The Surprising Reasons Why Common Items Are A Certain Color

Originally, most barns in the United States were unpainted. Farmers didn't have extra money to spend on luxuries such as making a building pretty. 

But the untreated wood had many downsides, like breaking down in the elements more quickly. So farmers used what was around them to make the cheapest coating they could. They ended up creating a mixture that consisted of linseed oil (from flax plants), milk, lime, and iron oxide (from the soil). The iron oxide has a particular rusty color that ended up giving the barns their red look. 

And this “paint” ended up having even more benefits. The iron oxide kept moss and fungi from growing on the barn. And the rich color absorbed the sun's rays far more than untreated wood - leading the barns to be warmer in the colder months. 

Since it was cheap and efficient to have a red barn, more farmers started following suit - until it became the iconic sight we're familiar with today. 

Before there were traffic lights, there were railway lights. Back then, red meant “stop," white meant “go," and green meant “slow.” 

Red was the easiest to see from far away because it has the longest wavelength of any color. Train conductors thus had ample notice if they needed to begin to slow down. Red, therefore, continues to signify “stop.” 

White meaning “go,” however, had a few problems. First, if the green-colored cap fell off the “caution” light, it would look white to conductors, and they'd drive full steam ahead. Or if it was an extra clear night, conductors might mistake a bright star in the distance for the white “all clear” light. 

So railway companies adopted green for “go” instead; and yellow eventually was used for “slow down” because it's easily distinguishable from other colors. 

One of the most popular style of pants in the world is “blue jeans.” The color of the fabric is so integral that it's actually become part of the name. But why does denim have that signature blue color? 

The answer comes down to comfort. Back in the 1870s during the Gold Rush, prospectors were looking for durable clothes to wear as they panned for gold. Levi Strauss and Jacob Davis created an indigo-washed dungaree that quickly began outselling all other options. 

The reason? The indigo they used to dye the denim would bind to the cloth's threads. When it was washed, some of this dye, along with loose threads, were stripped away. This softened the denim, making it more comfortable to wear the longer you owned it. (As many of us can still attest to today.) 

United States cash has had a green tint for quite some time. Before the Civil War, money was printed by private banks or state-backed institutions, so cash came in a variety of sizes and colors. Counterfeiters would scratch off the amount listed on a bill and add their own number, or take a photograph of a bill, passing it off as a real one. 

However, this all changed during the Civil War, when the US federal government started printing money to support war efforts. To get around counterfeiters, one side of the bill was printed with green and black ink. This green ink was less likely to fade, and couldn't simply have a photo taken of it (because photos were black-and-white at the time). 

Even after the war, the government kept with the green ink because it came to represent the stability of the US dollar, and was cheap and readily available. 

The color of a tennis ball is so unique that most of us would just label it as "tennis ball neon." It's not quite yellow, but not quite green - living in its own, specific spectrum of color. 

Whatever you call the color, the hue is undeniably ubiquitous in the sport of tennis. It's hard to imagine the ball could be any color other than that bright, jarring green-yellow shade. 

However, this color is a fairly recent development in the history of tennis. From the 1870s to the 1970s, tennis balls were either black or white. This didn't pose an issue until networks decided that they wanted to air tennis on television in color. (Famed documentarian David Attenborough was actually one of the first to fight for Wimbledon being broadcast in color in the late 1960s.)

However, the at-home audience quickly realized that they couldn't follow the ball when it was near the white lines outlining the court. After some research, the International Tennis Federation found that yellow balls were the easiest to see, and the color was adopted for tennis balls in 1972. 

Better visibility for fans was also why the basketball was changed from brown to orange in the 1950s. 

Bubble gum is what you'd consider an “accidental discovery.” In Philadelphia during the 1920s, Walter E. Diemer worked as an accountant at a chewing gum property. But Diemer didn't just stick to the numbers; he would try out new chewing gum recipes in his free time. 

One day, he accidentally created a substance that was thin enough to blow bubbles, but not sticky enough to stick to your teeth. 

As Diemer said: 

It was an accident. I was doing something else and ended up with something with bubbles.

He dubbed it “Dubble Bubble,” and sent a shipment to a local candy store, where it sold out within a day. 

So why did Diemer choose pink as the flavor of his new creation? Because it was the only food coloring dye he had access to at the factory.