Cov khoom siv uas muab tso rau hauv cov khoom sib tw (blowing agents) yog cov khoom tshwj xeeb uas pab ua cov kab ntsuas hauv cov khoom sib tw li cas nyob rau hauv foam. Cov kab ntsuas no pab ua cov khoom yooj dua thiab pab muab cov kab ntsuas los ntawm kev ua khoom. Ib qho ntawm cov khoom uas muaj cov khoom sib tw no yog: cov khoom siv rau sau khoom, cov khoom siv rau kuab cua, thiab cov khoom siv rau lus qhia. Thaum cov khoom sib tw no tau sib tshuam nrog cov khoom lwm yam, lawv yuav tshuab thiab ua cov khoom sib tw (foam). Qhov kev ua no yog qhov tshwj xeeb rau ntau yam kev ua haujlwm, piv txwv li: kev ua khoom thiab kev kawm. Nyob rau hauv Maijisen, peb xav tias peb yuav muab cov khoom sib tw zoo tshaj plaws rau cov neeg siv khoom, uas yuav pab tau cov neeg siv khoom. Cov khoom ntawm peb pab cov neeg ua haujlwm ua cov khoom sib tw zoo dua, uas muaj kev xav tau thiab muaj kev nyab xeeb. Rau kev paub ntxiv txog cov yam khoom uas peb muab khoom, nrhiav xyuam rau peb Kev tiv thaiv dej tsov txheem.
Kuam txhawb kev xaiv cov khoom uas yuav pab ua qhov tshuaj ntawm qhov tshuaj ntsuab yog qhov tseem ceeb rau cov neeg ua lag luam uas ua qhov tshuaj ntsuab. Nws tuaj yeem sib kub rau qhov kev daws teb thiab qhov kev xav ntawm qhov kev daws teb. Thaum kawg, xyuam xim rau qhov yam tshuaj ntsuab uas koj xav tau. Qhov tshuaj uas pab ua qhov tshuaj ntsuab ib yam tuaj yeem zoo dua rau qhov tshuaj ntsuab tsoo, lwm yam tuaj yeem zoo dua rau qhov tshuaj ntsuab txaus. Ko jat tau qhov tshuaj uas pab ua qhov tshuaj ntsuab ntau dua thiab nce ntau dua yog koj ua qhov tshuaj ntsuab uas nyob hauv qhov tshuaj ntsuab. Piv txwv li, rau qhov tshuaj ntsuab uas siv rau kev kho qhov tshuaj, koj xav tau nws txaus thiab nyob hauv qhov tshuaj ntsuab. Tsis tas li ntawd, rau kev kho qhov tshuaj, koj tuaj yeem xav tau qhov tshuaj uas pab ua qhov tshuaj ntsuab txaus dua kom kho qhov tshuaj. Ntxiv rau ntawd, xyuam xim rau kev siv qhov Antioxidant kom pab ua qhov tshuaj ntsuab zoo dua.