Thinking of rockets, and trips to the moon brought to mind an experiment from Janice Vancleave's 202 Oozing, Bubbling, Dripping, and Bouncing Experiments, explaining the weightlessness astronauts experience while they are aboard an orbiting ship.
First, it's important to understand, that both the spaceship, and everything in it are actually free falling, while in orbit. To demonstrate the effect of free fall on an object inside another object, start with a paper cup. Use a pencil to make a hole in the side of the cup, near the bottom.
Fill the cup with water, and let the children see how it pours out hole.
Have them cover the hole with a finger, and hold the cup up high.
Then, while one child watches, the other should drop the cup straight down.
While the cup, and water are both falling at the same rate, the water will stop pouring out of the hole, and instead "float" in a state of weightlessness inside the cup (basically, anyway).
It took us quite a few drops to get the hang of dropping the cup straight down, but even our sideways drop, gave us a nice photo of water "rising" out of the cup, and went a long way to explaining why Don Knots had such a terrible time eating in "The Reluctant Astronaut", which is currently instant streaming on Netflix.
It's great to be a homeschooler.