Which of these is a mixture of a solid that is soluble in water and a solid that is insoluble in water?
a) iron and steel
b) salt and sugar
c) iron and gravel
d) gravel and sugar

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this