We just finished a science lab that involved blowing items across the floor with a fan. Fun! Kutey came up with another idea she wanted to test. it involved putting the packing peanuts we had blown across the floor into the cardboard tube we had been using and trying to shoot them into the air...I told her to have at it.
This has led to 45 minutes of experimenting (with no direction from me!) to find the perfect combination to make the project work. Kiddo and Kutey have been trouble shooting, hypothesizing, testing, and ultimately succeeding! Engineering at work. Cost? Almost nothing--empty wrapping paper tubes, empty paper towel tubes, a few Di*ie cups, and packing peanuts. But what they are learning--all on their own--is worth so much more!
This is why I homeschool!