When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locations.

This effect happens when water molecules interact with the aircraft and the sun shines through them.

These positively charged molecules interact with negatively charged particles and molecules to reduce the barriers to aggregation.

For example, mixing water and oil counterintuitively creates more order from a thermodynamics perspective, because of the way water molecules and oil molecules interact.

Signaling molecules interact with a target cell as a ligand to cell surface receptors, and/or by entering into the cell through its membrane or endocytosis for intracrine signaling.