PLEASE HELP
Posted: Thu Feb 23, 2017 6:37 pm
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.
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.