Back in high school, I was in a college-bowl style competition (team, buzzers, timers, etc.) that covered the span of general knowledge taught in science, math, English and history classes.
One of the questions asked was, “What is Avogadro’s Constant?” The competing team hit the buzzer first and answered, “6.2 times 10 to the 23rd power.”
When the moderator said, “That’s correct for 40 points”, I jumped out of my seat and yelled, “No! The correct value is 6.02 times 10 to the 23rd power.”
I then added, “In fact, it’s 6.02252 times 10 to the 23rd power!” The chemistry teacher agreed, the moderator canceled the question, and the points were taken back.
My team ended up winning the competition by a mere 10 points. Thank you, Amedeo!
When I got to college, that “constant” had changed to 6.022045 10^23. Over the decades, it changed again and again, and just recently I read that it is now a constant of 6.0221413 10^23.
Avogadro’s Constant is a fact. It’s consistent. Stable. Steady. Unvarying. Steadfast. Unchanging!