Why is soap foam so good at blocking sound although it is mostly just air?

Question

I have noticed this while bathing when soap foam went into my ears and it almost completely blocked the outside sound. This seems weird as soap foam is just all air with some liquid

In: 18

Answer 1

Insulation is just a series of “bubbles” to block heat, or noise.

The best types of insulation have cavities small enough so they don´t actually have air in them.

Soundwaves also need parallel surfaces distanced on the right frequencies to travel through effectively. A series of random sized bubbles with curved walls will break apart sound waves and distribute sound, mufflling it.