6. What makes plastic bottles a big concern in oceans but not other materials such as metals, wood or paper materials? 3 points
Bottle caps are light weight and MORE dense than water, so they float.
Water bottles are made of PET plastic, which is LESS dense than the ocean water so they sink to the bottom.
Bottle caps are light weight and LESS dense than water, so they float.
Water bottles are made of PET plastic, which is MORE dense than the ocean water so they sink to the bottom.