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What is mass?

One of the task during the strongman competition is to lift a stone or concrete ball (weighing 110 - 190 kg) from the ground and place it on the platform in the shortest possible time. Do balls of comparable volume made of Styrofoam have a similar mass?

Matter is everything that surrounds us which has a mass and a specific volume.

The formal definition is:

The kilogram, symbol kg, is the SI unit of massmassmass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015 × 10Indeks górny −34⁻³⁴ when expressed in the unit J⋅s, which is equal to kg⋅mIndeks górny 2²⋅sIndeks górny −1⁻¹, where the metre and the second are defined in terms of c and ΔνIndeks dolny Cs_Cs.

*SI (Système international d'unités) – International System of Units is a system of physical units, such as, for example metre, kilogram, second, and multiples thereof determined using prefixes.

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Zdjęcie przedstawia cylinder o wysokości i średnicy równej 39 mm wykonany ze stopu 90% platyny 10% irydu. Cylinder znajduje się pod dwoma szklanymi kloszami, jednym mniejszym drugim większym. Znajduje się w miejscowości Sèvres na przedmieściach Paryża. Cylinder ten do maja 2019 roku był wzorcem kilograma.

The body with the same mass – depending on the force of gravity and the place of measurement – may have different weight. The gravity on the Moon is lower than on Earth, so the astronaut’s weight is lower on the Moon. The unit of weight (force of gravity) is Newton (N).

What volume means?

Volume determines how much of space is occupied by a given body; the unit of volume is a cubic meter (mIndeks dolny 3₃) in SI

In everyday life, we usually use a smaller unit – litre (1 dmIndeks górny 3³ = 1 litre). Liter is not a unit of the SI system. The methods for determining the volume of a substance depend on its state of matter. Volume of liquid is measured using laboratory glassware with graduation scale. In the laboratory, measuring cylinders and pipettes are used for this purpose, and cubic decimetre (dmIndeks dolny 3₃) is a unit. At home, we can use glasses or spoons. The following are examples of approximate volume conversion rates.

How is the volume of gases determined?

The volume of gases depends on the size of their „packaging” because the gases fill up all of their available space. For example, when drinking water from a bottle, the air takes up the empty space. The empty 1 litre bottle contains a litre of air.

How is the volume of solids with regular shapes determined?

The volume of solids with regular shapes can be calculated based on their dimensions.
The volume of cube is calculated using the formula:
$V=a^3$, and the volume of cuboid – using the formula: $V=a·b·c$

How is the volume of solids with irregular shapes determined?

Volume of solids with irregular shape can be determined by immersing an object in a cylinder filled with water. The volume is a difference between the final volume (after immersing the object) and the initial volume of water in the cylinder.

Meniscus
MeniscusmeniscusMeniscus is the curve (place of adhesion) in the upper surface of a liquid close to the surface of the object – measuring cylinder. There is convex (water) and concave (mercury) meniscus – it depends on the value of adhesive forces between liquid molecules and glassware walls as well as on the intermolecular forces between liquid molecules.

Parallax is the phenomenon of erroneous reading of the measuring instrument. The reason is the wrong angle at which the person is looking. The line of sight passing through the indicating element, e.g. the liquid bar in the measuring cylinder, is directed to the wrong point on the reading scale behind this element. The difference between the actual reading and the correct reading value is called the parallax error.

Summary

• Mass is a measure of the amount of matter determined by means of a weight.

• The kilogram pattern is stored at the International Bureau of Weights and Measures in Sѐvres near Paris.

• The body of the same mass, depending on the strength of gravity and the place of measurement, may have different weights.

• In the SI system, the unit of volume is cubic meter mIndeks dolny 3₃.

• The methods for determining the volume of a substance depend on its physical state.

• The volume of the irregularly shaped solid can be determined by immersing this object in a cylinder with water.

Key words

volume, weight, mass, meniscus, substance

Glossary