Brain freeze is a term Canterbury University mechanical engineering student Hamish Laing knows well after twice braving polar plunges. The 22-year-old has just returned home to Christchurch after about two months on the ice with Antarctica New Zealand as one of Sir Peter Blake Trust's Antarctic youth ambassadors.
He packed in a lifetime of experiences but the most testing was his double plunge through a hole in sea ice beside Scott Base into freezing waters below.
"It was a surreal feeling to stand at the edge of the hole with nothing on but a pair of undies but I had my lucky red socks on so I was confident of a successful plunge," he wrote on his blog the day after the December 28 jump.
"I clearly wasn't thinking straight after the first jump because I turned round and went back for round two. Surprisingly, it was actually worse the second time and, although my body felt fine, my head was starting to feel numb. I was probably in the water no longer than 30 seconds in total but that was enough for me." Safety was top priority with all participants wearing harnesses in case they needed to be pulled out fast from the -1.8degC water.
Laing, vice-president of the university's Engineers Without Borders chapter, applied to the trust last year after Antarctica captured his imagination as one of the hardest places on earth to reach. He plans to focus his masters studies this year on renewable and sustainable energy so it appealed to his environmental interests plus his passion for the outdoors and skiing.
"And it's a home of legends, such as Scott and Shackleton."
Visits to Ernest Shackleton's hut at Cape Royds and Robert Falcon Scott's two huts at Cape Evans and Hut Point were definite highlights, he said.
Over summer, he worked with Scott Base engineering staff, learning how it operated.
"There's quite a bit of work that goes on behind the scenes. They do everything that keeps the base running and the people happy."
Their problem-solving in the harsh and remote environment was an eye-opener, he said.
"It's definitely a challenge. There are all sorts of issues that these guys will encounter here that they definitely wouldn't have seen back in New Zealand."
Scott Base was an interesting test case for sustainability with every aspect, including water and power use, plus food and human waste, monitored for efficiency.
"If they took half as much care back home or overseas as they did there, then maybe we'd see some changes," he said.
His trip offered some unusual experiences, such as waking up on Boxing Day with snow falling on his face after sleeping the night outside in a snow trench, running the annual ice marathon across Ross Ice Shelf, playing in an annual outdoor rock concert Icestock on New Year's Eve and taking a helicopter flight to the Dry Valleys, one of the driest places on the planet.
Witnessing Antarctica wildlife up close was also memorable.
"When we were up at Cape Royds sitting on a rocky knoll overlooking the ocean, there was a bunch of emperor penguins just on the ice below us and the adelie penguins were walking to the ice edge and jumping off and then out popped some orca whales. It was just incredible. Moments like that are pretty special."