Our kids just love experimenting with gravity and water. I made them these wall and deck activities with a quick stop at our local hardware store.
Here's a magnet ball and tunnel system. I picked up a sheet of metal and used base board frames to create the border. The tubes are made of clear ketchup dispensers and fastened together with electric tape. I fastened the magnets to the back and lined the tubes up in various ways to create a fun and interactive play.
I call this tunnel system tulips and tunnels. We combined the clear ketchup bottles with PVC pipes and connectors. The tunnels are attached with grey plastic electrical fasteners. The tulips are attached with velcro so the kids can pick flowers
Here's another version where the ball catches more air before entering another tunnel
Clearly I'm addicted to PVC piping! Here's another system I built off our deck. This is a water one! I attached a hose to the end and various on/off valves so the kids can have fun manipulating the water flow. This has been a true life savor for many summer afternoons.
Another angle to see the layout.
Improved on system by converting to White PVC pipes. It offers more pressure and I wanted to include a water gun show down feature. The kids also have more experiments with how to manipulate the plumbing and water flow.