Divine thesis: want to know how fast your nails grow? Here are 35 years of data!
Divine thesis: want to know how fast your nails grow? Here are 35 years of data!
How to turn an ordinary thing into an achievement?

how do you turn an ordinary little thing into an achievement? You can try to stick to it for decades.

the protagonist William Bennett Bean (William B Bean) who is going to talk about today is such a persistent person. He is best known for his life-long focus on recording the growth rate of his fingernails, recording 35 years of data and publishing a series of papers.

the titles of these papers are all very straightforward. They are:

Nail growth: 25 years observation

Nail growth: 30 years observation

Nail growth: 35 years observation

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Bean's method of recording nail growth is actually very simple: carve a small horizontal groove on the nail as a mark, then observe the movement of the mark and record when it moves to the "free" position at the end of the finger. He starts a new round of records on the first day of each month, and by the time the paper is published in 35 years, it has been going on for about 450 months. Only twice in the process did he forget to mark his nails on time.

Bean made a lot of interesting findings in the process of observing the growth of fingernails. For example, in the early years, he also measured the clipped nails and found that about 25% to 50% of the nails were actually unconsciously worn off. (you may also know that even if you don't trim your nails after cutting them, the edges of the nails will become very smooth in a few days, which reflects the unintentional wear and tear of the nails).

at first, he measured the growth of fingernails of each finger and toe, and found that these nails seemed to have their own growth pace. Fingernails grow faster than toenails, while the fingernails of the middle finger grow faster. He found that these differences were quite regular, so he later fixed the measurements to the thumb of his left hand and said that the condition of other fingers could be calculated from previous rules.

the 35-year record also clearly shows that the growth rate of fingernails slows down significantly with age. At the age of 32, the measured growth rate of thumb nails is 0.123mm per day, while at the age of 67, the growth rate of fingernails of the same finger becomes 0.095mm.

I have also introduced two other people who focus on doing experiments on their own. One tries to experience where a bee bite hurts the most, and the other insists on using both hands as a control group, and has done a 60-year experiment of snapping his knuckles. For more information, please see here: divine study: what kind of experiment can I do alone?

as an impatient person, I feel that it is very good to persist in doing the same thing for 30 years or 60 years.

here is the original paper of 35 years' observation of nail growth: http://jamanetwork.com/journals/jamainternalmedicine/article-abstract/599478