Almost everyone has experienced the frustration of trying to get ketchup out of a bottle. At first, nothing happens. The ketchup seems almost solid and refuses to move. Then, suddenly, it starts flowing, sometimes too quickly and all at once. Scientists call this surprising change in behavior “yielding.” Yielding happens when a material switches from […] The post Why ketchup suddenly pours: Scientists discover the hidden physics of soft materials appeared first on Knowridge Science Report .