How does soap water membrane thickness affect surface tension?

In summary, the conversation discusses the changes in surface tension of soap water when the thickness and concentration are altered. It is mentioned that if the thickness decreases while maintaining the concentration, the surface tension will change. Similarly, if the membrane of soap water evaporates, causing the thickness to decrease and concentration to increase, the surface tension will also change. However, before providing any further assistance, the person requesting help is reminded to show their own attempt at solving the problem.
  • #1
Chain Shawn
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Homework. Moved to Introductory Physics.
1.If the thickness of soap water surface decrease, whereas the concentration remain the same, how will the surface tension change?

2. If the membrane of soap water start to evaporate, its thickness become thinner and it’s concentration increase, How will the surface tension change?

Thank you!
 
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  • #2
Please show your own attempt at solving the problem.
 
  • #3
Chain Shawn said:
1.If the thickness of soap water surface decrease, whereas the concentration remain the same, how will the surface tension change?

2. If the membrane of soap water start to evaporate, its thickness become thinner and it’s concentration increase, How will the surface tension change?

Thank you!
PF rules require that you show us your best efforts in answering these questions before we can offer tutorial help. Please show us what you have done so far...
 

FAQ: How does soap water membrane thickness affect surface tension?

How does the thickness of a soap water membrane affect its surface tension?

The thickness of a soap water membrane can influence its surface tension. Generally, a thinner membrane has higher surface tension because the molecules at the surface are more tightly packed. Conversely, as the membrane becomes thicker, the surface tension may decrease slightly due to the distribution of intermolecular forces over a larger volume.

Why does a thinner soap water membrane have higher surface tension?

A thinner soap water membrane has higher surface tension because the molecules at the surface are more concentrated and experience stronger cohesive forces. This results in a higher energy state, which manifests as increased surface tension.

Can the surface tension of a soap water membrane be measured directly?

Yes, the surface tension of a soap water membrane can be measured directly using techniques such as the drop weight method, capillary rise method, or tensiometry. These methods allow scientists to quantify the surface tension and observe how it changes with membrane thickness.

What role do surfactants play in the surface tension of soap water membranes?

Surfactants, like those found in soap, reduce the surface tension of water by disrupting the hydrogen bonding between water molecules. They create a more stable membrane by forming a monolayer at the surface, which can affect the overall surface tension depending on the concentration and distribution of the surfactant molecules.

How does the composition of soap water affect the membrane thickness and surface tension?

The composition of soap water, including the type and concentration of soap, can significantly affect both the membrane thickness and surface tension. Different surfactants have varying abilities to reduce surface tension, and their concentration can influence the thickness of the membrane. Higher concentrations of surfactants generally lead to a thicker membrane with lower surface tension.

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