By heating balls to 400C and dropping them into 90C water, the 20 mm balls were encapsulated by a tear-shaped cavity that was five to 15 times their size, which cut through the water like a hot knife through butter. Against a similar tear-shaped piece of plastic, the treated balls had 90% less drag

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By heating balls to 400C and dropping them into 90C water, the 20 mm balls were encapsulated by a tear-shaped cavity that was five to 15 times their size, which cut through the water like a hot knife through butter. Against a similar tear-shaped piece of plastic, the treated balls had 90% less drag