History Archive

Why Are Post-it Notes Yellow?

A thought occurred to me as I stared at the Post-it notes on my desk: why are they yellow? I turned to Google, but could find no answer on the web. On the off-chance, I decided to ask 3M – inventors of the Post-it – via Twitter.

After much effort on their part, I received a detailed response via email, which included a transcription of an interview that had been conducted to specifically answer my question:

(23rd February 2010)
HM: Why were Post-it Notes originally yellow?
GN: “Great question – fantastic question. “
“Guess what – we were in the labs and if you imagine, this is my lab here, and then there’s a corridor, and then there’s another lab. They happened to have some scrap yellow paper – laughs – it’s absolutely true. “
“Now afterwards we had a lot of people who said well it’s got a good emotional connection or…” (pauses) “that’s a load of … whatever.”
“They had some scrap yellow paper – that’s why they were yellow; and when we went back and said ‘hey guys, you got any more scrap yellow paper?’ they said ‘you want any more go buy it yourself’, and that’s what we did, and that’s why they were yellow.”
“To me it was another one of those incredible accidents. It was not thought out; nobody said they’d better be yellow rather than white because they would blend in - it was a pure accident.”
“Just like the adhesive was a pure accident. They are the best kinds of accidents to have, but you have to recognise it – which we did.”
HM: “So who actually invented the Post-it note?”
GN: “There were three people. Spence Silver invented the adhesive by accident. He was trying to make – he was in the business of trying to make stronger better adhesives to stick aeroplanes together –  and we do stick aeroplanes together.”
“He came to my office about 48 hours after I joined the commercial tapes division from the overhead projectors part of the business.”
“I’d been made the new products laboratory manager, and they hadn’t had any new products in about 15 years. They hadn’t had a new product since magic tape, and magic tape was about 15 years old.”
“So he knocked on my door. There were two guys – Spence Silver and another guy called Bob Oliveira. They had discovered this adhesive in 1968 – that’s when the patent was filed – and here we are five years later in 1973.”
“He’s saying ‘Geoff would you be interested in this adhesive?’ And I said yes. Why? Because I’m naïve – I’m naïve about adhesives. I don’t know much about it. And I also believe a certain naivety is important. He asked me if I was interested.”
“He had been trying for 5 years to get any business unit interested in this adhesive so he gave me samples and we started playing with things and we started making bulletin boards. “
“As we were making bulletin boards, and tapes and things like that, another guy who worked for me was Art Fry. He was making tapes for skis – ski tape – things like book arranging tape- Things that you’d put on a bookshelf and it would hold books in place”.
“And he said ‘why are you putting the adhesive on a bulletin board. Why don’t you put it on a piece of paper and then we can stick it to anything.’”
“You know – and that was the three of us that came good. And I was in a management role primarily to defend and go fighting for it”.
“When you get down to it with innovation – a lot of people are required to make it successful. Marketing sales, even the accountants.”
“But you sometimes have to fight for it – and that’s inevitable in something that changes the basis of competition. People resist change.”

So there you have it. Not just a fascinating piece of history, but evidence of a company that are willing to go above-and-beyond for no immediate profit or benefit to themselves. 3M (and Hugh in particular), you rock.

Post-it image by Flickr user zarprey

Unorthodox Ships of War

Concrete Ships forming the Kiptopeke Breakwater

During the First World War, steel shortages forced President Wilson to commission the construction of 24 cement war ships. The war ended less than a year later, at which time the first 12 ships were still under construction. These were eventually completed and sold to private companies. Many of them can now be seen slowly decaying off the coast of the U.S., and one has even been converted to a 10 room hotel off the coast of Cuba.

Almost 25 years later, Geoffrey Pyke recommended the construction of a huge aircraft carrier – the equivalent of a floating island – made from ice and wood pulp, during the Second World War. The material, dubbed Pykrete, possesses incredible tensile strength – more than concrete – at less than half the density. The project, named Habakkuk after a biblical quote (“I am going to do something in your days that you would not believe“), underwent a number of prototypes and tests, from secret lairs under Smithfield Market in London, to Lake Louise in Canada, but was never fully realised due to a number of engineering and cost concerns.

Wikipedia recounts an entertaining anecdote about a demonstration of Pykrete’s strength:

… at the Quebec Conference of 1943, Lord Mountbatten brought a block of Pykrete along to demonstrate its potential to the bevy of admirals and generals who had come along with Winston Churchill and Franklin D. Roosevelt. Mountbatten entered the project meeting with two blocks and placed them on the ground. One was a normal ice block and the other was Pykrete. He then drew his service pistol and shot at the first block. It shattered and splintered. Next, he fired at the Pykrete to give an idea of the resistance of that kind of ice to projectiles. The bullet ricocheted off the block, grazing the trouser leg of Admiral Ernest King and ended up in the wall.

Henrietta Lacks and the Tragic Story of Medical Ethics, Racial Politics and Health Care Reform in America


For months, the world has watched eagerly as Obama has tried to navigate the juggernaut of health care reform in the United States. I’m from Canada and I currently live in the United Kingdom, both countries with a long and ardent history of public health care. Maybe that’s why I don’t understand how such a great number of people can be so opposed to the idea that everyone deserves to be able to see a doctor when they are unwell. As recently as today, the Senate is giving no indication of when the watered down Plan B will be passed or when millions of uninsured American citizens can expect some support from their government.

In light of all that is going on with health care reform, Rebecca Skloot‘s book The Immortal Life of Henrietta Lacks becomes all the more poignant, relevant and sad. It’s the true story of a woman who has been largely ignored by the people who write history, despite her involuntary but undeniably great contribution to science over the last century. The reasons for her omission are complex, and no doubt begins and ends with the fact that she was a “poor and largely illiterate Virginia tobacco farmer, the great-great-granddaughter of slaves. Born in 1920, she died from an aggressive cervical cancer at 31, leaving behind five children. No obituaries of Mrs. Lacks appeared in newspapers. She was buried in an unmarked grave.” (source) Her cancer was extremely aggressive and at some point, without her knowledge or consent or that of her family, cells (now called HeLa cells by scientists) were taken from her diseased cervix and have been used as the basis for medical invention for decades.

There are … “trillions more of her cells growing in laboratories now than there ever were in her body.” Laid end to end, the world’s HeLa cells would today wrap around the earth three times. Because HeLa cells reproduced with what the author calls a “mythological intensity,” they could be used in test after test. “They helped with some of the most important advances in medicine: the polio vaccine, chemotherapy, cloning, gene mapping, in vitro fertilization” … HeLa cells were used to learn how nuclear bombs affect humans, and to study herpes, leukemia, Parkinson’s disease and AIDS. They were sent up in the first space missions, to see what becomes of human cells in zero gravity. (source)

The only reason anyone knows about Henrietta Lacks’s contribution is because, decades after her death, doctors began to take blood samples from her surviving relatives to be able to better understand and study HeLa cells. Today, many of her relatives are living in Baltimore and, like Lacks herself did, they struggle to get by. Despite this, they are luckier than Lacks’s daughter who was institutionalised in what must have been a hellish facility – The Hospital for the Negro Insane – where she died at the age of 15. The story defies imagination and inspires disbelief, followed by a combination of anger and horror. According to Skloot’s research, the medical tradition has a long history of experimenting on African Americans in the name of science.

What does this have to do with health care reform?

Says one of Henrietta Lacks surviving sons, “She’s the most important person in the world, and her family is living in poverty. If our mother was so important to science, why can’t we get health insurance?”


The Immortal Life of Henrietta Lacks book jacket image curtosy and copyright of Rebecca Skloot.

Dear Donna – How a Pin Up Girl Joined the Anti-War Movement


Donna Reed was a beautiful American actress who was probably best known for her role as Mary Bailey, the long suffering wife of George in It’s a Wonderful Life. During World War II, she became a very popular pin-up for soldiers overseas – she visited army bases overseas a number of times and corresponded regularly with soldiers on active duty. Although her daughter said she never spoke of the letters she received, when she passed away of cancer in 1986 at age 64, her family found hundreds of these letters stored in her attic:

All told, Ms. Reed held on to 341 letters, some typed but many written in the kind of elegant … method cursive script rarely seen today. Taken as a whole, the correspondence offers a candid glimpse of a vanished era, a time when six hard-bitten Marine sergeants could write that “we think you’re swell” and mean it in something other than an ironic sense … Gauging the impact that the letters had on Ms. Reed is difficult. “I knew she had feelings about her country and participating as a concerned citizen,” Ms. Owen said. But, she added, her mother did not talk about the letters. Ms. Reed lamented to a female pen pal in 1942 that “my effort to win the war hasn’t amounted to much” and “I wish I could find more to do.” (source)

Later in life, and perhaps because of the impact the war and these soldiers in particular had on her, Reed became active in the anti-war movement as a prominent member of the group Another Mother for Peace (AMP). The group is still very active active and shares information such as the recent United Nations report Silence is Violence, End the Abuse of Women in Afghanistan (PDF), encouraging members to act speak, write and act out to encourage peace.

AMP’s Pax Mantra has been a cornerstone for women protesting against war in the United States for decades, including when Reed was a member. This simple, but powerful statement ends, “they shall not send my son to fight another mother’s son. For now, forever, there is no mother who is enemy to another mother.”

Donna Reed image by BooBooGB

Murder Inc. – The Psychology of the Battlefield


The February 2010 issue of Vanity Fair has a great profile on a US military sniper called The Distant Executioner. Although the piece focuses on one man in particular, it delves into the politics and psychology of killing the enemy by sniper fire as opposed to killing at close range during combat.

In 1947 an army general and historian named S.L.A Marshall conducted a study and extensive survey that uncovered that “up to 85 percent of frontline American riflemen had not fired their weapons in combat – even when under attack and at risk of being overrun.”

He attributed low firing rates to an instinctive aversion to killing at close range, when the potential victim is clearly identifiable as another human being. At the vital moment, Marshall wrote, the rifleman becomes a conscientious objector… Numerous independent studies have since found similarly low firing rates among Japanese and German riflemen, as well as among the frontline soldiers of World War I, the American Civil War, and several other conflicts. For whatever reason, the Pentagon took Marshall on faith and initiated a decades-long human improvement campaign. By the Korean War in the 1950s, surveys showed that fully half the frontline riflemen who saw the enemy fired their weapons in response. In Vietnam, the number rose to 90 percent … Of course, to fire at someone is by no means to hit him. The 90 percent figure was undermined by a significant number of intentional misses, and it was inflated by a battle doctrine called ‘Quick Kill’, which taught American soldiers to spray masses of automatic fire rather than take careful aim. As a result of that doctrine, in Vietnam U.S. infantrymen fired 50,000 rounds of ammunition for each kill they made – a ratio that would have encouraged even conscientious objectors to go ahead and shoot.

This all leads up to the discussion on snipers, also referred to as ‘Murder Inc.’. In comparison, snipers with their advantage of being able to kill from a distance expended only 1.39 rounds for every Vietnamese killed.

“Big Gun” Susan image by ttstam.