One eight-ounce cup of ice contributes how many milliliters after accounting for melt?

• A. 60 mL
• B. 120 mL
• C. 180 mL
• D. 240 mL

Answer: (B)

The key idea is that melting conserves mass but changes volume because ice is less dense than liquid water. An eight-ounce cup filled with ice holds about 240 milliliters of ice by volume. Ice has a density of roughly 0.92 g/mL, so that ice mass is about 240 × 0.92 ≈ 221 g. When it melts, that mass becomes water with a density of about 1 g/mL, so the melted water volume is about 221 mL. So you’d get roughly 220 mL of water after the ice melts, since the melted water volume is a bit less than the original ice volume due to the density difference.