Here's a riddle: What is the material that can be found in both plastic food containers and student-made rockets?

Answer: Polyethylene terephthalate (PET)

For the second time in four years, Singapore students used their knowledge of the plastic to propel their way to the top in the International PET rocket competition.

S'pore team

Held in Vietnam this year, the competition had required students to build and launch rockets using a combination of PET, water and compressed air.

A total of nine countries, including Japan and Malaysia, took part in the match.

From Singapore, six students from three secondary schools - Dunearn Secondary School (DSS), Bedok South Secondary School (BSSS) and Hougang Secondary School (HSS)- had taken part.

The Singapore representatives managed to win two of the top three titles.

Ian Tan from DSS had Quek Jun Wei from BSSS had emerged as the winner and second runner-up respectively.

The first runner-up title went to Japan.

Singapore last won the competition in 2006.

Winning factors

"The workmanship and the understanding of the Rocket Science are the two most important factors for the students," highlighted Mr Charles Tng, CEO of SpeedB, a Singapore-based company that teaches rocket science.

He also added that the Singapore winners had constructed rockets that were more "reliable" despite their technical difficulty.