Assertion: strontium 90's life | /r/HasProperty | the amount of time
Facets:
Source sentences:
text: The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-half of its original amount.
text: The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-half of its original amount.