Maslow's Hierarchy of Needs. Definition. Maslow's hierarchy of needs is a theory of motivation and personality developed by the psychologist Abraham H. Maslow (1908â1970). Maslow's hierarchy explains human behavior in terms of basic requirements for survival and growth.
When you use ice to cool the ingredients for ice cream, the energy is absorbed from the ingredients and from the outside environment (like your hands, if you are holding the baggie of ice!).
Yes. When water, for example, changes its physical state from one in which the molecules are tightly packed together to one in which they are loosely packed (as from ice to water) energy is necessary to effect the change. The amount of energy needed for one gram of ice to change to water is 80 calories (335 joules).