Ars Technica: Attaching a carbon monoxide molecule to the single-atom-tipped needle of an atomic force microscope allowed researchers to increase the device’s resolution. The unmodified microscope measures electric fields of molecules and surfaces by pressing with its needle. However, it does not have the ability to measure chemical bond strengths directly. In covalent bonds, electrons are shared by the atoms in the molecule, and the number of electrons shared increases the strength and shortens the length of the bond. The addition of the carbon monoxide molecule, which flexes under the pressure, appears to cause the bonds to stretch, allowing the microscope to measure differences in bond lengths down to 0.03 angstroms (3 × 10⁻¹² m).