ScienceIsSexy420 t1_j2al1m6 wrote on December 30, 2022 at 9:05 PM

Reply to comment by ThenaCykez in ELI5: 1.5 liters of softdrink (coca cola) 1.5 kg as well? by kz21n

I want to expand on this. 1.5L of water weighs 1.5kg by definition. The original definition of the mL was the cubic volume of 1g of pure water at 20°C. So it's is not a coincidence that these numbers are the same, or that the density of pure water is 1.0000, it is so BY DEFINITION.

mjb2012 t1_j2ao3j8 wrote on December 30, 2022 at 9:25 PM

For the benefit of the OP, slightly more ELI5: “by definition” here means that the people who invented the kilogram intentionally said that a kilogram is whatever 1 litre of distilled water weighs (or rather, its mass) at sea level. Basically. So yes, the weight of the soda bottle in kg must be pretty close to it’s volume in litres, assuming it’s filled with mostly water and assuming you’re on the surface of the earth.