Weight refers to how much a structure is affected by gravity. Loose Goo Balls, structure nodes (another name for attached Goo Balls) and structure attachments (also known as legs) have the same weight. The only Goo Balls with larger than normal weight are Beauty Goo, Ugly Goo, and Large Black Goo, which are appropriately larger. The attached Goo Balls weigh more than loose Goo Balls due to additional weight of the attachments. Thus heavy structures can be made by using Goo which can form more attachments between nodes, like White Goo.