Name: 昆蟲如何在水上行走？| 昆蟲在水面上行走 (How do some Insects Walk on Water? | #aumsum)
Uploaded: 2021-01-14T08:09:19.000Z
Duration: 26 min 14 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。

Each water molecule is attracted by other molecules around it in all directions.

But since the molecules at the surface have no molecules above them.

These inward forces of attraction create surface tension.

Thus, making the surface act like a stretched membrane.

Now, the weight of insects like water strider and fishing spider is very less.

So, the force that the insects legs exert on the stretched water surface is lesser.

Also, as their legs are spread wide apart.

Their weight gets further distributed among all the legs.

And just create dimples on the stretched water membrane.

Why is nuclear fusion not used to generate electricity?

You really want to know the answer to this, right?

Before answering the question, let us understand what is meant by nuclear fusion.

When two lighter nuclei combine to form a heavy nucleus.

Where does this nuclear fusion take place?

You think that it takes place in a laboratory?

The nuclei of two hydrogen atoms join together to form a heavy nucleus of helium.

With the release of a large amount of energy.

It does not reach us through power lines.

The energy released after nuclear fusion reaches us in the form of sunlight.

But we are already producing electricity with the help of nuclear fission.

For this, you need to first understand difference between nuclear fusion and nuclear fission.

As we already know, nuclear fusion is the fusion of two lighter nuclei.

The exact opposite process happens in nuclear fission.

Here, a heavier nucleus splits into two lighter nuclei, releasing a large amount of energy.

This process of fission is used in nuclear power plants.

Where a heavy nucleus of uranium is split into lighter nuclei.

The energy that is released in this is used to generate electricity.

However, there is a major disadvantage of nuclear fission.

The major disadvantage is that uranium is a radioactive element.

When uranium undergoes fission, it generates radioactive waste along with energy.

This radioactive waste is very harmful for most lifeforms and the environment.

Hence, we need to find a clean and safe source of energy to generate electricity.

Then why are we not harnessing the energy of nuclear fusion to produce electricity?

This is because, for nuclear fusion, two conditions are required.

They are high pressure and high temperature.

Only when these conditions are met, can the two nuclei travel at very high speeds.

On earth, it is extremely difficult to create such high pressure and temperature.

Even if we are somehow able to create these conditions.

The question is how will we control them?

As there are many questions unanswered and unsolved.

We have not yet succeeded in using nuclear fusion in the production of electricity.

Why is a laboratory thermometer not used to check body temperature?

Why don't you check your body temperature using a thermometer?

Please do not use a laboratory thermometer.

You will not be able to get the correct reading.

A clinical thermometer is different from a laboratory thermometer.

When we check our body temperature, the kink present in it prevents the mercury.

From falling back down, thus helping the thermometer to hold the temperature recorded by it.

Now, in a laboratory thermometer, this kink is absent.

This is because a laboratory thermometer is meant to measures immediate temperature.

Hence, after recording our body temperature, until we check it, the mercury will fall.

Looks like you are searching for a treasure hidden in a sunken ship.

It will emit ultrasounds and help you locate the ship.