Applying physics to the properties and underlying structures of the molecules of life offers an insight into the mechanisms that make living beings tick. But even seemingly simple actions like muscle contraction involve a wide array of biological interactions, which has shrouded the dynamics and function of individual molecules behind a curtain of complexity. The scientific community has developed a powerful toolbox of methods to probe these interactions over the past two decades, uncovering previously hidden information about the structure, dynamics and function of individual biomolecules.