How to Make a Catapult for Kids - this fun STEM Activity will keep them busy for hours! Four to six Popsicle sticks, three or more rubbed bands, glue (or glue gun), small cap, cotton balls or other small items (buttons?) for catapulting.
Human Body Ingredients via imaginaryfoundation: 'The average human has approximately 100 trillion cells and each cell is made of approximately 100 trillion atoms, each of which were originally created in the center of a star.' Here it is by mass: