Assertion: helium balloon | /r/HasProperty | mylar
Facets:
Source sentences:
text: Helium balloons are Mylar and not rubber because there is less space between the molecules in Mylar, so the balloon stays inflated longer.
text: Why Helium Balloons Are Foil or Mylar
text: So, helium balloons are thin foil or Mylar because these balloons hold their shape without the need for a lot of pressure and because the pores between the molecules are smaller.