying for 10 straight months without ever stopping!

The Earth's circumference is 24,901 miles. The common swift can fly at a speed of 70 mi/h.

At this speed, approximately how many days would it take for the common swift to fly once around Earth's equator?

43

Mercury metal (Hg) has a density of 13,593 kg/m^3. Its unique properties -- the only metal in a liquid state at room temperature, high boiling point, high coefficient of expansion -- make it very suitable in thermometers. 

​Lithium (Li) is the least dense metal at 0.534 g/cm^3. (Water has a density of 1.0 g/cm^3.) As a lithium salt, it is used to treat bipolar disorder and other major depressive disorders. 

Compare the densities of mercury to lithium.

44

The Nile is the world's longest river at 4,132 miles. It flows northward through eastern Africa and into the Mediterranean Sea.

The Roe River is in Montana and is the world's shortest at 201 feet. 

There are 5,280 feet in a mile. What is the length of the Nile to the Roe River?

45

The volume of the Earth's oceans is estimated to be 352 quintillion gallons of water, that's 352 x 10^18 gallons.

The area of the U.S. is 3.797 million square miles. One cubic mile could hold 1.1 trillion gallons. 

Pretend we could pour the ocean's water onto the U.S. and there's an infinitely tall edge all around to hold in the water, how many miles deep would the water be?

46

Echolocation is the use of sound waves and echoes that bats and whales use to navigate and find food. A sperm whale can "see" objects via echolocation from 500 meters away.

A human with "normal" or 20/20 vision can clearly see something from 20 feet away. 

How many times farther can a sperm whale "see" compared to a human?

47

In the U.S., the average LCD TV screen is 47 in, this is the diagonal length of the screen.

The Dallas Cowboys play their home games at the AT&T stadium which has two massive jumbotron screens. Each screen is 160 feet wide and 72 feet tall.

How much longer is the diagonal length of the jumbotron to the average TV?

48

Radiometric dating and other scientific evidence suggest that Earth is 4.543 billion years old.

Let's say that the birth of the U.S. was when the Declaration of Independence was ratified by Congress on July 4, 1776.

If we scaled down Earth's age to 100 years, then relatively speaking, how old is the U.S. in minutes?

49

One liter of helium can lift 1 gram. A normal party balloon can lift about 14 grams.

The movie Up, produced by Pixar and released by Disney in 2009, was an animation about a house being flown around by a ginormous bundle of balloons. 

How many party balloons would it take to lift a 50,000-kg house?

50

The record for the slowest selling book goes to David Wilkins’ translation of the New Testament. It was published in 1716. On average, one book gets sold every 20 weeks.

Harry Potter and the Deathly Hallows by JK Rowling holds the record of selling the fastest at 15 million copies within 24 hours on July 21, 2007 in the U.S. 

What is the sales rate of Rowling's book to Wilkins' translation?