Spotters are very important for each child. Students can draw a plan. This is an activity no one forgets and is full of potential for math and science teachers. As a science teacher, when conducting investigations into the states of matter, it's easy to teach about solids and liquids. However, gases are another matter.
Balloons provide a common device with which most children have experience.
Yet, many students and adults do not believe that balloons can be that strong. The strength of the balloon skin combined with the force of the compressed air, provide a demonstration of the presence of the gas and how it can behave under pressure. Careful investigations can reveal answers to some of the questions in this article. As most teachers know, students will lead us to more ideas and then to the development of concepts, beyond what any of us alone can imagine. That is one delightful aspect of teaching with open-ended activities.