Getting ketchup out of the bottle isn’t always easy. However, shaking the bottle before trying to pour allows the thick, gooey ketchup to flow more freely because it becomes more fluid when agitated.

In a new study, scientists show that two fundamental physical constants govern how runny a liquid can be. Their equation relates the minimal value of elementary viscosity (the product of viscosity and ...

When that pressure is removed, the capsules pop back into their spherical shape. That transition changes many of the liquid's properties, including its viscosity and opacity. Those properties can be ...