Abstract: A container includes an upper chamber, a lower chamber, and a physical actuator, and may include chambers. Each chamber includes a different substance. Each chamber is sealed off from adjacent chambers and the atmosphere. At least one of the chambers is sealed at below atmospheric pressure, which helps hold that chamber in contact with one or more of the other chambers. When the physical actuator is activated, the seals between the chambers are opened to each other and atmosphere, which causes the substances to mix together in the chamber that was previously maintained at below atmospheric pressure. The change in pressure differential also assists in the mixing.