# Stillness of Systems: Physics Laws & Double-Slit Experiment

• StevieTNZ
In summary: The Math for the double slit assumes infinitely thin perfect absorbers with perfect boundaries and interference free paths.
StevieTNZ
Hi there,

I'm not sure if I read somewhere - but if we see a system (macroscopic usually) and it looks still, is it actually not still? Is there a universal equation that governs how 'still' an object is?

In the double-slit experiment, if we have the slits not being still, because we're calculating the paths possible for the system to reach point B as if the slits are in a certain position - they're 'moving' - can we safely ignore any stillness issues in any Physics equation without affecting the accuracy of the Physics equations?

This question dates back quite a while, but am interested in knowing the answer.

Perhaps have a think about the implications of the Uncertainty principle. Prevents you knowing both the position and momentum at the same time. If the momentum is known (for example velocity = 0) then the position is unknown.

http://en.wikipedia.org/wiki/Uncertainty_principle

I'm not sure what the OP means by "safely ignore". Clearly this is a small scale effect that can be ignored in many situations.

The math for the double slit assumes infinitely thin perfect absorbers with perfect boundaries and interference free paths. To the extent that is not true, the results are distorted. The inherent vibration or uncertainty of the molecules at the boundaries and the resulting "non-ideal" interaction with the particle could be modeled. (but not by me)

So, stillness is but one of many factors that can effect experiments. I don't know of any universal treatment of stillness since it could be caused by uncertainty, vibration due to air currents, gravitational effects due to anything, or whatever.

meBigGuy said:
The math for the double slit assumes infinitely thin perfect absorbers with perfect boundaries and interference free paths.

What do you mean by thin perfect absorbers with perfect boundaries?

What do you mean by what do you mean by? (lol)

I think I know what you are asking, but I'm not sure how far I can take it. I'm just saying that the simplistic math assumes the slits and barriers are ideal. There is no reflection from internal surfaces of a thick barrier, that the boundaries are not jagged, and when the barrier is contacted it results in perfect absorbtion (and none if not contacted). In determining the area of the slit there are no angle of approach issues caused by barrier thickness. I think I should have added that the particle is dimensionless. After all, the path integral assumes the particle takes all possible paths and a thick barrier has effects on the possible paths.

## 1. What is the Stillness of Systems?

The Stillness of Systems refers to the concept in physics that states that objects in motion will remain in motion unless acted upon by an external force. This is known as Newton's First Law of Motion.

## 2. What are the Physics Laws?

The Physics Laws, also known as the Laws of Motion, were developed by Sir Isaac Newton in the 17th century. They consist of three laws that describe the relationship between an object's motion and the forces acting upon it.

## 3. What is the Double-Slit Experiment?

The Double-Slit Experiment is a famous physics experiment that demonstrated the wave-particle duality of light. It involves shining a beam of light through two closely spaced slits and observing the resulting interference pattern on a screen.

## 4. How does the Double-Slit Experiment relate to the Stillness of Systems?

The Double-Slit Experiment demonstrates the principle of superposition, which states that a system can exist in multiple states at the same time. This relates to the Stillness of Systems as it shows that even at the quantum level, particles can have both wave-like and particle-like properties, suggesting that they are in a state of stillness until acted upon.

## 5. Why is the Stillness of Systems important in physics?

The Stillness of Systems is important in physics because it helps us understand the behavior of objects in motion and how they interact with external forces. It also forms the basis for many other principles and laws in physics, such as inertia and conservation of energy.

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