Looking for Fun, NO PREP Valentine's Day Science Activities. This is the perfect way to add fun without sacrificing learning time! This collection of Valentine's Day Activities was designed for secondary science classes. It includes three fun activities that are easy to add to your day! Each activity combines relevant science facts directly related to Valentine's Day. These activities are perfect for bellringers/warm-ups, extra credit, early finishers, class parties, incentives or just some fun!