Charges are actually present on every object but the positives cancel the negatives so the object is neutral. Lay the soda can on its side on the table. Charge the golf tube and bring it near the soda can. Note that the soda can is made of metal, not plastic as all of the rods are. Metals behave a little bit differently.
Charges are free to move around in a metal object.
The negative charges inside the soda can are repelled by the golf tube so they move to the far side of the can. The positive charges remain on the close side and they are attracted to the golf tube. As the electrostatic forces get weaker as distance increases the attraction between the unlike charges is greater than the repulsion between like charges. Here is the time to find out how the golf tube attracts hair and pieces of paper. Take a rod, charge it and bring it near the hanging rod.