plunges is a form of:

Strontium



noun
1.
(a soft silverwhite metal having a radioactive isotope) សារធាតុគីមីហៅស្ដ្រុងចូម (ពណ៌រាងទឹកប្រាក់រឹង)
ENGLISH MEANING
noun
1.
A metallic element of the calcium group, always naturally occurring combined, as in the minerals strontianite, celestite, etc. It is isolated as a yellowish metal, somewhat malleable but harder than calcium. It is chiefly employed (as in the nitrate) to color pyrotechnic flames red. Symbol Sr. Atomic weight 87.3.
2.
A radioactive isotope of strontium produced by certain nuclear reactions, and constituting one of the prominent harmful components of radioactive fallout from nuclear explosions; also called radiostrontium. It has a half-life of 28 years.