### Haircheck. Check!

Unfortunately

**i**do not**own a**mirror.*This*is a standart

**hairchecking**procedure.

Similarities. Both of them are statements based on observations, that seem to be true, but have not been proved or disproved jet.

Differences. As explained in G.Pólya and L.Bowden book "Mathematical methods in science", difference is in level of credibility that explanation is based on. Hypothesis is testable, and explanation is based on accepted grounds. Conjecture is proposition based on inconclusive grounds, and sometimes can not be fully tested.

Another difference is that conjectures, unlike hypothesis, are used in math. Hypothesis usualy are used elsewhere. If conjecture is proven, it becomes a theorem. Still, the border between two terms remains blurry, and terms sometimes are used as synonyms. For example in math there is a conjecture called 'Riemann hypothesis', which correctly should be called ‘Riemann conjecture’.

Differences. As explained in G.Pólya and L.Bowden book "Mathematical methods in science", difference is in level of credibility that explanation is based on. Hypothesis is testable, and explanation is based on accepted grounds. Conjecture is proposition based on inconclusive grounds, and sometimes can not be fully tested.

Another difference is that conjectures, unlike hypothesis, are used in math. Hypothesis usualy are used elsewhere. If conjecture is proven, it becomes a theorem. Still, the border between two terms remains blurry, and terms sometimes are used as synonyms. For example in math there is a conjecture called 'Riemann hypothesis', which correctly should be called ‘Riemann conjecture’.

How many water molecules are in a glass of water?

This glass is filled with 200 ml water. That is 0,2 l of water. First, to get started, we need to convert volume to mass. Since 1l water equals 1kg water, then our 200 ml glass is filled with 0.2 kg water. In school chemistry probably in 8th grade there was a term**Mole.** Mole is a unit and it measures number of molecules. One mole has 6.0221415×1023 molecules in it. And another term is **molar mass.** The molar mass of an element is the atomic weight in grams per mole. In other words molar mass states - how much does one mole of particular substance weight.

The molar mass for distilled water is 18 g/mol or converting to kg, it is 0,018 kg / mol.

So, now lets do some calculations. First, let's calculate - how many moles of water there are in the glass.

*Moles = mass / molar mass = 0,2 kg / (0,018 kg/mol) = 11.11 moles*

And then, let's calculate how many molecules there are in the 11.11 moles Number of molecules = number of mols * molecules in o…

This glass is filled with 200 ml water. That is 0,2 l of water. First, to get started, we need to convert volume to mass. Since 1l water equals 1kg water, then our 200 ml glass is filled with 0.2 kg water. In school chemistry probably in 8th grade there was a term

The molar mass for distilled water is 18 g/mol or converting to kg, it is 0,018 kg / mol.

So, now lets do some calculations. First, let's calculate - how many moles of water there are in the glass.

Some people like to draw on paper while talking to phone. Isn't it strange? Why do they like to do such a thing, I asked my self. In my opinion, there are two reasons for that.

**First**, having pen or pencil in hand makes them feel more relaxed. Because usually when speaking to phone talker is receiving important information, and it might be necessary to put down some notes. May it be addresses, dates or hard-to-remember numbers. Also, it is verbal information talker receives, and as soon as words are said, they disappear. Adding down notes allows them more effectively follow conversations.

**Second**, one needs to focus attention on information that is received by ears and ears only. All other senses, meanwhile, must be ignored. And to avoid information that is presented by eyes and usually is unrelated to what conversation companion says, talker draws something very unrelated to the paper and looks at his work without a lot of interest. The received information must to be filtered, too,…

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