The Slinky Drop Experiment Analysed

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In summary, "The Slinky Drop Experiment Analysed" explores the physics behind the behavior of a Slinky when dropped from a height. The analysis highlights how gravity affects the Slinky’s motion, emphasizing the differences between the top and bottom sections during the fall. It discusses the role of tension and the resulting wave propagation through the Slinky, illustrating key concepts such as potential and kinetic energy. The experiment serves as a practical demonstration of fundamental physics principles, including the effects of inertia and the speed of wave transmission in elastic materials.
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Orodruin
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Figure 1: A slinky, the subject of the slinky drop experiment. Attribution: Roger McLassus. CC BY-SA
The slinky drop is a rather simple experiment. In its most basic form, it requires only a popular toy for children, a stable hand, and a keen eye. For a better view, using a modern smartphone to capture a video of the experiment also helps to capture the falling slinky. Apart from the commonly quoted result, Insight will discuss the evolution of the slinky shape during the drop using only high-school physics: mechanical equilibrium and the conservation of momentum.

What is The Slinky Drop Experiment?
The slinky drop experiment is exactly what it sounds like:

Support a slinky at one of its ends. Let the rest of it hang freely under...

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Oh you beat me to it! It seems that you finally used my suggestion of using the displacement field! I have a similar solution that I might share later.
 
  • #3
pines-demon said:
Oh you beat me to it! It seems that you finally used my suggestion of using the displacement field! I have a similar solution that I might share later.
No, the displacement field is still the dependent variable. The slinky fraction ##s## is the independent material variable. This is the way I did it from the beginning.

The only addition is a non-zero rest length of the slinky. Otherwise the analysis is the same as my post #5 of that thread, just a bit more polished.
 
  • #4
Orodruin said:
The only addition is a non-zero rest length of the slinky.
I was talking about that.
Orodruin said:
Otherwise the analysis is the same as my post #5 of that thread, just a bit more polished.
Thanks for the clarification. Anyway, great article!
 
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FAQ: The Slinky Drop Experiment Analysed

What is the Slinky Drop Experiment?

The Slinky Drop Experiment involves holding a Slinky toy by its top end and letting it hang vertically, then releasing it. The experiment demonstrates the principles of tension, gravity, and wave propagation as the Slinky falls and collapses in a counterintuitive manner.

Why does the bottom of the Slinky remain stationary when the top is released?

When the top of the Slinky is released, the tension in the coils above the bottom part supports the bottom part momentarily. This results in the bottom part staying stationary until the wave of compression travels down the Slinky, causing it to collapse and fall.

What forces act on the Slinky during the drop?

During the drop, the Slinky experiences gravitational force pulling it downward and tension forces within the coils. Initially, the tension counteracts gravity at the bottom, but as the Slinky collapses, the distribution of these forces changes dynamically.

How does the Slinky Drop Experiment illustrate principles of physics?

The experiment illustrates principles such as tension, gravity, and wave propagation. It shows how tension within an object can temporarily counteract gravity, and how waves of motion travel through a medium, in this case, the coils of the Slinky.

Can the Slinky Drop Experiment be modeled mathematically?

Yes, the Slinky Drop Experiment can be modeled using differential equations that account for the forces of tension and gravity. These equations describe how the wave of compression travels through the Slinky and how the forces change over time.

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