Capillary Action- Rate/Temp- How would you analyze?

In summary, the conversation was about an experiment done by a 9th grader for a science fair, measuring the effect of fluid temperature on capillary action in paper. The results were surprising and the person was seeking advice on how to analyze the data. The potential explanations for the results were discussed, including the relationship between temperature and viscosity and the impact of pressure on the experiment.
  • #1
miata
1
0
Hi Folks -

This started out as a simple experiment we could do for my daughter's science fair (9th grade). Now I am truly ashamed to admit that I don't really know the best way to analyze the reasonably good results of the experiment.

The experiment was to measure the effect of fluid temperature on capillary action in paper. We set up a frame to hold strips of paper in tension, suspended so they weren't touching the frame where the fluid wicked up the paper. The ends of the strips were dipped in the water to some consistent "zero" point and the height of the fluid was measured at regular time intervals. We measured this at room temperature, and the water bath was (1) room temp, (2) ice water, and (3) heated to an initial temperature of 98C, but cooled to about 54C over the course of the experiment. Note that I tried to get my daughter to do a better job with the hot experiment, but she was lazy and stubborn, so be it.

We experimented with about 8 different types of paper (itself an interesting experiment) and finally selected one particular paper napkin that gave a slow enough rate to be measurable easily at regular time intervals and was fast enough that each experiment could be concluded in 30 minutes.

The results were actually more dramatic than anticipated. I posted them here:
height vs time for three fluid temperatures:

mooney.50megs.com/images/capillary.jpg
(sorry, you'll have to cut and paste, as they won't let a newbie post a link!)

I've got some ideas how to analyze this, but have been frustrated as to how rusty my skills have become. And so I kindly ask: How would you analyze this experiment?

- Many thanks in advance.
 
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  • #2
Viscosity tends to fall as temperature increases (for example, water viscosity goes from 1.79 cP to 0.28 cP in the temperature range from 0 °C to 100 °C)
http://en.wikipedia.org/wiki/Viscosity" [Broken]

Regards
 
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  • #3
well yeah lower viscosity is more fluidity thus faster motion, but do they teach viscosity to 9th graders? another explanation would be that Pressure is P= Rho*g*h, Rho being the density of liquid, g is the gravitational constant, and h is the height reached by the liquid. since ur experiment is close to a barometer i think it measures the ambient pressure, and since Rho lessens with heat, h has to increase so that the pressure remains constant, but i think you need to verify this idea
 

1. What is capillary action?

Capillary action is the process by which liquids move through narrow spaces, such as small tubes or between the fibers of a porous material, due to the cohesive and adhesive forces between the liquid molecules and the surface of the material.

2. How does temperature affect capillary action?

Temperature can affect the rate of capillary action in two ways. First, as temperature increases, the kinetic energy of the liquid molecules also increases, which can lead to faster movement and therefore a faster rate of capillary action. Second, temperature can also affect the surface tension of the liquid, which in turn can affect the strength of the cohesive and adhesive forces involved in capillary action.

3. How can I measure the rate of capillary action?

The rate of capillary action can be measured by placing a liquid in a narrow tube or capillary and recording the time it takes for the liquid to rise a certain distance. The rate can then be calculated by dividing the distance by the time. The rate can also be measured using more advanced techniques, such as using a high-speed camera to capture the movement of the liquid.

4. How do different liquids compare in terms of capillary action?

Different liquids can have different rates of capillary action depending on their surface tension and viscosity. Generally, liquids with lower surface tension and higher viscosity will have a slower rate of capillary action compared to liquids with higher surface tension and lower viscosity.

5. What are some real-world applications of capillary action?

Capillary action has many practical applications in everyday life, such as in paper towels and sponges, where it helps to absorb liquids. It also plays a role in the transportation of water in plants and the movement of groundwater in soil. Capillary action is also used in advanced technologies, such as in microfluidics and lab-on-a-chip devices for medical and biological testing.

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