This teacher did this for a preschool lesson, but it can be adapted for older kids. They could drop or open the balloons and observe what happens to the solid liquid and gas inside it. This would help identify the properties of solids, liquids and gases.
Lesson for introducing the scientific method.interesting since there are issue with the experiment used in the first lesson in knowatom that introduces the scientific method. The Science Penguin: Skittles and the Scientific Method
Force and Motion Experiment. This fits into the physical science. You could use tin foil, sandpaper, and cardboard to create three different surfaces to see which one has more friction. This could be used in a reading lesson setting.