Exploring the Nature of Physics: Matter, Energy & Beyond

[LightningInAJar]

Summary:: What does physics study?

Other than matter/antimatter and energy what does physics study? And in what ways are matter and energy similar? Are there additional substances that physics measures?

 

[hutchphd]

Physics was once known as Natural Philosophy.
It is an attempt to use our remarkable brains to discern order in the bewildering world into which we are born. It is the most fruitful of all human enterprise...

 

[hmmm27]

Actually, a decent read.

 

[LightningInAJar]

Actually, a decent read.

So it studies "forces" as well? Anything else along the lines of substance that is studied than just forces that interact with it? Anything that is neither matter or energy?

 

[PeroK]

So it studies "forces" as well? Anything else along the lines of substance that is studied than just forces that interact with it? Anything that is neither matter or energy?

 

[DennisN]

And in what ways are matter and energy similar? Are there additional substances that physics measures?

Matter (more specifically, mass) and energy are related in e.g. this famous equation (the first one on that page), which is a special short version of a longer one further down that page (the third one on that page).

Energy is not a substance on its own. Energy is a quantity that can be measured.
And energy is a property of something, for instance:

The kinetic energy of an object
The potential energy of a system
The energy of/in a field

Also, energy is a quantity that is conserved (see Conservation Laws).
Matter, more specifically, mass, does not obey such a strict conservation law.
Mass is generally conserved, but there are processes in which particles that have mass get "transformed" into particles that have no mass (one example here).

 

[weirdoguy]

Matter (more specifically, mass)

Matter is not a synonym of mass. Matter is a "thing", and mass is a property of that thing.

 

[jbriggs444]

Physics covers the basics. The simple stuff. Mass, velocity, momentum, energy, force, temperature, heat, entropy, electricity, magnetism, the weak interaction, radioactivity, the strong interaction, gravity and relativity.

Then you get chemistry which covers the detailed consequences of electromagnetism and the weak interaction.

Then you get biology which covers the detailed consequences of the enormous suite of intricate chemical reactions that we call "life".

Then you get sociology, economics, politics, psychology and hair styling which cover the enormous suite of interactions of living entities with one another.

 

[docnet]

Are there additional substances that physics measures?

I like to dream that one day I will explain to my unborn kids "why time only moves in one way?" without resorting to philosophy. The mystery of time could eventually be addressed by physics if humans live long enough. At least, it's my hope.

 

[DennisN]

Physics covers the basics. The simple stuff.
[...]
Then you get chemistry...
[...]
Then you get biology...
[...]
Then you get sociology, economics, politics, psychology and hair styling...

My simplified version :

Physics: "Sticks and stones". Quite predictable.
Chemistry: Collections of "sticks and stones". Relatively predictable.
Biology: Large, complex collections of organic compounds. Quite unpredictable on a large scale.
Sociology, Economics, Politics, Psychology and Hair Styling: Voodoo (not meant in a demeaning way). The models sometimes work, sometimes don't.

 

[Vanadium 50]

If it's green, it's biology. If it stinks, it's chemistry. If it doesn't work, it's physics.

 

[Vanadium 50]

And if you have to call it a science ("Political science", "library science") it probable isn't one.

 

[jtbell]

If it's green, it's biology. If it stinks, it's chemistry. If it doesn't work, it's physics.

The version I learned was "If it's dead, it's biology..."

 

[russ_watters]

If it's green, it's biology. If it stinks, it's chemistry. If it doesn't work, it's physics.

If it does work, it's engineering.

 

[BillTre]

The version I learned was "If it's dead, it's biology..."

I had a professor once who liked to say that biology is the study of death since most experiments end up dead (in order to be analyzed).