PLEASE HELP

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mishaalkhan
Posts: 1
Joined: Thu Feb 23, 2017 6:26 pm
Occupation: Student

PLEASE HELP

Post by mishaalkhan »

hi we're working on a surface tension project:
https://www.sciencebuddies.org/science- ... p012.shtml
and we don't know what s is in this formula
F = 2sd, where
F is the force, in newtons (N),
the factor of 2 is because the film of water pulled up by the needle (or wire) has 2 surfaces,
s is the surface tension per unit length, in units of newtons/meter (N/m), and
d is the length of the needle (or wire), in units of meters (m).
To convert grams to the force, F, you have to account for gravity pulling down on the mass in the pan. Calculate the total mass in the pan by multiplying the number of pins (or drops of water) by the mass of a single pin (or drop of water), which you calculated in step 4.d. Then multiply the total mass (in grams) by 9.81×10-3 N/g (for more information, see the reference about gravitational force in the Bibliography).
You can rearrange the equation above to solve for s, the surface tension of water. Measure the length of the needle (or wire), and you'll have all the information you need to calculate the surface tension of water.

We would really be grateful if you could help us because the report for this is due tomorrow. :D
kaylimasuda
Former Expert
Posts: 52
Joined: Sat Jun 11, 2016 2:59 pm
Occupation: Student

Re: PLEASE HELP

Post by kaylimasuda »

I'm sorry that I replied too late since my check-in day is Friday. In the formula F=2sd, s=surface tension, and d=length of the needle resting on the water. I hope that everything worked out!

-Kayli Masuda
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