No picnic would be perfect without ketchup. But ketchup has this habit of taking its sweet time when leaving the bottle.

There are several ways to get ketchup out of the bottle.

  • Stick a knife in it and scoop it out.
  • Hit the bottle at the neck (where the 57 is located).
  • Skip it and use mustard instead.

But there is a better, scientific way:

Shake the bottle.

Ketchup is made up of tomato pieces, water, vinegar and spices. And, it is the arrangement of the tomato pieces that give ketchup a structure and cause the flow of ketchup to slow down.

Scientists would call ketchup a thixotropic yield stress liquid. The yield stress part means that it takes force for the ketchup to move. This is why we have to hit the bottle to get it out. The thixotropic means that the ketchup has the ability to “remember.”

Once someone has used the ketchup bottle, the ketchup inside “remembers” it and will flow faster afterwards. This means that the second person that gets the ketchup bottle will have an easier time getting the ketchup out then the first person to use it.

What is going is on is that the tomato particles in the ketchup get rearranged after the first use and can easily flow passed each other the second time.

So how do you get ketchup to flow faster? If you are the first person with the ketchup bottle, then shake it. But, if you are the second person, don’t worry; you won’t have long to wait. The ketchup will flow real easily.

So, next time you are at a picnic, let someone deal with the ketchup bottle first. It is polite and scientifically a better way to reduce the wait.


Pi (π) is an old number. It is found in the ratio of a circle’s diameter to its circumference. This might not seem like a big deal for our modern sensibilities, but this was important in the construction of arches for buildings and churches. And, let us not forget the wheel.

Circles are everywhere from wheels of a car, to wheels on a bike, to the shape of a pizza. If you don’t think pizza boxes don’t have to consider pi when making them, you are mistaken. The problem of a circle in a square has perplexed many mathematical geniuses over the centuries.

Talking about mathematicians, they have some funny words to describe pi.  Mathematicians would call pi irrational, which means that you can never find a fraction that is equal to pi.  For ancient people, or for anyone without a calculator, this is maddening. It is nice to be able to simplify pi.  But, there isn’t a way to do that.  For centuries, people looked for a fraction for pi and the closest is  22/7, but this doesn’t exactly equal  pi.  The other weird thing about pi is that it is transcendental, which means it will never be the solution to an algebraic expression.

Pi is a number that is everywhere but it just doesn’t fit in our standard way of thinking about numbers.

Another weird thing about pi is that it goes on for infinity, without end. Computer scientists have calculated pi for billions of digits. Like this …3.14159265358979323846264338327950288419716939937 …  And on and on and on.

The last thing about pi is that it is use in statistics without our knowing. Whenever there is a bell curve shape, the mathematical expression for the bell curve, also known as a normal distribution, has pi in it. That means that pi is not only in every circle you see, but in any poll where an average is taken.

Pi is everywhere, which is why we take a day out of the year to celebrate it.

Happy 3.14!


For those serious about pi:

A history of Pi

A pi-shaped pi pan

When the voice in the commercial says “chocolate melts in your mouth and not in your hands,” well they aren’t joking. Scientifically, it is true. Chocolate melts around 92 degrees Fahrenheit, while your mouth is 98.6 degrees. (Your hands are only 60 degrees.)

Chocolate comes from a seed housed in football-shaped pods, which sprout from a tree called Theobroma cacao. This name literally means food from the gods. This tree grows along the Equator in places like Ghana, Nigeria, the Ivory Coast, Indonesia, Brazil, and Ecuador.

Chocolate is an old food. Montezuma, the ancient Aztec emperor, drank 50 jars of a chocolaty drink to increase his vitality and virility. But, what he drank was very different from the hot cocoa we drink today.

It takes many many steps to make modern chocolate. First, when chocolate farmers open the fruit, the seeds do not look appetizing, that is because the cocoa beans are surrounded by a white gooey mash. “It looks pretty disgusting,” said Gail Ambrosius, a chocolatier based in Madison, Wisconsin. But if you were to taste these beans, you’ll be surprised. “It tastes just amazing. Kind of like honeydew, melon, apricot, peaches. It is just delicious, ” she said.

Once the cocoa beans are taken out, then the transformation begins. The beans are tossed in a large box to ferment, which generates lots of heat—especially after about a week. After that the cocoa beans are laid out on a black tarp to dry. And sorted to remove any stones that might be there. Then, the beans are roasted. “It teases out the final flavor of the beans,” said Ambrosius. The cocoa beans are then crushed and at this point they are called cocoa nibs. And with heat and pressure, you get a drippy melted chocolate, which is called cocoa liquor.

After all of that, a decision has to be made: Are you making a dark chocolate, a milk chocolate, or cocoa powder?

So then you do the math.

“If you’re making a 70 percent chocolate and you’re making a thousand pounds total, you would put 700 pounds of the liquor in your machine and 300 pounds of sugar. So there you get the 70 percent chocolate,” said Ambrosius.

Interestingly, the higher the percentage of cocoa, the healthier the chocolate is. Some studies suggest dark chocolate raises the good cholesterol—and lowers the bad.

But remember, chocolate has lots of sugar—as much as soda. So eat a little bit and savor all the tasty chemistry in your mouth.

The Gateway Arch turned 50 with the help of modern materials and math.

When creating a monument for future generations to behold, there are two features it must possess—simplicity and permanence.  This was the thinking that architect Eero Saarinen used when designing the “Gateway Arch to the West,” which celebrated its 50th anniversary October 28, 2015. Saarinen gained inspiration by looking to the nation’s capital. He surmised that timelessness arose from geometric forms—the Washington Monument is an obelisk; the Lincoln Memorial is a rectangle; and the Jefferson Memorial is a circle in a square. So, Saarinen selected an arch.

However, this arch would be no ordinary arch. Aloft at 630 feet, it had a special geometric form that moved mathematicians and masons—the catenary arch.  A catenary arch appears when a chain hangs freely from two supported ends and occurs in everyday life from draping power lines to necklaces.  When inverted, this arch supports its own weight and differs from a parabola. A catenary arch has steeper legs, a flatter peak, and greater strength. With this appointed shape, Saarinen next sought to find the right building materials to make it.

He chose a material that would represent the modern age—stainless steel. This metal was first created in the 19th century, but perfected in the 20th. It is composed of steel (a combination of iron and carbon) with a dash of chromium. The mix of iron and carbon gives the metal strength, but chromium provides longevity by overcoming iron’s weakness of rusting.

Rust never sleeps, as songwriter Neil Young once penned.  So, the best way to stop it is to prevent it. Paint is one way to halt rust, but an atomic layer of protection helps too. This is where chromium comes in. Chromium makes a thin layer of chromium oxide on the surface, which hinders water from combining with the iron to create rust.

The path to developing the metal for the Gateway Arch was circuitous at best. Stainless steel wasn’t a creation, but an evolution. The discovery of chromium occurred in the 18th century by French chemist Louis Nicolas Vauquelin.  However, the secret to making lasting metals would take some time, as it puzzled some of the world’s greatest minds. Michael Faraday, one of history’s best scientists, began his career investigating new kinds of steel in the 1820s. He had limited success.

Other delays occurred. There were unfiled patents in the 1870s on weather-resistant metals. Then efforts stalled. Two decades later, there was a renewed interest to create stainless steel, but it took a wrong turn. A famous scientist, Sir Robert Hadley, erroneously concluded in the 1890s that chromium lessened steel’s ability to fight corrosion. His unfortunate claim curtailed future work, until Harry Brearley serendipitously uncovered that chromium makes steel “rustless” and commercialized it as cutlery, which was announced in The New York Times in 1915. All these steps together made Saarinen’s Gateway Arch possible.

The stainless steel in the Gateway Arch is the same in a household fork. Metal plates (as thick as four nickels) are held together with miles of welds making the arch’s exterior nearly 900 tons. (For comparison, the Chrysler Building has a 27-ton stainless exterior.) The arch is perched on the edge of the Mississippi where an early trading outpost stood, which was frequented by pioneers, fur traders, and explorers before heading westward. In the 1930s, city leaders wanted to transform this decaying site with a monument to honor those who “won” the west, the Louisiana Purchase, and Thomas Jefferson.

Saarinen’s application in 1947, one of 172 entries including one from his famous architect father, captured what these leaders had envisaged—a message to the future, with modern materials, and a wink to the past, with a simple geometric form. Construction did not begin until 1962. Sadly, Saarinen died of a brain tumor in 1961 and never got to see his structure.

Today, the arch stands strong, although it contends with dirt and chemical pollution from industrial emissions from the arch’s early years. These practices are no longer permissible with the establishment of the Clean Air Act in the 1960s. The survival of the arch is not only a testament to stainless steel but to progressive legislation.  The Gateway Arch continually serves as a material, design, and cultural zeitgeist—relevant to the present, but also connecting us to the past as it propels us upward and forward.