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More to the point: Theories don't become laws, theories generate laws; testing those laws is a test of the theory. Laws are mathematical equations which relate

by cbd1984 12y ago

More to the point: Theories don't become laws, theories generate laws; testing those laws is a test of the theory. Laws are mathematical equations which relate observable quantities such that we get quantitative predictions. The Ideal Gas Law, PV = nRT, is one example: It relates Pressure (P), Volume (V), number of moles of gas (n), a physical constant (R), and Temperature (T) such that we can predict the values of certain traits, or the relationships between traits, given some known or hypothesized values for the other traits. The theory it's part of is the one that says gasses are made out of tiny particles called atoms or molecules, which fly around freely and bounce off each other and solid surfaces with a speed proportional to their temperature. Every time the Ideal Gas Law makes a good prediction, that theory gets validated.

scott_s 12y ago
I'm going to have to disagree. There's no meaningful distinction between "laws" and "theories". One famous consequence of the theory of special relativity is the mass-energy equation - but we do not call E = mc^2 a "law". We just say it's a part of the theory of special relativity. That, however, does not mean the theory of relativity and E = mc^2 has a lower status than Newton's law of universal gravitation and F = (G m1 m2 )/r. That we call one a "theory" and the other a "law" is just an accident of speech. It's not even a difference of semantics - in this context, "law" and "theory" have the same meaning. We just continue to say "law" for some things for historical reasons.
- Avshalom 12y ago
  We call it the law of conservation of mass. Or well its a limit case, but yeah we absolutely do call it a law. Theory is the explanation, law is the model.
  - scott_s 12y ago
    The distinction you propose is demonstrably not true in modern theories. (Where "modern" means a bit over 100 years old.) We call such things a law, but there is no difference between a theory and a law. Such "laws" just predate our current philosophy of science, and we continue using names like "the Ideal Gas Law" because we always have. If someone came up with an equivalent thing now, we would not use the term "law" - which we can observe with physics from the 20th century.
- cbd1984 12y ago
  Perhaps you're right. Mark this one down to schools teaching outdated things as fact, I suppose. Still, my idea is better than the "hypotheses become theories, which become laws" nonsense, which is still taught at the elementary school level.

by cbd1984 12y ago

scott_s 12y ago

I'm going to have to disagree. There's no meaningful distinction between "laws" and "theories". One famous consequence of the theory of special relativity is the mass-energy equation - but we do not call E = mc^2 a "law". We just say it's a part of the theory of special relativity. That, however, does not mean the theory of relativity and E = mc^2 has a lower status than Newton's law of universal gravitation and F = (G m1 m2 )/r. That we call one a "theory" and the other a "law" is just an accident of speech. It's not even a difference of semantics - in this context, "law" and "theory" have the same meaning. We just continue to say "law" for some things for historical reasons.

Avshalom 12y ago
We call it the law of conservation of mass. Or well its a limit case, but yeah we absolutely do call it a law. Theory is the explanation, law is the model.
- scott_s 12y ago
  The distinction you propose is demonstrably not true in modern theories. (Where "modern" means a bit over 100 years old.) We call such things a law, but there is no difference between a theory and a law. Such "laws" just predate our current philosophy of science, and we continue using names like "the Ideal Gas Law" because we always have. If someone came up with an equivalent thing now, we would not use the term "law" - which we can observe with physics from the 20th century.
cbd1984 12y ago
Perhaps you're right. Mark this one down to schools teaching outdated things as fact, I suppose. Still, my idea is better than the "hypotheses become theories, which become laws" nonsense, which is still taught at the elementary school level.