Thoughts, Epiphanies, Insights, & Quotables

nicsflyingcircus

My scale has both an ml and ml (milk) setting.

PAV8888

Yes. But the scale lies ;-)

It only has one real setting (grams) while telling you it has two by just showing the same value as either ml or g.

That said… apparently the world has moved on from when I was in grade school where they lied to me and had me convinced to this day that 1g of water at 4C / 39.2F is 1mL and that a meter (rod) is sitting in a display case in Paris for each and everyone of us to show up and compare it to our pocket tape measure! Reality appears to be more messy! :)

1 m = the metre is apparently now defined as the distance that light travels in vacuum in 1 / 299,792,458 of a second — my poor rod has been retired!

And volume is totally derived!
1 m³ = a cube 1 m on a side.
1 L = 1 litre is defined as a 0.001 m³
1mL = 1 mililitre = 0.001 L
which makes it a cube that is 1cm x 1cm x 1cm
So by definition, 1 mL = 1 cm³ in volume.

And the mass (weight) of 1ml of water = density of water (at the temperature) x 1mL.

Since density of water depends on temperature (plus small effects from pressure and water isotopes in the mix), we can loosely assume using the OLD definition that they sold me on, that at about ~4 °C, where water's density is very close to 1g/mL, it will be 1g.

But, in actual fact:
Temperature (°C) | Density (g/mL) | Mass of 1 mL (g)

0 °C | 0.99987 | 0.99987 g
4 °C | 1.00000* | 1.00000 g
10 °C | 0.99973 | 0.99973 g
20 °C | 0.99821 | 0.99821 g
25 °C | 0.99704 | 0.99704 g
40 °C | 0.99224 | 0.99224 g
60 °C | 0.98320 | 0.98320 g
80 °C | 0.97180 | 0.97180 g
100 °C | 0.95840 | 0.95840 g

Values in the table are (apparently) standard reference values for pure (air-saturated or air-free depending on table) water at ~1 atm

Around 1795 the liter was linked to 1 kg of water (at its temperature of maximum density), so people expected 1 L ≈ 1 kg.

• Small experimental differences and the difficulty of reproducing exact conditions caused a tiny mismatch between “1 L = 1 kg of water” and the geometric cube definition.

In the 20th century the liter was fixed as exactly 1 cubic decimeter (1 L = 1 dm³ = 0.001 m³) to avoid those experimental problems; the water-mass relation remains only an approximation that depends on temperature.

Item Density (g/mL) Notes

Cotton candy 0.002–0.005 Basically spun sugar air
Popped popcorn 0.05–0.15 Very low density popped starch
Canned whipped cream 0.30–0.40 Mostly air, propellant expands it
Non-dairy whipped topping (thawed) 0.35–0.45 Oil-based plus air
Freshly whipped dairy cream 0.45–0.55 Doubles in volume after whipping
Cheap “airy” ice cream 0.55–0.65 High overrun, more air
Premium ice cream 0.85–0.90 Low overrun, more solids/fat
Butter (soft) 0.90–0.94 High fat content, low water
Olive oil 0.91–0.93 Less dense than water, will float
Canola oil 0.92–0.93 Similar to olive oil, will float on water
Skim milk (4 °C) 1.033 Higher density from dissolved solids, no fat
2% milk (4 °C) 1.031 Slightly less dense than skim milk
Homogenized whole milk (4 °C) 1.030 Lower density from higher fat content
Water (20 °C) 0.99821 Standard density at 20 °C, 1 atm
Cream cheese 1.05–1.10 Solid dairy plus water
Peanut butter 1.10–1.18 Fat and solids packed densely
Sweetened condensed milk 1.28–1.33 Reduced water, high sugar
Maple syrup 1.33 Dense sugar solution
Corn syrup 1.36–1.40 Glucose syrup, high solids
Honey 1.42 Mostly sugars, low water content
Molasses 1.40–1.45 Very high dissolved solids

So 140g to 145g of molasses is 100ml. And 30g to 40g of canned whipped cream is also 100ml. And the poor scale has no way of figuring this out!