I do have a couple ideas and tips that may help you win. I don’t know how the guidelines are set up so if the ideas won’t be helpful I apologize.
First off put some ice cubes in the container then sprinkle salt on them, The reaction will create an effect and be super cold.
Another idea would be to get some dry ice if you able to, This will freeze it solid within seconds.
The last idea combines the the first. Take a bowl and fill it with with water and ice (Make sure the bowl is insulated) add a small handful of salt into the bowl, Put your drink into the cooler and before shutting stir then well then close and wait for the amount of time left, Your should have a cold water bottle.
I hoped this helped you out and I hope you also win the contest.
