You tube is blocked for our students, so I use the school tube and kids tube. We used the school tube last year to look at the videos on how to design a pop-pop steam boat. My students using the videos on School tube created the boat successfully. They also added they own inventions while creating the boat. This will a great tool for them to create their own video and their experience to share with others some challenges and how they worked around it.
Here is the video on pop pop steam boat, there are several parts to it and it is made from a soda can.
We use Angel learning system in our school and use the drop box for students to submit the assignments.