 Everything we see is made of atoms. But what can these tiny particles tell us about the big, wide world? Quite a lot actually. Techniques looking at different types of atoms help uncover important clues about things. Just as a fingerprint can identify a person, studying atoms can help trace the origin of water, objects, and food. So, what is an isotope? You may have heard of elements like carbon and oxygen. Atoms of the same element share chemical properties. But they can vary in mass, depending on the number of neutrons. These atom varieties are called isotopes. For example, carbon is an element with different isotopes. Most isotopes occurring in nature are stable. This means they don't emit radiation. How does it work? With special machines, scientists can separate isotopes based on weight and count their amounts and proportions. This reveals a unique identity or isotopic signature which can help determine where food was produced, the source and quality of water. It can even help find the right amount of fertilizer to use for crops. Stable isotope techniques are used to detect food fraud, improve agriculture, and better manage natural resources.