In response to the usual question "How much does a liter of water weigh?" most people will offer to look in the handbook, or simply say, "One kilogram." Indeed, at a temperature of 400C and under normal atmospheric pressure, the weight of one liter
distilled, that is, devoid of any impurities, water is exactly 1 kg. And who can unequivocally answer the questions "How much does a liter of water from a s alty spring weigh?" or "Which water is heavier - hot or cold?"
In order not to get into trouble, you need to familiarize yourself with some elementary laws of physics. For more specifics, it should immediately be noted that in our article we will not talk about the weight of water, but about its mass. The difference between these terms is that mass is a fundamental indicator of the amount of matter, and it is measured in kilograms, and weight is a value that shows how much force a body with a certain mass presses on the surface; its unit is Newton.
To answer the question of how much 1 liter of water weighs, first let's see what indicators make up body weight. From the course of physicswe know that mass is a product
density of matter on the free fall acceleration coefficient, which is approximately the same on the entire surface of our planet and is equal to 9.81 kg/m2. The fluctuations of these two quantities give us the difference in the mass of the same substance under different conditions.
First, let's talk about the density of the liquid. As mentioned above, the density of pure water under normal conditions is 1000 g/m3. If impurities, such as s alt, are added to it, then the density will increase, and the water will become heavier. As for the dependence of the mass of an object on temperature, the whole point here is in the property of substances to expand when heated. This means that the distance between the molecules becomes larger, and their total number per unit volume decreases, therefore, the substance becomes lighter. However, water has a unique property - it expands not only when heated, but also when cooled (it is because of this that water pipes burst in winter). Water has the greatest density at the freezing temperature, with the slightest deviations of the thermal scale, it becomes lighter. How much a liter of water weighs at different temperatures, if you wish, you can look in the reference book.
Atmospheric pressure does not affect fluid mass fluctuations as much as
temperature, and the result of its action is the opposite of high temperatures. At high pressure, the distance between the molecules decreases, therefore, the same volume will includemore substance. As a result, there is an increase in mass. This can be easily seen in practice, if we weigh a cylinder of compressed air and the same cylinder with air under normal pressure.
By the way, do you know how much a liter of water weighs at the pole? 0.5 percent more than at the equator. This phenomenon is due to the rotation of the Earth around its axis. Because of it, centrifugal acceleration increases as you approach the equator and, therefore, the acceleration of gravity increases.
Thinking like this, you can calculate how much a liter of any liquid weighs, and how this indicator will change depending on environmental conditions.
