Vivekanand Vellanki
A scalar is something that has only a magnitude. Examples include 10 mins, and 100 meters. A vector is something that has both magnitude and direction. Example: 100 meters heading north. Let me explain the same differently: Are +1 and -1 the same? Well, both are at a distance of 1 from 0. But, they are different because one is positive and the other is negative. Draw a circle of radius 1cm on a paper. Draw a few radii in this circle. Are all these radii the same? They are all of length 1. As a scalar, they are all the same. However, we know that they are all different because they go in different directions - as a vector, they are all different. The same applies to vector quantities like velocity. Velocity is the vector counterpart of speed (a scalar quantity).
Daniela Arias Toscano
A scalar is simply a quantity while a vector is also a quantity but it has a given direction. For example, speed is a scalar while velocity is a vector.