The interval and ratio data are very much the same because analogously they both can be ranked, categorized and equivalently have the same space between the values that are adjacent but one thing which sets them apart is that only ratio scales have a true zero.
Example:
One good example of interval data is that if you would measure the temperature of a room, or ice-cold water or any place and the temperature on the thermometer falls below zero degree Celsius as in -10 it will be identified as an interval data. While on the other hand the ratio variables will never descend below 0.