（214? Huai 'an) In the process of selecting a spring dynamometer, Xiao Ming found that when measuring the same force, he used dynamometer with different specifications, and the spring was elongated.

(1) Keep the spring material and thickness the same, but the original length is different, and change the magnitude of the tension and compare the magnitude of the elongation, which is to explore the relationship between the elongation and the original length of the spring, so it is a research conjecture 2;

(2) In the experimental scheme, "one spring is cut into two pieces with different lengths", which keeps the same spring material and thickness, but different original lengths;

(3) In the experimental scheme, "stretch the spring with the same force" to observe the change of elongation and explore the relationship between elongation and pulling force;

(4) The physical quantity to be explored in this inquiry process is the original length of the spring, and the elongation of the spring is compared.

So the answer is:

(1) 2; (2) two springs with the same material and thickness are obtained;

(3) the pulling force;

(4) the original length of the spring; The corresponding elongation.