(ORDO NEWS) — What weighs more: a kilogram of cotton wool or a kilogram of iron? This classic trick question has a true scientific answer.
Of course, based on logic, the answer is obvious – the same. But not everything is so simple
In a 2007 study, participants were blindfolded and asked to hold up two tightly closed boxes of the same size, shape, and mass.
In one box was a kilogram of iron, and in the other – a kilogram of cotton wool. Participants were not informed about what exactly was in each box.
Surprisingly, more often than not, participants reported that the iron box was heavier.
Consider the situation in more detail
If this experiment is carried out in a vacuum (that is, under ideal conditions), then, of course, the scales will show the same weight.
However, if weighing is done without laboratory conditions (that is, in the environment), then the weight will be determined by the resultant of two forces: gravity (downward) and Archimedes’ force (upward).
Using this formula, you can independently see the difference in weight:
∆F = g ∙ ρ(air) ∙ (ρ(iron) – ρ(wool)) / (ρ(iron) ∙ ρ(wool))
The smaller the difference in density between two bodies, the smaller their difference in weight will be.
Drawing a conclusion based on the above reasoning, scientists conducted a series of studies and calculations that showed that in the environment, the weight of cotton wool is about 0.4 Newtons less than the weight of iron.
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.