This is the second lab I do when covering static electricity. Students first investigate the attraction between a statically charged balloon and an aluminum soda can. The second part of the lab is the creation of Leyden Jar. The cool thing about these Leyden Jars is that you can make them with everyday objects, and they will store and accumulate the static charge from a balloon.
You can use a Leyden Jar to collect enough static from a balloon to create a small spark. Students can rub a balloon to develop a charge, rub the balloon on the paperclip of the Leyden Jar, and the jar will store the charge. It will store the charge for a many minutes up to several hours.
I have included a photo of Leyden Jars made from plastic milk bottles and film canisters. Any plastic bottle will work fine, and you can fill them with salt water or, if you can get your hand inside the jar, an inner layer of foil. The basic structure is a plastic bottle covered in foil and filled with salt water. Place a paperclip through the lid and into the salt water. You must be touching the foil on the outside of the bottle while charging the paper clip. This grounds the outside of the bottle and allows the charge to build up on the inside.
The lab is designed to have the students reverse engineer a Leyden Jar from one that you have made. You will be surprised how easy they are to make. It is best to have the foil tight up against the plastic bottle, but all of the bottles in the photo worked well.
With test leads, students can try to attach the Leyden Jars to each other. With many charged jars, they should discharge the bottles with a test lead rather than shorting them out with their fingers. On their own, a single small Leyden Jar does not store enough charge to give more than a minor shock.