Question 1132081
Nominal, no rank order
example--different types of automobiles

ordinal--rank order, but it isn't linear, so that liking something on 1-4 scale, a 4 is not 4 times as much as a 1, but it clearly is better than a 1.  Surveys ranking something on a 1 to 4 scale

interval--the spaces between measurements are equal, but not necessarily linear. 
20 degrees is greater than 19 by one and less than 21 by one, and the difference in heating is equal from 19 to 20 to 21.  BUT, 20 degrees is not twice as warm as 10 degrees, unless one uses the Kelvin scale, which other than physicists, meteorologists, chemists, few deal with.

ratio--interval data with a clear zero point. Twenty is twice as much as ten, and the spacing is the same.  

Does it matter?  Yes.  A like of 2.5 on a 4 scale doesn't say whether half were 1 and half were 4 or exactly how they were distributed.  Manipulating those numbers as if they were ratio data is commonly done, but it is not clear what it means.