Chemistry is the scientific discipline involved with compounds composed of atoms, i.e. elements, and molecules, i.e. combinations of atoms: their composition, structure, properties, behavior and the changes they undergo during a reaction with other compounds. Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds.
squash requires a brief heat treatment, called blanching, in boiling water or steam, to destroy the enzymes before freezing. Cook (blanch) the squash for 3 minutes. Begin counting the blanching time as soon as you place the squash in the boiling water.
After vegetables are blanched, cool them quickly to prevent overcooking. Plunge the green beans into a large quantity of ice-cold water (I keep adding more ice to it). A good rule of thumb: Cool for the same amount of time as the blanch step. For instance, if you blanch sweet green beans for 7 minutes, then cool in ice water for 7 minutes.