How do phospholipids form membranes?

Phospholipids are a major component of cell membranes. They are ideal components of membranes due to their structure. They consist of a glycerol and phosphate 'head' attached to two fatty acid 'tails'. The tails are hydrophobic, meaning water-hating, and the head is hydrophilic, meaning water-loving. When many phospholipids are put in an aqueous solution such as the extracellular space, the hydrophobic tails move around in order to escape the water molecules. A formation that allows this is the lipid bilayer, in which the phospholipids form two rows, with the hydrophobic tails hiding on the inside and the hydrophilic heads on the outside. This creates a water-proof, insoluble barrier, making membranes effective at separating the inside and outside of a cell. This is also the structure of membranes surrounding organelles.