If you’ve ever whacked the bottom of a ketchup bottle to get that tasty tomato goop flowing, you’ve put some serious physics to work. Ketchup is a non-Newtonian fluid. So are toothpaste, yogurt, ...

Have you ever turned a liquid into a solid just by tapping on it? Watch this fun video and learn how to conduct a viscosity experiment at home with a few simple steps! Click here to download a PDF of ...