Name: 密度 - 為什麼油會浮在水面上？| 密度 - 為什麼油會浮在水面上？ (Density - Why does oil float on water? | #aumsum)
Uploaded: 2021-01-14T08:10:07.000Z
Duration: 4 min 38 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Did you realize that a large log of wood floated on water but a comparatively smaller piece of rock sank?

It is the measure of the mass of an object per unit volume.

In the first case, the log of wood floats on water because it has less density than water.

This means that the amount of mass present in unit volume of wood.

Is less than the amount of mass present in unit volume of water.

However, in the second case, the piece of rock sinks because it has more density than water.

This means that the amount of mass present in unit volume of rock.

Is more than the amount of mass present in unit volume of water.

Do you know why the helium filled balloon is rising up in the air?

The balloon consists of helium gas which has less density than the surrounding air, hence it rises up.

Are you assuming that this is because of density?

However, there is another reason due to which oil floats on water.

The reason is that both oil and water are immiscible liquids.

They do not mix with each other even if we shake them.

They separate out into two layers when kept undisturbed for sometime.

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密度 - 為什麼油會浮在水面上？| 密度 - 為什麼油會浮在水面上？ (Density - Why does oil float on water? | #aumsum)

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