There are lots of ways to distinguish one type of bacteria from another, and you can learn some of the tricks at home with a cheap toy microscope: you might look at them, to see what shape they are, or what kinds of dyes and stains they pick up. You can see what shapes and colours the colonies make as they grow on ‘culture media’ in a glass dish, and you can look at whether certain things in the culture media affect their growth (like the presence of certain antibiotics, or types of nutrient). Or you can do genetic fingerprinting on them. These are just a few examples.
