Why do students rush to complete an assignment?

This morning I gave a class to chemical engineering students on the basics of the literature resources of their field.  The powerpoints are found on this Libguide http://researchguides.njit.edu/che396 .  I discussed the basics of searching Scifinder Scholar and Scopus.  Several times I mentioned that it takes the database only a few seconds to execute a search and display an answer set.  It takes more time for the researcher to evaluate the retrieved references since very often the search term are in the bibliographic record or abstract, but not in the desired relationship.  The students received training passwords and had to find 5 references on one of these topics:


Liquid hold-up in packed columns (or towers) for any of the following packing types: Jaeger rings, tri-packs, Novalox saddles, pall rings


Heat transfer coefficients for a flat plate exchanger


A model for particle elutriation from a fluidized bed of particles


Model for rotary kiln drier (dryer)

I told the students the training passwords expired at the end of the day.  I suggested they do the search while they had the training password and to evaluate the results later. The students were give one week to complete this assignment, but half the class turned in their assignment within 30 minutes.  Why did they rush?

1.  The assignment was too easy and they felt they had picked the 5 most relevant articles.
2.  They were not interested in literature searching and just wanted to get it finished ASAP

My concern was in either event, their expose to literature searching was just too brief.  It is my hope that the student will know when and how to use Scifinder Scholar in the future.

I will have to compare the grades of students who submitted the assignment quicky versus those who took their time with it.