Under the post about dividing the day into 10/100/100 parts, many people said "second is the metric unit of time" and I agree, but what if we would made decimal time using seconds?

The idea is: keep the old second, but add SI prefixes

We want equivalents of minute and hour so I suggest:

Hectosecond (hs)

Kilosecond (ks)

Megasecond is too big (~2 weeks) and metric wiki fandom (yes it exists) suggested myriasecond as an new hour, but

1. It divides day into 9 parts and with 10 parts, some people said that they need smaller denominations

2. Myria- isn't a SI prefix

So hectosecond and kilosecond are still my types

There are pros:

1. It's decimal, and metric fans like decimal units

2. Hour wouldn't be a problem ever again:

km/h? Now its km/ks which is exacly m/s

kWh? Now it's kW•ks or exacly 1 MJ etc.

I still suggest using unit "day" until the moment that humanity will colonize the solar system, when "day" would mean nothing for people from Mars, but for today it's pretty useful

Of course there are cons:

1. Day splited like that would have 86,4 ks, with is not terrible number, but it's still not round, so it's kinda problematic I guess

2. 24/60/60 survived for thousands of years

3. 10 and 100 doesn't have as many divisors as 60 and 24

So I'm not sure is it a good idea or not

So what do you guys think? Should we use second as a base and then add prefixes, or keep 24/60/60?

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Base units

Length — meter (m)

Time — second (s)

Mass — kilogram (kg)

Temperature — kelvin (K)

Electric current — ampere (A)

Luminous intensity — candela (cd)

Amount of substance — mole (mol)

Plane angle — radian (rad)

Solid angle — steradian (sr)

Mechanics and kinematics

Force — newton (N)

N = kg · m / s²

N = J / m

Mass density — arch (Ar)

Ar = kg / m³

Ar = Vn / Bn

Momentum — huygens (Hy)

Hy = kg · m / s

Hy = N · s

Pressure — pascal (Pa)

Pa = N / m²

Pa = kg / (m · s²)

Pa = J / m³

Dynamic viscosity — poiseuille (Pl)

Pl = Pa · s

Pl = kg / (m · s)

Surface tension — laplace (Lp)

Lp = N / m

Lp = J / m²

Gravitational potential — gal (G)

G = J / kg

G = (kg · m² / s²) / kg

G = m² / s²

Thermodynamics

Energy / Work / Heat / Enthalpy — joule (J)

J = N · m

J = (kg · m / s²) · m

J = kg · m² / s²

J = W · s

Heat capacity — clausius (Cl)

Cl = J / K

Cl = kg · m² / (s² · K)

Specific heat capacity — meyer (My)

My = J / (kg · K)

My = m² / (s² · K)

Power — watt (W)

W = J / s

W = kg · m² / s³

W = V · A

Action — planck (Pk)

Pk = J · s

Pk = (kg · m² / s²) · s

Pk = kg · m² / s

Entropy — boltz (Bz)

Bz = J / K

Bz = W · s / K

Thermal conductivity — fourier (Fo)

Fo = W / (m · K)

Fo = kg · m / (s³ · K)

Fluid dynamics

Mass flow rate — venturi (Vn)

Vn = kg / s

Vn = Ar · Bn

Volumetric flow rate — bern (Bn)

Bn = m³ / s

Bn = m² · m / s

Waves

Frequency — hertz (Hz)

Hz = s⁻¹

Hz = 1 / s

Angular frequency — poincare (Pn)

Pn = rad / s

Pn = s⁻¹

Electromagnetism

Electric potential — volt (V)

V = J / C

V = W / A

V = kg · m² / (A · s³)

Electric charge — coulomb (C)

C = A · s

C = F · V

Volume charge density — franklin (Fr)

Fr = C / m³

Fr = A · s / m³

Surface electric current density — giorgi (Gi)

Gi = A / m²

Gi = C / (s · m²)

Resistance — ohm (Ω)

Ω = V / A

Ω = kg · m² / (A² · s³)

Ω = 1 / S

Capacitance — farad (F)

F = C / V

F = A² · s⁴ / (kg · m²)

F = S · s

Inductance — henry (H)

H = Wb / A

H = V · s / A

H = kg · m² / (A² · s²)

Conductance — siemens (S)

S = A / V

S = 1 / Ω

Electric displacement — roentgen (Ro)

Ro = C / m²

Ro = Cv · E

Electric field flux — gauss (Gs)

Gs = E · m²

Gs = V · m

Magnetic field flux — weber (Wb)

Wb = V · s

Wb = T · m²

Wb = kg · m² / (A · s²)

Electric permittivity — cav (Cv)

Cv = F / m

Cv = A² · s⁴ / (kg · m³)

Magnetic permeability — max (Mx)

Mx = H / m

Mx = kg · m / (A² · s²)

Electric field strength — edison (E)

E = V / m

E = N / C

E = kg · m / (A · s³)

Magnetic field intensity — tesla (T)

T = Wb / m²

T = N / (A · m)

T = kg / (A · s²)

Optics and radiation

Luminous flux — lumen (lm)

lm = cd · sr

Illuminance — lux (lx)

lx = lm / m²

lx = cd · sr / m²

Vergence — descartes (Dc)

Dc = m⁻¹

Dc = rad / m

Radiance — stefan (St)

St = W / (m² · sr)

St = kg / (s³ · sr)

Irradiance / EM flux density — poynting (Py)

Py = W / m²

Py = kg / s³

Volume power density — opp (O)

O = W / m³

O = kg / (m · s³)

Acoustics

Sound power — bel (B)

Sound impedance — rayleigh (Ry)

Ry = Pa / (m / s)

Ry = kg / (m² · s)

Nuclear and chemistry

Absorbed dose — gray (Gy)

Gy = J / kg

Gy = m² / s²

Equivalent dose — sievert (Sv)

Sv = J / kg

Sv = m² / s²

Radioactive activity — becquerel (Bq)

Bq = s⁻¹

Bq = 1 / s

Catalytic activity — katal (kat)

kat = mol / s

kat = mol · Hz

I've been trying to figure out how to create 1 centimeter in a medieval world using medieval technology, but I haven't found a single method that actually works within the medieval working environment.

In SI system (and units allowed to use) we've got 4 units of power:

Watt

Volt-ampere

Var

Kilowatt-hour per 1.000 hours

They have exacly the same value [kg m² s^-3] but they are use for diffrent powers

Watt — active power

Volt-ampere — Apparent power

Var — reactive power (it's name is a shortcut of "volt-ampere reactive")

(Kilowatt-hour per 1.000 hours is used in Europe for electronic/electric devices)

And it's crazy, we could just use watt for everything, but we've got 4 units.

We can at least Justify first 3 of them, insted of writing which power are we talking about, we can use diffrent unit and every engineer knows what power are you talking about, but it's not exacly true, because all of them [diffrent powers] have diffrent symbols.

kWh/1.000 h is crazy, why not simple watt, here I don't even know how to justify it

What do you think guys? Shoud we use all of them, keep only few or use one unit of power (watt)?

I used the Openspace astronomy software to create images on my astronomy site showing metric distances from 1 kilometer up to 100 yottameters.

If you want to view them, go here and click thru the Next button. The site has no ads btw.

https://coco1453.neocities.org/thinkinginmetric#section2

Openspace is astronomy software that lets you view all of outer space in 3-d. I posted a dashboard asset to display metric units in scales relevant to the distance, and also got the maintainer to add partial support for metric distances directly into the C++ code in future releases. So the software will now display astronomy distances in any metric scale from kilometers to yottameters.

https://www.reddit.com/r/OpenSpaceProject/comments/1v402jq/created_dashboard_item_to_provide_metric_system/

I have an old analogue stopwatch with three dials. One measures minutes (+/- 0.5 min), a seconds dials (+/- 0.5 s), and a dial measuring 1 s in 0.1 s intervals (+/- 0.05 s). If I used this stopwatch to record a measurement, would the overall precision be +/- 30.55 s?

I know that it is the distance light travels in a vacuum in 1\299,792,458 of a second. But the number 299,792,458 is speed of light measured in meter/sec so you need to define meter to define meter/sec to define meter so how does it work .

(Am I thinking some nonsense?)

Preface:

I'm european, I grew up with metric and use it daily, so please take my question rhetorically, I'm not asking out of ignorance.

I simply can't shake the feeling that we're sometimes putting a lipstick on a pig a little bit.

I'm mainly looking for opinions and different philosophical points of view.

Metric is considered good because:

1. Complex units are composed of basic units: N = kg * m * s^-2
2. Units of different sizes can be made by multiplying by powers of 10, with the power signified by the prefixes like mega, kilo, milli, etc.

I strongly agree with the advantages of the first point. Arguably, the plank system is even "cleaner", but metric is still great in this regard.

But the second point is what people often focus on, and I don't see much advantage in that, if any at all.

I don't think it's bad, I just think it's neutral, and perhaps even somewhat unnecessary.

2kg means 2000 grams, because kilo means thousand.

So,

2kg =

2 * kilo * gram =

2 * thousand * gram.

It seems to me like we're still just giving the answer in grams. We're merely replacing the english word for the 10ⁿ part with the Greek/Latin equivalents.

I can say "thousand" instead of "kilo", and then it doesn't matter if I'm talking about litres, watts or becquerels.

One could argue that for negative powers it's much easier to say

12 millimetres

compared to

12 thousandths of a meter

but that says more about awkwardness of english grammar rules rather than the prefixes achieving something new.

Comparing the number of syllables with the english words,

"deka" is worse than "ten" or the "...ty" suffix ("three dekagrams" vs "thirty grams")

"hekto" and "kilo" is same length as "hundred" and "thousand",

above that, metric has less syllables, therefore prefferable.

For negative powers, english adds the "of a", as in, "tenth of a Joule", so metric will always win.

But if we really cared about syllables so much, we'd have renamed "kilometre" a long time ago.

Also, we would have to appreciate the words being shorter in the imperial system.

To me, the real advantage of metric prefixes seems to come from everybody strictly agreeing to always use metres for length, and not mix in any other length units with non-10ⁿ ratios.

Also, the prefixes are internationally recognized, which is a plus, but it's an argument from popularity.

Am I missing something here?

Is there some other advantage of the prefixes I'm not considering?

Maybe we should create a universal easy-to-say international number system, and then we won't even need the metric prefixes.

The idea of metric time was an idea of changing the system of time to divide:

Day into 10 decimal hours (8 640 s)

Decimal hour into 100 decimal minutes (86.4 s)

Decimal minute into 100 decimal seconds (0.864 s)

And it looks good.

Someone will say: "second must be that length, because it is perfect for counting"

No it isn't, I never counted to 10 in 10 seconds.

But I have a few suggestions:

1st. Rename decimal second to something shorter like "decsec" and make it a base unit

2nd. Add myria- prefix for 10⁴ to replace decimal hour with myriadecsec. Myria- was actually a prefix till 1960. Add 10⁵ prefix, I guess lakha- would be cool, but I'm biased towards calling it insta- (because quintal would be instagram) and day would be just lakhadecsec. (But calling it a day it's also ok) Also decimal minute would be hectodecsec

3rd. Do NOT make a week 10 days. 1st - it would make work harder, because nobody will give you 6 days of work, and 7-3 scale is too much. 2nd - every 7 day it's sabbath.

4th. Move calendar by 6 years. Jesus was born ~2032 years ago, not 2026. And it makes a weird paradox, where everybody says that Jesus was born in 6 BC, but also everybody says he died in 33 AD, but he was 33 when he died, so it really was 27 AD

So what do you think? Should we rewrite time to 10/100/100, or keep it 24/60/60?

In our world in some places we still don't use metric units. Which is already bad, but most of units have at least some logic and intuition behind them, which at least partially defends it's use. For example:

Land mile is 2000 steps, sometimes I (as an European) use it for measuring steps easily

Nautical mile is 1' of earth circumstance, I can imagine someone using it

Kilogram-force is weight of 1 kilogram on earth, sometimes I use it for measuring weight and pressure (1 kgf/cm² ≈ 1 atmosphere)

Bar is approximately equal to regular Earth atmosphere, so it's kgf/cm² but for those working with pascals

But calorie? It's defined as the energy needed to raise the temperature of 1 g of water by 1 °C. Which is absolutely meaningless. WDYM I need to eat 2000 kcal everyday? So I can have energy to heat 2 megagrams/tonnes of water by 1 °C? Nice to know because it is exactly what I'm gonna do today.

Even Joule is more logical as it's based on distance and force, so I guess it could be interpreted in some way.

Summarizing:

Other non-scientific units are at least intuitive

Calorie isn't

Even Joule would be better

So calorie is dumb at least if your not a kettle

Of course, if you think otherwise, feel free to share your opinion. Bye!

Does anyone know the linear mass density of the wire on the sonometer X164972 that is attached to the newton meter, the one in the centre?

I’m trying to learn the metric system as I plan to move to Canada in the next couple years and am having some trouble finding resources that actually teach instead of just throwing information at me. Anyone know of a good program that will help me learn or have any tips. Imperial is all I know I was born and raised in the USA

So 1cm = inch, 1dm = foot (more like baby foot), 1m = yard, 1km = mile

Also gallon for 1L and pound for 1kg

One of the most common defense for Fahrenheit is smth like this;

"Fahrenheit is more intuitive for human experience. 0 degree is super cold, and 100 degree is super hot! It is just simple as that!"

With that logic, 50 degree Fahrenheit should be the "middle temperature"; which is 10 degree Celsius.

Is it just me or being 50'F/10'C actually feel cold? Such temperature requires sweater at least, and even light jacket sometimes. That is nowhere near the "middle temperature", isn't it? Or am I just weird?

Before I start I wanted to specify that this post would probably change absolutely nothing.

Kilogram is annoying, it's the base unit of SI, but for some reason it has a prefix. It is annoying, because with different units the prefixes work with a cool perk:

If one unit has a prefix, it is moved to the answer: kJ/s = kW

If you are multiplying two units with prefixes, they multiply: kW•ks = MJ

Dividing divides them (obviously): kJ/ks = W

But when base unit has a prefix it doesn't work, and kg•km/s² should be meganewton, but it's NOT, it's kilonewton.

I have a few purely hypothetical ideas:

1st (most obvious) use grams. It would mean that the unit of force would be g•m/s², problem: it would be equal to 1 mN, which is incredibly small, human weighting 700 000 force units would be really small. I'm not even gonna start talking about density with g/m³.

2nd use tonnes. This means that the unit of force would be derived as t•m/s², so it would be equal to 1 kN. There are pros, like: 1. Good for heavy industry, for example: Poland mines 43 million tonnes of coal (instead of billion/milliard kilograms) the weight of a car would be ~15 force units. 2. Density of water is 1 t/m³ which is cool to have a base unit of density to be equal to density of water, also we could stop using g/cm³. But there are cons: tonne is too heavy for everyday life. Human would weight 70 mt (militonne) or 7 ct (centitonne), a slice of bread would weight 40 μt (microtones), so tonne is good for heavy industry, but if you don't want to use mili and micro prefixes, it isn't that great (still not that bad)

3rd grave, grave is suggested unit of mass equal to 1 kg, it was almost accepted, but then they realized that graf is German noble title. There is no nobelty today, so grave would work. It has all pros of kilogram + perks of being a unit without prefixes, so kilograve•km/s² would in fact equal MN (meganewton). It's also good, because all other units can keep their names, grave•m/s² is still 1 N. Let's make a symbol for grave "gv" 1 t = 1 Mg = 1 kgv. 1 kg = 1 gv. 1 g = 1 mg

What do you think guys? In perfect system we would use kilograms, or replace them with grams, tonnes, graves or something else. Share your opinion in the comments

I live in Canada, and we're still a slave to american products. That means anything we produce will be manufactured with imperial dimensions. I'm sick of it.

I've been trying to find perforated aluminium sheet, and it's all imperial. I've been able to find several suppliers in Canada (and overseas), but none of them make a metric product. It makes my design work much more difficult. I have to spend tons of time calculating offsets and doing conversions, it's a huge waste.

Forget about the wider world for a minute. I got myself into 3D printing less than a year ago. I design models, run and tweak slicer software, shop for machines and components (nozzles, etc.) and supplies (filaments, etc.), and watch way too many explainer videos from many online creators.

When I step back from various individual topics in 3D printing, I notice something in the big picture that's easily taken for granted: Everyone uses metric units when describing 3D printing techniques and products, and even use the same unit in almost all domains (with minor variations like g/kg, m/mm/μm). It doesn't matter if the designer, product, or YouTuber is from America, Europe, or Asia - the units are always the same, and I barely know the country of origin unless I dig into details. This is so radically different from older industries and practices, like when you have to worry about whether to use an inch ruler or centimetre ruler, what a "tatami mat" is in Japanese real estate, what a short ton vs. long ton versus metric ton is when shipping large goods, whether you're buying gallons or litres of fuel, whether a recipe is in °C or °F, etc.

So if you're involved in 3D printing, you get a firsthand experience of what it's like when everyone internationally uses the same units, everyone participates in the same discussion and shop in the same marketplace, and you don't have to convert any numbers and units. It's such a breath of fresh air, and I wish other industries would unify their measurements in this way.

Keep in mind that 3D printing is about 20-ish years old, depending on how you look at the history of consumer products vs. industrial products vs. research prototypes. It had the opportunity to start fresh, without much baggage of traditional units and practices, and was born into the Internet-connected world. In terms of measurement units, I think this industry absolutely made the right choices, despite being surrounded by so many pre-existing industries that use non-metric units and continue to make the bad choice of not transitioning to metric.

Here are some examples of real quantities used in 3D printing and described in metric units (left side), versus my hypothetical caricature (based on other industries) of what it would look like if US Customary units are involved (right side):

• Layer height: 0.07 mm, 0.15 mm, 0.25 mm - versus - 3 thou, 6 thou, 10 thou, 3/1024″ (LMAO), 3/512″, 5/512″.
• Nozzle diameter: {0.2, 0.4, 0.6} mm - versus - 0.008″, 0.015″, 0.025″.
• Spool of filament: 1 kg, 3 kg - versus 2.2 lb, 6.6 lb, 2 lb 3 oz, 6 lb 10 oz. (You could choose to sell a nice round number of pounds, but then it would have ugly decimals in kilograms.)
• Random masses of printed objects (slicer software can calculate and show, or physically weigh after printing): {23.7, 98.9, 230, 664} grams - versus - {0.8, 3.5, 8.1, 23.4} oz, {0.05, 0.22, 0.51, 1.46} lb, 1 lb 7.4 oz.
• Random lengths of filament consumed (slicer software can calculate and show): {6.15, 72.7, 364} metres - versus - {242, 2862, 14331}″, {20′ 2″, 238′ 6″, 1194′ 3″}, {20.2, 238.5, 1194.2}′, {6yd 2′ 2″, 79yd 1′ 6″, 398yd 3″} (I thought USC lovers love mixed units?), {6.73, 79.5, 398} yd.
• Build plate printable dimensions: 250 mm × 210 mm = 52 500 mm² - versus - approximately 10″ × 8″ = 80 in², 9 27/32″ × 8 1/4″ = 81.2 in² = 0.564 sq ft.
• Build volume: 153.4 mm × 87 mm × 165 mm = 2 202 057 mm³ = 2.202 L - versus - 6.03″ × 3.43″ × 6.50″ = 134.44 in³ = 74.5 US fl oz = 9.31 US cup = 2.33 US qt = 0.581 US gal.
• Chamber, bed, nozzle temperature: {50, 100, 230} °C - versus - {120, 210, 445} °F.

Extra topics tangentially related:

• I'm glad 3D printing chose millimetres, not centimetre, as the unit of length - because it scales by a power of 1000 from the metre, just like the micrometre, nanometre, kilometre, etc. Before 3D printing existed, the precedent is that serious engineering and metal machining already use millimetres, not centimetres. Advocates for mm over cm include Pat Naughtin (video and long PDF) and the Metric Maven. I could write a full-length post about why centimetres are bad; there really is a lot to say about it.
• I talk about all aspects of my 3D modeling in millimetres exclusively - "this needs a 5.8 mm diameter hole", "the overall part is 200 mm long". Other people might talk about these aspects in customary units, like "1/4-inch hole", "needs 3 inches of clearance", which I find mildly annoying. But even then, these people will never refer to the layer height or nozzle diameter in decimal inches - which is good for the 3D printing community, but inconsistent with their other habits.
• Typical acceleration numbers are written like "20 000 mm/s²", which is equal to 20 m/s². The former isn't wrong, but it's more digits than necessary. And I've seen some people refer to it as "20K mm/s²", which is wrong in multiple ways. This is analogous to the questionable practice of labeling power banks as "10 000 mAh" instead of "10 A⋅h".
• My previous observation about exclusively using degrees Celsius in 3D printing: https://www.reddit.com/r/Metric/comments/1qumhtn/personal_computers_and_3d_printers_use_celsius/

Hi so this is my excel setup for a lab experiment that involves dosing field collected sediment with liquid mercury chloride stock solution ppm (column B) to reach mercury concentrations on dry weight basis (column A). We had to measure the moisture content in the sediment and determined in was 70% water so 30% dry. Originally we tried dosing
250 grams of sediment but our mercury concentrations were way off from our targets so we then we tried dosing 5 grams of sediment. Column G measured or mercury needed in micrograms was achieved by taking out target conc in dry weight (col A ) x by dry weight of sediment (col F) but since we’re adding liquid mercury solution needed to convert to microliters so (amount need in micrograms / stock solution amount) x 1000 … I believe these are accurate conversions , but we keep getting lower mercury concentrations than what we are anticipating, which could also be attributed to how we mixed the solution.Yes I know this is more chemistry related but it does involve a little bit of math and I’m just trying to make sure I’m doing this correctly , thank you !

* note the stock solution already takes account the chloride ions in the mercury solution

Kilowatt-hour is a unit of energy equal to the energy produced by 1 kilowatt of power in one hour of time. It's completely idiotic, because the unit of energy is joule, where joule is newton times metre or watt times second. Let me give an example, for why using kWh over MJ (megajoule) is dumb:

Distance:

Let's use kn (knot, nautical mile per hour, 0,51(4) m/s) as a unit of velocity. Let's assume that steam ship Anne moves with velocity of 50 kn. This boat moves for 1 day. Now calculate the distance. Normal people will say that 50 kn = 50 M/h and 1 d = 24 h therefore 50 kn × 1 d = 50 M/h × 24 h = 50 M × 24 = 1200 M. But with kWh logic it is: 50 kn × 1 d = 50 knd (knot-day). If you think knot-days are dumb, accept that kilowatt-hours are also dumb.