Answer

Chemicals which potentially could be used for the cooling curve experiment are:
 Stearic acid (mpt 67-72C)
 Phenyl salicylate (Salol)  (mpt 41-43C)
 Paraffin wax - S0001363/500G (mpt 53-57C)
 Palmitic acid - S0001710/100G (mpt 61-62C)
 Oleic acid - S0001244/500ML (mpt 13-14C)
 Lauric acid - S0004895/100G (mpt 43C)
 Napthalene - S4101233/500G (mpt 80 - 82C)
 However, there are some respiratory hazards associated with many of these - check CLEAPSS information first.