One of the country's brightest young minds has developed a way to make bacteria less resistant to antibiotics.

Another has created six new types of bioplastic including one which decomposes at 300 times faster than plastic.

Two brothers have come up with a laser device to make road cycling safer.

The students were among 26 finalists in the BHP Science and Engineering Awards. In a testament to the quality of the work, these projects weren't the winners.

The four award categories are engineering, investigations, innovator to the market and the teacher's award, with the winners announced at an event in Melbourne on Tuesday.

Ever wondered if noxious fireweed, often eaten by sheep, is moving through the food chain and onto our dinner plates? That was Bega student Jade Moxey's experiment, which took out first place in the investigations category.

Have you ever thought about creating a new type of musical instrument? Toorak's Justin Mitchell came first in the engineering section with his design of the "hood-wind" instrument, a device stored in the pockets of a hoodie that allows the user to compose and play electronic music, heard only by the wearer.

Have you ever thought about chocolate? Not craved it, but really thought about where it comes from? Winning the blue ribbon for innovation to market, Adelaide's Amber Kraczkowska wanted to find the most effective composting system for the waste product of cocoa, where 40 million tonnes of cocoa shells amass every year from chocolate production.

The teacher's award winner Hamish Gibson said the work and findings were phenomenal.

As head of science at Georgiana Molloy Anglican School in Busselton, WA Mr Gibson said there was nothing more rewarding than seeing a student go beyond their learning in the classroom.

"They're doing something that makes a difference in their own lives," Mr Gibson said.

"Often their choice of project is serendipitous. They come up with ideas for projects based on some of the things they encounter in their own lives."

Mr Gibson said the fireweed project by Miss Moxey, who lives on a farm with her family, was a prime example.

"When you give them a platform to inform those ideas with the STEM approach, it's really amazing to see what the students can produce."

Australia's Chief Scientist Alan Finkel said it was students like these who would lead Australia into the future.

"In a world of rampant change, science literacy is one of the most important tools we can give to our youth," Dr Finkel said.

"Science and engineering studies provide students with more than just a pathway to related jobs; they teach skills with applications right across the economy, from quantitative analysis to data gathering, prototyping, experimentation and more.

"And history is littered with science and engineering students who used their skills to thrive in other fields. CEOs, politicians, entrepreneurs and film directors - the list goes on," he said.

Science, technology, engineering and mathematics - the STEM subjects - are the subject of a 10-year school education strategy implemented last year.

The plan stated participation in senior secondary science and advanced maths had stalled or declined, and reversing that trend would take time and effort.

"Building young people's engagement in STEM is bigger than schools and what happens in the classroom," the plan stated.

For many students involved in the awards, their work happened outside of class.

Canberra teen Rose Weller discovered a way to detect previously undetectable steroids in athletes. Miss Weller worked with a research team at the Australian National University to develop the idea. She was the first school student in 15 years to be invited to conduct post-graduate studies at the university.

CSIRO chief executive Larry Marshall said it was critical to support and promote STEM for students.

"These awards are an innovative and inspiring way to connect with future STEM professionals and encourage them to join us in tackling the challenges of tomorrow," Dr Marshall said.

BHP Billiton Foundation chairman Karen Wood said she was proud of what the awards aimed to achieve.

"[They encourage] students to explore, research and delight in the study of science, and challenge their understanding of the world around them," Ms Wood said.

Mr Gibson said selected finalists would go on to represent Australia in the biggest science event of its kind, the Intel International Science and Engineering Fair in America in May. The designs and ideas could be picked up by the likes of Google, Apple and other innovators. The top STEM universities also offer bursaries and industry scholarships at the event.

Devices like a built-in solar charger for a mobile phone or tablet, findings which show endemic fungi can help break down plastic, and a way to naturally and effectively clean up oil spills were all explored by teenage science students as part of the competition.

For Queensland's Amy Zhou, who found a way to disrupt a protein structure to make bacteria mutation more difficult and lower the likelihood of the bacteria developing resistance, science came naturally.

"I've always been really, really interested in science," Miss Zhou said.

"The first time I was really intrigued by science was when I saw how when sunlight hits the prism it causes a rainbow. I remember asking my dad how did that work, was it magic. My dad told me if I learned more about science I could unlock that secret, and pretty much everything else."

Declan Predavec, 13, and his brother Callum, 15, designed a device to help keep cyclists safe on the road. The device shines a one metre laser light onto the ground around the cyclist's back wheel, to help drivers pass at a safe distance.

"I feel like science and engineering just gives you the opportunity to explore, and innovate and try new things," Declan said.

"Part of the whole thing about science is discovering new things and disproving things and exploring all the stuff which just hasn't been thought about," he said.

Dr Finkel said these students represent the future of Australia.

"We don't know what the future will look like. But our best guess is that it's students like these – curious, engaged, and willing to look beyond the google search – who will lead us there," he said.