This document discusses an experiment where a plastic ruler is rubbed and then attracts paper scraps. The ruler carries an electric charge after being rubbed, exerting an electric force on the paper. Atoms are made up of protons with a positive charge, neutrons with a neutral charge, and electrons with a negative charge, which can explain where electric charges come from.

1. EXPERIMENT
After being rubbed a plastic
ruler can attract paper scrapes
Ruler carries electric charge. It
exerts electric force on paper.

2. Where do charges come from ?
Matter is made up of atoms.
Proton (Positive Charge)
Neutron (Neutral)
Electron (Negative Charge)