Deicers work by exhibiting one of two thermal reactions: exothermic or endothermic. Exothermic materials, such as sodium ...
Exothermic ice-melt compounds, such as calcium chloride and magnesium chloride, are more effective in subzero temperatures ...
Birds need water in winter so it's okay to still fill your birdbath. But if you're considering using chemicals to keep the water from freezing, think again.