We used mud as a landing pad for our marble drop, using a couple different weight marbles and dropping them from different heights. Depth measurements were taken and charted on the backside of some Christmas wrapping paper we taped to the wall. Many of the wrapping papers sold now have grid-lines on the inside to help cut straight lines and this makes for a nice big graph too.
After this the kids dropped a book off the front porch (second story) at the same time as a piece of paper to see which would land first. Then they dropped that same book with the piece of paper on top of the book. They continued with items of varying weights and then moved on to action figures which needed to land more slowly so as not to cause damage to the "person." So they came up with several parachute ideas and tested them to find the most effective.
For lunch the kids made earth balls, following a recipe from the KONOS inquisitiveness unit. We did make one adjustment. For the core we used peas instead of walnuts. I shredded some cheese ahead of time and made the hamburger mixture for meatballs. The kids used the cheese to surround the peas one at a time. Next the cheese balls were moved down the assembly line where another child wrapped it up in the meatball mixture. All the meatballs were spread onto a baking pan and baked until cooked through.
Now some of the cheese will melt out through the meat but they are so yummy anyway. And the kids LOVED them. :)
After lunch the team got together to start the wall-size solar system. Each planet was scaled down so that with the sun as big as almost half the height of the wall the rest of the planets would be relatively sized. Then they were taped onto the wall at the same relative distance they would be from the sun. This was such a fantastic visual. I never realized how seemingly close the first four planets were and how very far out the final planets are.