A new model explaining this mysterious process suggests the core was created as dribs and drabs of iron percolated inward from Earth's lower mantle, according to a study published Oct. 6 in the journal Nature Geoscience. The mantle is the viscous, rocky layer between the crust and Earth's iron core.
Definition of flash card. : a card bearing words, numbers, or pictures that is briefly displayed (as by a teacher to a class) usually as a learning aid.
A flash card is a small data storage device that uses a flash memory chip to store data. Flash cards can be quite small in size, with a capacity of many gigabytes of storage. The memory in these cards is non-volatile, so it does not require a power source to remain intact.