In a blender, the blades are usually mounted on top of a container that contains the material to be blended. This type of blending is ideal for liquefying foods and for blending hot ingredients, as they can heat up quickly from friction during blending. Food processors have rotating blades inside a housing. The base of the food processor has buttons or controls that allow you to choose between different speeds and pulse action. A food processor typically offers more variety in terms of attachments, such as julienne disks, French fry disks and shredding disks. A blender will do an adequate job mixing most things you would put in a food processor but won’t offer nearly as many options minus needing following along with power cord! For larger families or those who entertain often, a food processor is probably the way to go. For small families or couples, you may want to consider one of each if you will be doing lots of chopping and making pureed soups/sauces/dips.
Blenders are used for making drinks like margaritas or daiquiris. Food processors are generally used to chop up meats, vegetables, and especially potatoes for homemade french fries. However they can be used to make snacks like guacamole or salsa, puree soup ingredients together, mix cake mixes with water and oil etc. etc.
Blenders tend to be smaller and only have a liquid container. This is helpful for making drinks or smoothies on the go. Food processors are generally larger and come with different attachments, such as a slicing blade, shredding blade, etc… A food processor can also chop up foods more finely than a blender.
Blenders tend to liquefy things best whereas food processors can blend but also chop items into pieces before they become liquid. For example, you could put ice in a blender and make a drink that has some liquid but mostly crushed ice. You could not do this with a food processor-you would end up chopping the ice until it became liquid rather than crunchy.
When cooking together the same meal/dish, a blender is usually used to puree items, make sauces or soups, or blend together ingredients. A food processor is used more for cutting/chopping things up, especially larger vegetable chunks or meats into smaller pieces.
Blenders are suitable to create smoothies and milk shakes while food processors are designed mainly for chopping vegetables. Food processors have two blades that cut down on the size of the food being chopped- one moves clockwise and other moving counterclockwise. Blenders only have one blade that spins in one direction which makes them better suited for liquefying fruits and vegetables but not always ideal at breaking them down completely before turning it to liquid form.
Food processors are electric devices with additional set of interchangeable / attachable blades to cut vegetables and fruits. Blenders, on the other hand, are manually operated and consist of a blending jar and a blade at its base which is used to blend food items. Food processors can be used for chopping or pureeing dishes whereas blenders are mostly used for smoothies.