1. Iron: Iron is much denser than water, making it sink.

2. Rock: Most rocks are denser than water, especially those made of materials like granite or basalt.

3. Sand: While individual grains of sand might float, a pile of sand will sink because it's denser than water.

4. Steel: Steel is an alloy of iron and other elements, making it even denser than pure iron, and thus, it sinks.

5. Coins: Most coins are made from metals like copper, nickel, or silver, which are all denser than water.