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116 votes
Accepted

How do you make more precise instruments while only using less precise instruments?

I work with an old toolmaker who also worked as a metrologist who goes on about this all day. It seems to boil down to exploiting symmetries since the only way you can really check something is ...
DKNguyen's user avatar
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102 votes
Accepted

How do we know the LHC results are robust?

That's a really great question. The 'replication crisis' is that many effects in social sciences (and, although to a lesser extent, other scientific fields) couldn't be reproduced. There are many ...
innisfree's user avatar
  • 15.2k
65 votes

How exactly do you avoid fooling yourself?

There are lots of different strategies that are employed by the scientific community to counteract the kind of behavior Feynman talks about, including: Blind analyses: In many experiments, it is ...
probably_someone's user avatar
62 votes

How do you make more precise instruments while only using less precise instruments?

The more you measure things and add or multiply those measurements, the greater your errors will become. Not necessarily. If the errors in a series of measurements are independent and there is no ...
gandalf61's user avatar
  • 56.5k
46 votes

How seriously can we take the success of the Standard Model when it has so many input parameters?

It is inaccurate to think that all of the standard model of particle physics was determined through experiment. This is far from true. Most of the time, the theoretical predictions of particle physics ...
joseph h's user avatar
  • 29.9k
42 votes

How exactly do you avoid fooling yourself?

My favorite story (which I learned about recently) is about Frank Dunnington and his measurements of electron properties in about 1930. He was measuring the ratio $e/m_e$. Experiments took quite a ...
lesnik's user avatar
  • 4,202
38 votes
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Line of Best Fit with or Without Constant Term

You should almost always include the intercept. Not including the intercept can lead to bias in your estimate of the slope in your model as well as other problems. it is generally a safe practice not ...
Dale's user avatar
  • 103k
34 votes

How do you make more precise instruments while only using less precise instruments?

One thing I haven't seen mentioned is amplification. Amplification: Imagine you have a lever that is 10 cm on one side of the pivot and 1 m on the other. Then any change in position on the short side ...
CookieNinja's user avatar
32 votes

How seriously can we take the success of the Standard Model when it has so many input parameters?

The Standard Model may have many parameters, but it also talks about many things, each typically only involving a very limited number of parameters. For example, the muon lifetime$^\dagger$ $$\tau_\mu=...
J.G.'s user avatar
  • 25k
32 votes

Spinning gyroscope loses weight?

You are substantially overstating the precision of your measurements. The readings changed rapidly so they had to be read by stepping through videos of the experiment. What you mean is that you ...
Dale's user avatar
  • 103k
27 votes

How do you make more precise instruments while only using less precise instruments?

That's a really nice one! I'm not an expert on experiments and measurements but this is how I see it: The ultimate calibration tool is always nature. We pick special phenomena which rely on certain ...
Cream's user avatar
  • 1,618
25 votes
Accepted

Why don't we use absolute error while calculating the product of two uncertain quantities?

It basically comes from calculus (or more generally just the mathematics of change). If you have a quantity that is a product $z=x\cdot y$, then the change in this value based on the change of $x$ and ...
BioPhysicist's user avatar
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23 votes

Is there any advantage in stacking multiple images vs a single long exposure?

Stacking is something that is done all the time in infrared astronomy. This is done because CCD technology doesn't work for wavelengths in the range of roughly 2 to 10 microns, and beyond, so they use ...
Sean E. Lake's user avatar
  • 22.7k
23 votes

Least squares fit versus averaging

That's a good question. The answer depends on how the data is collected. We will posit two simple models and furnish the best unbiased estimator for each model via the Gauss Markov theorem. We will ...
user551504's user avatar
22 votes
Accepted

How do scientists determine when to disregard a model that has a higher correlation to data than another model?

For any set of data points, you can comprise a 100% interpolated and fitted curve using a sum of sloped lines all multiplied by their respective Heaviside step functions to form a zig-zag shaped curve....
anna v's user avatar
  • 234k
22 votes

Least squares fit versus averaging

Here is the quantitative (simulation) approach @Dr. Momo was mentioning: we can simulate some points for $x_i$ and $F_i$, give them some Gaussian errors, estimate $k$ with the two approaches and see ...
Jacopo Tissino's user avatar
21 votes

How do you make more precise instruments while only using less precise instruments?

Measurement errors can accumulate, yes. But we are not talking about measurements here, we are talking about processes and tooling. That's another deal. If you fling off a piece of flint from a ...
Steeven's user avatar
  • 51.5k
21 votes

Line of Best Fit with or Without Constant Term

I cannot improve on Dale's answer, but speaking as an (ex) experimental scientist I strongly recommend you allow a non-zero intercept as it can be useful indication that you have systematic errors ...
John Rennie's user avatar
21 votes
Accepted

Observation of the effect of gravity on the motion of antimatter

Usually these error estimates are "one sigma" error bars, which is roughly the same thing as a 68% confidence limit. If you have an ensemble of data with $1\sigma$ error bars, you expect ...
rob's user avatar
  • 91.5k
20 votes

Easy to perform quantitative experiments at home

The simple pendulum experiment is very simple to perform, from which a lot of conclusions can be drawn. An object like a ball, like an apple can be used as a weight at the bottom, and a string can be ...
Sumant's user avatar
  • 687
18 votes
Accepted

Least squares fit versus averaging

As in all things statistical, it completely depends on your assumptions. Why averages are useful: If you have a variable x which you can sample, and it comes from a normal distribution with some mean $...
Alwin's user avatar
  • 5,060
17 votes
Accepted

When to average in the lab for indirect measurements?

Averaging destroys information. Do it as late as is practical in your analysis. A commenter points out that, if you are making many position/velocity measurements of the same object as it moves once, ...
rob's user avatar
  • 91.5k
17 votes

How do you make more precise instruments while only using less precise instruments?

The way I understand it, errors only accumulate. That is not always the case. Human ingenuity found and systematically selected processes which improved a particular quality. Two examples: You can ...
g.kertesz's user avatar
  • 958
16 votes

Is there any advantage in stacking multiple images vs a single long exposure?

The voice of bitter experience, here, to tell you about a problem that a properly working observatory shouldn't have to worry about. But I did the time I was working on a "serious" astronomy project. ...
dmckee --- ex-moderator kitten's user avatar
16 votes

How exactly do you avoid fooling yourself?

What Feynman is talking about is not particular to physicists, its particular to human nature and it is called "confirmation bias" Confirmation bias is the tendency to search for, interpret, favor, ...
anna v's user avatar
  • 234k
16 votes

How seriously can we take the success of the Standard Model when it has so many input parameters?

The LHC has produced 2,852 publication as of today: September 24, 2021. Let's say each publication has 5 plots. Each plot has 50 points. We'll round that up to 1,000,000 data points, along with a ...
JEB's user avatar
  • 35.4k
15 votes
Accepted

Is there any advantage in stacking multiple images vs a single long exposure?

If your exposures are short enough (a fraction of a second), you can even combat turbulence in the atmosphere. The trick is to do very many short images then pick the ones where a (bright) point ...
ProfRob's user avatar
  • 133k
15 votes

How do you make more precise instruments while only using less precise instruments?

I expect that worm drives are part of the story. For every rotation of the driven axis the driving axis goes through multiple rotations. I expect that it is mechanically possible to capitalize on that ...
Cleonis's user avatar
  • 21.4k
14 votes

How do we know the LHC results are robust?

In addition to innisfree's excellent list, there's another fundamental difference between modern physics experiments and human-based experiments: While the latter tend to be exploratory, physics ...
chrylis -cautiouslyoptimistic-'s user avatar

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