Answer:
Explanation:
They could have conducted the experiment at least thrice for each sample (sand and water) OR done the experiment once but at least in triplicates (i.e obtained six identical 1000 ml beakers; with three beakers for each sample, all ran at once). Also, the same volume of sand put in three of these beakers should be the same volume of water put in the remaining three beakers as rightfully done in the experiment.
The essence of conducting the experiment at least thrice for each sample (sand and water) or done the experiment once but at least in triplicates is to be able to subject there recorded data to statistical analysis; this affords them the opportunity to remove/reduce all forms of error the experiment could have been exposed to during the course of the experiment.
Possible errors include (but not limited to) error due to parallax while taking the volumetric measurements and timing errors.
