Why are there Dry and Liquid Measuring Cups? What's the difference?

I am going out on a limb here and estimating that at least 4 out of every 10 homes now only has 1 set of measuring cups.  And this one set is used to measure

When is a Cup Not a Cup? - Learning to Measure with Rhonda Sue's

Economical Elegance Why are there Dry and Liquid Measuring Cups? What's the difference?, dry ingredient measuring cups

Dry Vs. Liquid Measuring Cups: Here's What You Need To Know

Why Do We Need Liquid and Dry Measuring Cups?

Dry versus Liquid Measuring Cups

How Many Ounces In A Cup (Free Printable Chart) - Food Lovin Family

Quality at a Steal Why are there Dry and Liquid Measuring Cups? What's the difference?, dry ingredient measuring cups

Dry versus Liquid Measuring Cups

Dry Vs Liquid Measuring Cup