Physical properties are those that you can observe with your 5 senses.

Chemical properties can only be observed when something is reacting with another substance.

So, let’s say that we pick an object like a sheet of paper.

Paper would be solid, whatever color it is is also a physical property, it has a certain mass, it has a certain density. All of these are physical properties.

A chemical property would be the paper’s flammability. You wouldn’t be able to observe this unless the paper was reacting with oxygen (burning).

For salt and sugar. Physical properties. They are both white, they are both soluble in water, they are both solids and are crystalline. However, they have different melting points and different densities.

Chemical properties, sugar can burn, salt cannot. They also have a different chemical composition.

I personally would use either taste, density, or melting point to distinguish between the two. You can melt sugar using a hot plate or Bunsen burner. You cannot do that with salt (its melting point is too high).