Police in Germany are investigating a grade school teacher at a private school in the northern city of Lubeck for teaching his young students how to make pipe bombs and detonating it in front of them to demonstrate its force.

The newspaper Lübecker Nachrichten reported Wednesday that a spokesman for the Lübeck public prosecutor's office, Klaus-Dieter Schultz, said the investigation aims to determine if the 39-year-old teacher of The Free Waldorf School in St. Gertrude violated any law on the use of explosives. If the teacher, whose name was withheld, is found guilty, he may be fined or jailed for three years.

Hans Peter Scherer, the head of the association that runs the school, confirmed the investigation and said that the management, teachers and parents are supporting him. The teacher is not under arrest.

According to Spiegel Online International, the teacher has been teaching fifth grade students how to make gunpowder and pipe bombs since 2009 as part of a chemistry lesson. The pipe bombs were then detonated in an open field just 30 meters away from students.

From the close distance, the watching students felt the blast wave in their stomachs, though no one was injured, the report said.
A mother of one of the former students told the Lübecker Nachrichten, "No syllabus in the world contains something like this," referring to the bomb-making lesson.

Waldorf schools are known for its unorthodox teaching methods aimed at making children creative. The schools, which number 200 in Germany, were inspired by the ideas of eccentric Austrian philosopher Rudolf Steiner.

Schultz, who acts as the lawyer of the teacher, told Lübecker Nachrichten that there were allegedly two bomb explosions in 2010, but his client said there was only one occurring in March that year.

To make the pipe bomb, the teacher said he put black powder in a 10-centimetre long, 1.5-centimetre wide brass tube. The bomb was then set off by a sparkler.

A mother of one of the students reported the incident to the police in May 2011 sparking the investigation.
A spokesman of the conservative political party Christian Democratic Union criticised the teacher's actions.
Heike Franzen said explosives are not teaching materials.

Social Democratic Party spokesman for education, Henning, Hoeppner, branded the teaching method as irresponsible.
"This kind of action and a teacher who carried out an action, belongs to no school," said Antje Jansen, minority leader of the left, according to Lübecker Nachrichten.

The construction of a pipe bomb is relatively simple. According to Wikipedia, a steel water pipe is filled with an explosive material and then sealed with a cap. A fuse is inserted into the pipe with a lead running out through a hole in the side or capped end of the pipe. The fuse can be electric with wires leading to a timer and battery or can be a common fuse. Upon explosion, the pipe fragments producing shrapnels.

Assembling a pipe bomb is dangerous with premature detonation likely due to improper handling or constructions. Cases of pipe bomb makers being killed in a blast were reported in the past.

A pipe bomb made from a steel pipe joint.