If you want to find a great STEM activity then I recommend Robotis PLAY 600 Pets. This is by far the best project we’ve done. Once built the design actually moves! The kit comes with everything except batteries (AA x2). The manual shows you how to make 3 designs but you can go online and get 4 more projects to make using the same kit.
It is a bit hard for our daughter to put the connectors in but she’s 4. So instead I have her get the pieces and show me where they need to go and I put them in. Taking apart the design was quite difficult. I couldn’t get the connectors to come out. In the end I use a pair of tweezers to take the project apart.
Once we finished building the first project (bird), our daughter played with it all day. She can’t wait to build another one. For her to love doing an activity so much is wonderful and is why I highly recommend Robotis. I got it with our Timberdoodle curriculum for this year. There is no better learning than hands-on activities.