Today I saw a Jian you introduce quality 、 The article of energy relation formula , I just want to come “ 8、 ... and ” Let's talk about this .
People often say quality 、 Texture , Quality is quality 、 There is . Everything has quality , In the international system of units , The unit of mass is kg. And what is energy ？ Energy is neither visible nor palpable , We don't seem to quite understand the nature of it , But it does exist , The unit of energy is J.
So is mass related to energy ？ It doesn't seem to matter .
In classical physics , Mass has nothing to do with energy , Daily life experience also tells us that this is true . Strictly speaking , Even if there is a relationship, it can't be proved by daily facts .
And in the field of relativity , energy E And quality m It's inseparable and closely connected , A certain mass corresponds to a certain energy , Where there is mass, there is energy , vice versa . Energy is a form of mass , Energy and mass are expressed in Einstein's mass energy relation E=mc² Connect , This quantification can directly reflect the relationship between energy and mass . How to understand , Two examples can be cited for qualitative analysis .
The coast is sunny and hot , The sand on the beach is hot , If there is no sunshade , Staying on the beach a little longer is bound to peel off a layer of skin . Every minute the sun radiates energy to the ground with light and heat . Then maybe someone will ask , Evidence quality - It's a relationship , The mass of the sun will continue to decrease , Will we see the solar system no longer exist one day ？ It's thousands of years since there are written records , Qualitatively , According to this formula, the reduced mass of the sun makes the sun now in its prime , So don't worry about it .
Maybe someone will ask , Can you give me a more practical example ？
A thermos bottle containing 2.5 kg 100℃ Hot water , Suppose the next day the temperature becomes 20℃, By quality - The energy relation , The loss of heat energy corresponds to the loss of a certain mass , Why don't we feel its loss ？ According to the quality - It can be calculated by the formula , The loss of energy corresponds to a mass loss of about 100 billionths of the original mass （10⁻¹² One of the powers ）, No scale in the world can weigh this mass , So we can't feel it , But in theory there is .
This formula is mainly used to calculate the mass defect in nuclear reactions and the energy of high energy particles . so to speak , There is no quality - There is no energy relation “ Mushroom cloud ”, There is no atomic bomb or hydrogen bomb , There's no nuclear reactor , There is no nuclear energy for the benefit of mankind today .
A woman in red came up on the beach , Feel her professional photographer “ Air field ” Did you? ？ Joking . We often say that someone has “ Air field ”, Although this is a more artistic word , But physically “ Air field ” It does correspond to a certain “ Energy field ”, Because it exists in a special material form , So people around can feel it .