Have you ever been outdoors during the summer heat and wished you could have a cold drink without lugging an icebox around? Then the "Polarcan" may be an invention to look out for.
Winners of this year's Joint School Science Exhibition (JSSE), four Form Five students from SKH Bishop Mok Sau Tseng Secondary School applied chemistry from their textbooks to solving a real-life problem.
The Polarcan is a simple way of cooling a drink: water is added to a premixed powder of citric acid, sodium hydrogen carbonate and urea, which creates an endothermic, or heat-absorbing, reaction and leaves the drink chilled.
The only tools needed are a few plastic bags to hold the drink and the powder, and a waterproof pouch to hold the entire mixture.
The idea for this invention came after the team saw self-heating cans. Alex Lam Cheuk-fung says: "We wondered if we could use the same sort of idea, except to cool a can instead of heating one.
"We thought of making a dehumidifier to fit the 'Seasons' theme but that seemed like a common idea that would get us laughed at."
Researching the formula was simple, according to Galen Wong. "We just went online to look. We found a way to cool a can using compressed gas, but we decided against that due to cost, as well as environmental and safety issues."
True to their priorities, the current product is fairly low cost at HK$7 a batch, and could potentially drop below HK$1 per batch if bought wholesale. Its main byproduct is carbon dioxide, which is not overly polluting, and the chemicals used are non-toxic.
The exhibition, held in the Central Library last month, was where the products were examined by both judges and the public. The team found this to be the most difficult part of the process. Galen explains: "It was a five-day exhibition, from 10am to 7pm. It was like working overtime."
Though members of the public were free to come and ask questions, Marcus Leung Hei-long says: "The judges are the only ones who pay attention to the formulas and figures. Different people look at different things."
Galen adds: "Some people care about the environmental or the safety aspect. Some might care more about the cost. Different people have different priorities."
The team says they did not expect to win. With other teams winning the "best proposal" awards and their booth being far from the "most popular", they expected to go home empty-handed.
"I joked, 'if we can't win the most popular booth, let's go for the championship'. This actually coming true was both exciting and surprising," Marcus says.
The team wants to bring the Polarcan to market, but they say their product is not quite ready at this stage. Brian Pang Chun-sum says: "We might start applying for a patent. We'll need to refine our product further and then see if it goes anywhere."
The team thanked their fellow students for helping at the booth, as well as the school for lending their support during testing, the lab technicians, and their teacher-adviser, Miss Lam.
If you're a budding inventor hoping to enter the JSSE, the team also suggests avoiding the DSE scramble. Galen says: "Doing this sort of competition early is better. Form Four is the best time to take part."
Some cool advice from some cool guys.