Final answer:
A mixture of sand and water is considered a heterogeneous mixture because the composition can vary from point to point and you can visibly see the separate phases (solid sand particles and liquid water). These characteristics set it apart from homogeneous mixtures, where the components are evenly distributed and not separately visible.
Step-by-step explanation:
A mixture of sand and water is considered a heterogeneous mixture due to two main reasons.
- Variation in Composition: Just like Italian dressing, the composition of a sand and water mixture can vary from point to point. This variation occurs because the sand particles do not dissolve in the water and thus, depending on the concentration of sand to water, the consistency of the mixture can drastically change.
- Visibility of Different Phases: In a sand and water mixture, you can visibly see the separate contributions of sand (solid particles) and water (liquid). The inequality in distribution of the particles (settling of sand at the bottom and water at the top) makes it noticeable that the mixture is composed of two different substances.
Other examples of heterogeneous mixtures include chocolate chip cookies (you can see the separate bits of chocolate, nuts, and cookie dough) and granite (quartz, mica, feldspar, etc.)
Learn more about Heterogeneous Mixtures