Waiakea High School was locked down Thursday morning after the discovery of a “suspicious object” on campus, according to a Hawaii Police Department alert.
Police later determined the item to be a school project.
The school went into lockdown at 11:48 a.m., and first responders arrived shortly thereafter, including members of the Hawaii police and fire departments and a hazardous materials response vehicle.
Police kept drivers from entering the parking lots and directed journalists not to stand on the sidewalk along the front of the school, telling them to stand on the opposite side of Kawili Street.
The lockdown was lifted at 12:24 p.m. No injuries were reported.
In a prepared statement, Waiakea Principal Kelcy Koga described the object as a water bottle with a piece of metal inside it. That fits the description of a “bottle bomb” that was set off at Hilo High School just over a month ago. No one was injured in that instance, but two students were arrested in connection with the disturbance, which locked down the school for more than an hour.
“The device was found by a custodian around 11:45 a.m. on a grassy area in the center of the campus, and it was a bottle with water and what looked like metal inside,” Koga said. “A lockdown was initiated for precautionary reasons. Police were called to the campus, and they removed the object, that was identified as a Cartesian diver science experiment a student had inadvertently left from a previous period.”
The Cartesian diver is a classic science experiment attributed to Rene Descartes which demonstrates the principle of buoyancy, using a small tube floating inside a container filled with water. When the bottle is squeezed, the tube dives to the bottom of the container because of the change in pressure.
Bottle bombs are small devices made with a plastic bottle filled with cleaning chemicals and a strip of metal which, when shaken, sets off a chemical reaction that causes the bottle to burst.
Email Colin M. Stewart at cstewart@hawaiitribune-herald.com.