My grandson (age 7) and I built the six projects that come in this fun, water-powered set, together. Each of the models in the Water Power STEM Experiment Kit set ($29.95) use water pressure to make things move. Where many STEM toys are content to give you a kit to build, this one goes above and beyond with excellent supplemental reading materials and instructions. Speaking of instructions, you really have to follow them quite carefully to have success. For this reason having a grown-up helper (or older sibling guide) is advisable for kids closer to 8 than eighty. The best part is that when you’re done building the fun is only starting as you have a cool toy to play with!