In this experiment I made two glass ampoules myself from miniature test tubes. I held the test tube by its bottom end with gloves and then torched the tube about 1cm from its mouth. A propane blowtorch works well for this purpose. I rotated the tube a few times to evenly distribute the heat in a band around the tube and in about 30 seconds, the tube softened. I then used pliers to pull the mouth of the tube away from the rest of the tube by a few centimeters. Then, I slowly removed the test tube from the flame, letting it gradually get cooler. The end result was absolutely spectacular given the easiness of the experiment:
When the tubes are filled with crystal iodine (I will pour it down the thin neck of the ampoule), I will hit the narrow neck of the ampoule with the hottest part of the torch flame to rapidly melt it without heating up the iodine. Then, I will use pliers to pull the neck of the ampoule completely off, thus sealing the iodine inside. I am quite pleased to have such an easy way of making ampoules for chemistry stuff!