Certain force to break surface tenson of Jelly

In summary, a person is designing a structure to rest on top of jelly and needs to determine the maximum weight the structure can hold without breaking the surface tension of the jelly. They are having trouble finding the solution and are seeking help from others. The solution involves multiplying the surface tension of the jelly by the length of one of the sides of the jello cube. If the surface is a jello rectangle, the smaller of the two sides should be used. However, it is unclear what to do if the container is circular. The units for pressure and surface tension should be equivalent.
  • #1
Sam223344
12
0
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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  • #2
This is exactly like a similar question posted elsewhere here... is this some sort of homework question?
 
  • #3
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.
 
  • #4
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.
 
  • #5
Jelly is not a viscous fluid. Have you found the mechanical properties?
 
  • #6
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.
 
  • #7
Canterbury University students aye. I am also stuck, any help is welcome.
 
  • #8
Is the jelly in a container or acted upon by any other forces?
 
  • #9
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?
 

1. What is surface tension?

Surface tension is the force that causes the surface of a liquid to behave like a stretched elastic membrane. It is caused by the cohesive forces between the liquid molecules, which pull them together and create a strong surface film.

2. How is surface tension measured?

Surface tension is typically measured in units of force per unit length, such as dynes per centimeter. It can be measured using a variety of methods, including the drop weight method, where the force needed to pull a drop of liquid apart is measured.

3. What is the certain force needed to break the surface tension of jelly?

The certain force needed to break the surface tension of jelly depends on several factors, including the type of jelly, its temperature, and the size and shape of the object used to break the surface. In general, a force of at least 1 dyne per centimeter is needed to break the surface tension of jelly.

4. How does the surface tension of jelly compare to other liquids?

The surface tension of jelly is generally higher than that of water, which has a surface tension of about 72 dynes per centimeter. This is because jelly contains more dissolved solids and proteins, which increase its cohesion and surface tension.

5. Can the surface tension of jelly be altered?

Yes, the surface tension of jelly can be altered by changing its temperature, adding certain substances (such as salt or sugar), or physically manipulating the jelly. These alterations can affect the strength of the surface tension and the certain force needed to break it.

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