My marble machine has been in use lately so my son was excited to build one when I brought it home. I helped him with the placement and taping the ramps to the pegs, but he chose the parts.
Afterwards, I built my own marble machine.
This one differed from others I built because it stops the marble in the middle of the machine by crashing the marble into a short domino run. A LEGO WeDo tilt sensor tells Scratch when to play some of Brahms Lullaby, while a WeDo motor starts and pushes a second marble back into the run.
I tried to place some of the ramps away from the peg board to vary the design. I also incorporated the computer into the marble machine itself because the OLPC could hang from a couple pegs. The antenna on the OLPC helped hold the final tube in place, too!
I like the combination of easy to work with materials such as cardboard and pre-cut wood ramps, as well as more advanced tools like the laptop, WeDo, and the uphill ramp.
This marble machine pushed me to think in some new ways. The addition of the domino chain reaction in the middle opened a new creative challenge. As always, LEGO WeDo in a marble machine adds an extra element of "magic" to the show.