What is in the spaces?

The idea

Even closely packed solids have some space between their particles, and these interparticle spaces are not filled with air; they contain nothing at all.

Closely packed

The particles of a solid are closely packed. Still, some space is left between them.

What do you think is in these spaces?

• Nothing at all
• Air
• Water

Zoom in

Zoom into a solid, then into one space between its particles. Then ask: could it be air?

Empty spaces

Even in closely packed solids, some space is left between the particles. These interparticle spaces are not filled with air. They contain nothing at all.

Interparticle spacing is least in solids, a little more in liquids, and most in gases.

• Idea | True?
• The spaces are filled with air | No: air is itself made of particles, with spaces of its own
• The spaces contain nothing at all | Yes

Notes

Even closely packed solids have some space between their particles. These interparticle spaces are not filled with air: they contain nothing at all.

Check yourself

What is in the space between the particles of a solid?

Is there any space between the particles of a solid?

In which state is the space between particles the largest?

• Air. Air is itself made of particles. The spaces between particles contain nothing at all.
• Nothing at all — correct. Yes. The spaces are empty.
• Smaller bits of the same solid. Constituent particles cannot be broken further, and the space between them is empty.
• No, the particles touch with no space at all. Even closely packed solids have some space between their particles.
• Yes, a little, even though they are closely packed — correct. Yes. Some space is left even in close packing.
• Yes, more than in a gas. Gases have the most space between particles. Solids have the least.
• Liquid. Liquids have a little more space than solids, but much less than gases.
• Solid. Solids have the least space between particles.
• Gas — correct. Yes. Gas particles have a lot of space between them.