Floaters: What is the force that drives an isolated and floating piece of wheat or rice breakfast cereal through the milk to the side of the bowl where it aggregates with its companions?
Ice surprise: Last winter, we found a strange ice phenomenon in our garden (see photograph). The night had been cold, calm and cloud-free. I went out at 8.15 am and discovered that a plastic saucer which I had placed in the back garden full of tapwater had produced the strange tube-like structure shown.
What may not be apparent from the picture is that the tube is triangular in cross section and it is completely hollow down as far as the unfrozen water lying underneath the thick layer of ice. The fairly robust tube was an integral part of the underlying ice pool. We noticed that the outside of the tube was segmented in appearance, as though the ice had built up layer by layer.
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The saucer had been outside all night, situated well clear of any other object or fencing, some 2 metres from the house and it was not overhung by any trees.
There was no evidence of insect or other animal interference. The dark-coloured substance seen in the middle of the saucer is the remains of a leaf blown from a nearby tree, and had been in the water for some days.
I would be very grateful if someone could offer an explanation for this puzzling occurrence.
I can guarantee that unless some person or persons unknown spent a lot of time throughout the freezing night moulding this ice tube for no apparent gain, there was no tampering with either the saucer or the water.
Urine trouble: Surfers鈥� lore says that you should never urinate inside your wet suit as it is believed that the urine will attract sharks.
However, I would expect the opposite to be true. Shark blood has a very high urea content and it is also known to be a potent shark repellent. So why is human urine not considered so?