Vacuum_bazooka
Vacuum bazooka
Pipe-based cannon
A vacuum bazooka is a pipe-based cannon which uses a vacuum pump (often a vacuum cleaner) to reduce pressure in front of the projectile and therefore propel a projectile as a result of the air pressure acting on its reverse. The concept was originally proposed by Neil A Downie in 2001[1] but many variations have been built since.[2][3]