Heterogeneous mixtures are not uniform. If you take two samples from different parts of the mixture, they will not have an identical composition. You can use a mechanical method to separate components of a heterogeneous mixture (e.g., sorting candies in a bowl). Sometimes these mixtures are obvious, where you can see different types of materials in a sample. For example, if you have a salad, you can see different sizes and shapes and types of vegetables. In other cases, you need to look more closely to recognize this mixture.