Certain force to break surface tenson of Jelly

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Discussion Overview

The discussion revolves around determining the maximum weight a structure can exert on jelly without breaking its surface tension. Participants explore the relationship between surface tension, weight, and the area of contact, as well as the mechanical properties of jelly.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks to calculate the maximum weight of a structure resting on jelly without breaking the surface tension, having already determined the surface tension in various units.
  • Another participant questions whether the inquiry is a homework problem, suggesting a potential similarity to previous discussions.
  • One suggestion involves multiplying the surface tension by the length of one side of the jelly structure, with a note to use the smaller side for rectangular shapes.
  • A participant challenges the reasoning behind the weight calculation, expressing skepticism about its validity across different sizes of jelly structures and suggesting that pressure may play a role.
  • Another participant notes that jelly is not a viscous fluid and inquires about its mechanical properties.
  • One participant shares their own struggles with similar questions and asks how to determine the surface tension and maximum weight the jelly can support, mentioning a small footprint constraint.
  • A participant identifies themselves as a student from Canterbury University and expresses a desire for assistance.
  • One participant asks whether the jelly is contained or influenced by other forces, seeking clarification on the setup.
  • A later reply clarifies that the jelly is in a clear container with specific dimensional constraints and notes that it is not acted upon by other forces until additional weight is added.
  • Another participant reiterates the question about the validity of the weight calculation and speculates on the relationship between surface tension and pressure units.
  • One participant revisits the multiplication of surface tension by the length of a side and poses a question about how to approach circular containers.

Areas of Agreement / Disagreement

Participants express various viewpoints on how to calculate the maximum weight that jelly can support without breaking surface tension. There is no consensus on the methodology or the underlying principles, indicating that multiple competing views remain.

Contextual Notes

Participants mention uncertainties regarding the mechanical properties of jelly and the assumptions involved in calculating weight based on surface tension. The discussion also highlights the dependence on the shape and dimensions of the jelly structure.

Who May Find This Useful

This discussion may be useful for students and researchers interested in fluid mechanics, material properties, and the application of surface tension in practical scenarios.

Sam223344
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I am designing a structure that can rest upon jelly. I know how to determine the surface tension of the jelly in N/m. I can convert this to dynes/cm, J/m^2 etc but that is'nt the problem.
I need to figure out the maximum weight of the structure so that its force on the jelly does not break the surface tension. How do i do this?
 
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This is exactly like a similar question posted elsewhere here... is this some sort of homework question?
 
Multiply the surface tension by the length of one of the sides of the jello cube. If the surface is a jello rectangle, use the smaller of the two sides.
 
Can you explain why that gives the amount of weight the jelly can hold? It doesn't seem reasonable when I'm sure the same weight would break the surface of the jelly whether it was a 20cm cube or 100m cube.

I'm thinking it has something to do with the pressure that the structure exerts on the jelly surface which would depend on the weight and area of contact of the structure.
Ive done a lot of research into surface tension but I cannot find what I'm looking for. If anyone could provide some assistance it would be extremely helpful.
 
Jelly is not a viscous fluid. Have you found the mechanical properties?
 
I'm doing the same kind of thing as you and have been at dead ends every where to find my answers. How do you determine the surface tension to start with? And then how do you find the maximum weight that the jelly can actually hold? we are allowed a small footprint in our final structure.
 
Canterbury University students aye. I am also stuck, any help is welcome.
 
Is the jelly in a container or acted upon by any other forces?
 
Jelly is in a clear container, made up to a volume of 500ml. The constraints say that the jelly must have a depth, width and height of at LEAST one cm. So it is not acted on by other forces until the tower is added.
 
  • #10
Sam223344 said:
Can you explain why that gives the amount of weight the jelly can hold? It doesn't seem reasonable when I'm sure the same weight would break the surface of the jelly whether it was a 20cm cube or 100m cube.


I'm Guessing so that the units for pressure and surface tension are equal (i.e ST has units N/M and P has units N/M^2)..?
 
  • #11
isabelle said:
Multiply the surface tension by the length of one of the sides of the jello cube. If the surface is a jello rectangle, use the smaller of the two sides.

And what if the container is circular? Would you multiply it by its circumference?
 

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