1. Color: The visual appearance of a substance, determined by the wavelengths of light it reflects.

2. Shape: The form or outline of an object, which can be fixed (for solids) or fluid (for liquids and gases).

3. Texture: The feel of a substance, determined by the arrangement and size of its particles (e.g., smooth, rough, bumpy).

4. Density: The amount of mass per unit volume of a substance. This can be observed by comparing how easily an object sinks or floats in a liquid.

5. Boiling Point: The temperature at which a substance changes from a liquid to a gas. This can be observed by heating the substance and noting the temperature at which it starts to boil.