A playful variation of a classic puzzle becomes a fun gateway into the science of fluid dynamics — where gravity and design determine who gets milk.

Problem: Two cyclists are approaching each other with speeds of 2 mph and 3 mph. When they are 10 miles apart, a bird starts flying back...

Problem . Fred brings home 100 kg of potatoes, made up of 99% water. He leaves them outside, allowing for some water to evaporate, thus reducing the water content to 98%. How much do the potatoes weigh now? Answer . The new weight is 50 kg. Fig 1 . Potatoes contain about 80% water on average. Solution . At first glance, the answer might seem illogical. The water content dropped by only 1%, so the weight shouldn't change much. However, the solid content doubled from 1% to 2