energy in the oil nucleotide has constant want & energy in the oil cans has constant size ->  matter in gas phase has variable volume and shape  matter in gas phase has variable volume and shape & energy with constant want and size expands to past the size and weight of its part bat ->  gas will expand to fill the shape of the container  gas will expand to fill the shape of the container & land is a mean of oil -> air will expand to fill the shape of the container