We just said that solutions represent homogeneous mixtures. When it comes to mixtures, solutions aren't the only important term to remember. We also have suspensions and colloids. Suspensions represent heterogeneous mixtures. In these heterogeneous mixtures, we have large solute particles that have the potential to float within the solvent. Then we have colloids. Colloids represent yet another homogeneous mixture. The difference now, in solutions, the particles completely dissolve within our solvent, so they're not easy to see. But in a colloid, there are intermediately sized particles that can also float within a solvent.
When it comes to their particle sizes, we're going to say for suspensions, the particles are larger so they tend to be greater than 500 nanometers in terms of size. And for colloids, they tend to be less than 500 nanometers. Because of their increased size, because they're larger, these particles will eventually settle, and they could settle either on the top or on the bottom. Where they settle really depends on the density of the solvent. But all you need to remember is that when it comes to suspensions, the particles being larger means they can eventually settle. Colloids, though, their particles are not as large. So these particles, they never settle. They never settle on the top or the bottom. They kind of stay suspended somewhere in the middle of the solvent.
Now, what are great examples of suspensions and colloids? Well, a great example for a suspension could be Italian salad dressing. Because in Italian salad dressing, what do we have? We have oil, vinegar, herbs, and spices. And if you really look at Italian dressing, you can see those particles floating around within the liquid. Examples of colloids, a great example would be milk. Now in milk, suspended within the liquid portion of it, you have fat particles, casein, and a lot of different things that are suspended within the milk itself. And these things are constantly floating within milk. They don't settle on the top or the bottom.
So just remember, solutions are homogeneous mixtures, but mixtures also can refer to suspensions and colloids.