氫氣

氢 = 气 + 又 + 工 : The Queen of Hearts (qi) is building a zeppelin in front of the engine ((e)ng1) by attaching a lot of hydrogen (氢) filled balloons (气) to a steel beam (工). In order not to accidentally pop a balloon with her finger nails she uses boxing gloves (又).

Mnemonic symbol: a balloon. The Queen of Hearts is disappointed by her balloons. She expected them to float upwards, but in the space station's bathroom, They float randomly in all directions.