Qhov ntom yog hais txog qhov loj ntawm cov khoom hauv ib chav tsev ntim. Rau cov hlau hlau, nws qhov ceev yog ze ze rau nws qhov tshwj xeeb lub ntiajteb txawj nqus. Txij li lub ntiajteb txawj nqus tshwj xeeb yog txheeb ze rau qhov ntom ntawm cov dej, peb tuaj yeem suav qhov ntom ntawm cov hlau hlau los ntawm nws qhov tshwj xeeb lub ntiajteb txawj nqus. Raws li cov qauv txheej txheem, qhov ceev ntawm cov dej yog 1 gram ib cubic centimeter, yog li qhov ceev ntawm cov hlau zoo tib yam yog kwv yees li 7.85 grams ib cubic centimeter. Tus nqi no txhais tau hais tias txhua qhov cubic centimeter ntawm steel hlau hnyav kwv yees li 7.85 grams.
Qhov ntom ntawm steel hlau yog qhov tseem ceeb rau nws cov khoom tsim thiab siv. Ua ntej, qhov ceev yog qhov tseem ceeb rau kev suav cov huab hwm coj, ntim, thiab qhov hnyav ntawm cov hlau hlau. Thaum lub sij hawm cov txheej txheem steel hlau ntau lawm, kev tswj ceev ua kom cov khoom zoo thiab kev ua tau zoo. Qhov thib ob, thaum siv cov hlau hlau, kev nkag siab txog nws qhov ntom ntom pab peb xaiv cov ntaub ntawv tsim nyog thiab cov txheej txheem kom tau raws li cov kev xav tau ntawm engineering. Piv txwv li, hauv cov choj, cov tsev, thiab kev tsim tsheb, qhov ceev ntawm cov hlau hlau yog siv los xam nws cov load-cov kabmob muaj peev xwm thiab ruaj khov.
