Practicum: Charge on a Balloon

LAB PRACTICUM - Finding charge on a balloon

Purpose - Determine the number of extra electrons on charged balloon by using Coulombs law.

Data -
mass of balloons (kg)
length of string (balloon to ceiling) (m)
distance between balloons (m)
angle between balloons

In picture - 1 meter = ___mm (Scale for measurements)

No graph

(0) Use scale to determine length of string and distance between balloons for data table and convert mass from grams to kg.
1. Calculate Fg of balloon (Fg = mg; use 9.81 N/kg)
2. Calculate angle from center line to string tension - (angle between balloons / 2)
3. Calculate Fe -->
Coulomb balloon.JPG
4. Use Coulombs law to solve for charge (assume both balloons have same charge)
5. Use charge to solve for number of electrons ( 1 coulomb = 6.24 x 10^18 electrons)

1. Why did you have to use the picture to measure the distance between the balloons?
2. Compare your number of electrons to other groups. Why do they vary?
3. This number is only excess electrons. How could you figure out total electrons on the balloon? What do you need to know?

Conclusion -
Restate purpose,
List results (How many electrons on balloon?)
Justify your results.
Statement of errors - list 3 and be specific!