What is the difference between Vector, Scalar and Tensor quantities in Physics.
In: Physics
Scalar quantities effectively just numbers or magnitudes. 1, pi, 237 are all scalar quantities. A vector describes something which has both a magnitude and a direction like a velocity or force. (1,1,1) , (2,4), (0,0,0) are all vectors. A tensor is generalizing the idea of a vector into N dimensions, in the simple case you can think of stacking N-1 dimensional tensors.
To get a vector (1st order tensor) you’re taking some number of scalar quantities (0th order tensor) and writing them out in a column. If you take some number of vectors and write them out as columns to get a rectangle of numbers you get a matrix (2nd order tensor*), if you take matrices and stack them together to form a cube of numbers you get a 3rd order tensor*, you can keep doing this for any number of dimensions.
*This is a simplified explanation and not the actual definition of tensors, not all 2d matrices are 2nd order tensors.
Scalar is a number, a scalar with direction is vector. I don’t think I can do a ELI5 for tensors.
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