泡

1. Origins, structure, and basic meaning

• Structure: 泡 is read as あわ and is a noun for a bubble or for foam made up of many bubbles in or on a liquid.
• Basic usage: Use 白い泡が立つ for foam forming and 細かな泡になる for breaking into small bubbles.

2. Common pitfalls and similar expressions

• Foam and bubbles
  • Soap produces foam viewed as a mass, while waves can scatter into many individually perceived bubbles.
• Expressions of formation
  • 泡が立つ describes foam rising, whereas 泡になる presents the result of waves striking rock and breaking into bubbles.