This document describes an experiment demonstrating that saltwater is denser than fresh water. Materials needed include salt, two jars, a tablespoon, warm water, cold water, and two eggs. The experiment involves placing an egg in saltwater and fresh water, where the egg will float in the saltwater but sink in the fresh water due to saltwater's higher density from dissolved salt atoms. This same principle explains why people can more easily float in oceans and salt lakes compared to fresh water.