Heard they put people on the moon with these and now I see how, thanks for making the baffling approachable sir

@sliderulesandmathematics9232

Ай бұрын

My pleasure and they did

Thank you, Bob, very much for your video. Regarding 1:22, I really like your suggestion of using the slide rule gauge mark R = 57.3° per radian as a mnemonic for also remembering that the half-life of Carbon-14 is 5,730 years. I have added this to my notebook on slide rules..

@sliderulesandmathematics9232

Ай бұрын

Glad to hear you enjoyed it

The halflife of C14 is 5700±30 years. Is there an easy way on the slide rule to give readings for the ±30 years bounds?

@sliderulesandmathematics9232

Ай бұрын

The third sig dig is an estimate anyhow

@RensePosthumus

Ай бұрын

@@sliderulesandmathematics9232@sliderulesandmathematics9232 Yes, I know, but if I was referring to the principle, essentially how to do calculations with an upper/lower bound. The tabulation is great for point values, but is there an easy form of doing tabulation on a range?

@sliderulesandmathematics9232

Ай бұрын

I would say get you answer and add the +/- 30 per half life. Do you have any ideas?

@RensePosthumus

Ай бұрын

@@sliderulesandmathematics9232 just adding 30 doesnot work. See back of the envelope calculation lb=5700-30 ->c_lb=1.22*10^-4 (c_lb=ln(0.5)/lb) ub=5700+30 ->c_ub=1.21*10^-4 (c_ub=ln(0.5)/ub) c_lb:10% left ->t=-ln(10)/-c_lb = 18.873 c_ub:10% left ->t=-ln(10)/-c_ub = 19.029 if was thinking to do some additional arithmetic with k=(5700-30)/(5700+30) but I need some time to figure it out

@JohnLeePettimoreIII

Ай бұрын

@@RensePosthumus i would think that when dealing with > 5700 years, +- 30 would simply be "noise in the signal". the way i see it, variance due to many unknown factors would make the +- just vanish. but then, if you're looking for more than about 3 (or perhaps 4) significant digits, you probably don't want to be using a slide rule.

If you had a sample with only 1% C14 remaining, shouldn't you be looking for a different radiometric dating method?

@sliderulesandmathematics9232

Ай бұрын

Good point but we can still accurate get out to 40-50k years with C14

so if i am following you correctly, 40% remaining would indicate about 7,520-ish years.

@sliderulesandmathematics9232

Ай бұрын

Using the 20” aristo studio I got 7570 years, so well done. The difference could be accounted for by very minor errors in cursor placement. Also, depending on the graduations between 7.5 and 7.6 (ie 2 on the n3 vs 5 on the 20”) that could account for it as well. Bottom line you did it right and got a good answer

@sliderulesandmathematics9232

Ай бұрын

“Slide rule accuracy” is generally +\- 2 at the 3rd significant digit for a 10” rule

@JohnLeePettimoreIII

Ай бұрын

@@sliderulesandmathematics9232 groovy. in that case, i think i am starting to wrap my brain around some of these more esoteric bits. a testament to your teaching style. thank you.

@sliderulesandmathematics9232

Ай бұрын

glad you enjoyed it!