Lake Tekapo was formed by glacial action during the last ice age. That is to say the lake is situated in a glaciated valley. It is fed by the Godley River, which originates from the Godley Glacier. The bottom sediments are silty clays. The sediments are influenced by glacial meltwater, giving the lake its distinctive light turquoise colour. This Sunday morning a loud continuous siren went off. We wondered what was happening. It was a warning they were opening the dam which we overlook. The outflow from Lake Tekapo is controlled to regulate water levels for hydro-electric power generation.

Unbelievable how heavy even the smallest rock is here. Liz made a lovely cairn, photographing it from its best side. Unlike me. We may pop back tomorrow to see it. There is a great walk along the shore here. Today the mini golf was rather straight forward, except for the hole shown, where the hole is on top of a narrow hump and you can so easily windscreen wipe into the region of six shots.

Cooling down in the hot springs we noticed a whirlpool above the drain in the pool. It was persistent, even when we disturbed it and a couple sitting on the side became interested as we were trying to remember if it was rotating the other way round to the UK. They said they would google the Coriolis effect, but then another couple paddled over. They said they heard us talking about the Coriolis effect and asked why we were. When we told them, they were surprised. They were pilots and knew this effect as a bad thing can happen to pilots eyes in the dark. We had a long chat about our holiday and upcoming Australia bit.

If you want to know more about the plug hole, Coriolis effect read on. This can be visualized if you imagine putting a pan of water on a turntable and then spinning the turntable in a counter-clockwise direction, the direction in which the earth rotates as seen from above the north pole. The water on the bottom of the pan will be dragged counter-clockwise direction slightly faster than the water at the surface, giving the water an apparent clockwise spin in the pan. But if you were to look at the water in the pan from below, corresponding to seeing it from the south pole, it would appear to be spinning in a counter-clockwise direction. Likewise, the rotation of the earth gives rise to an effect that tends to accelerate draining water in a clockwise direction in the Northern hemisphere and counterclockwise in the Southern.

Dinner from the ready meal microwave department tonight, Mac n Cheese & Tika Massala in our wonderful apartment.