Demonstrating Electrons

Name___________________________Class_________________________ Date__________


Purpose:  In this lab you will use the energy created by friction between a cloth (shirt) and a rubber balloon to investigate electrons and their properties.


Procedures:  Obtain an inflated rubber balloon and charge it by rubbing it on your shirt.  This transfers electrons from your shirt to the surface of your balloon.  Test the charged balloon’s ability to attract or repel the following items and record your observations.  Make a hypothesis of what you think will happen before you actually perform the experiment for each case.  Put what actually happens in the experiment and come up with an explanation of what happened.


Experiment                   Hypothesis                   Actual Results                           Explanation

Place the balloon

near small bits of



Place the balloon

near slow stream of

running water.


Place the balloon

near another charged



Place the balloon on

the wall.


Balance a meter stick

on the table & place

the balloon under

the meter stick’s

far end.


Post Lab questions:

1.      What subatomic particle was studied in this lab?______________________ What is its mass & charge? ___________________, _____________________

2.      Where does the particle reside?  (in or out of the nucleus?)

3.      Describe what you learned in this lab about electrons; specifically elaborate on the effort it takes to transfer an electron from one atom to another atom.

4.      What did you learn about the forces that occur between an electron and a positive charge? (like the balloon and your shirt after you rubbed them)

5.      What did you learn about the forces that occur between an electron and other electrons?  (like the two balloons after you charged them)

6.      Try creating two positively charged objects; what will happen when they are placed near each other?

7.      Why does the balloon with a negative charge attract the neutral board and other neutral objects?

8.      If one object gains electrons, what is its charge? ___________________________  What is the charge of an object that loses electrons? _________________________

9.      Can something become negatively charged without something else becoming positively charged?

10.   List 2 other subatomic particles in the atom.  What is the mass & charge of each?