MS 224 in the Bronx is known as the Science School for Exploration and Discovery. Ironically, however, it has neither a science lab nor lab equipment. As a substitute for year-round lab experiments, students had one class period aboard the BioBus, a refurbished bus loaded with high-end science equipment to whet their appetites for what science is really about. The ­science lab on wheels paid a daylong visit to the school on Dec. 18. Two classes from the 6th, 7th and 8th grades each had time in the lab. Science teacher and Chapter Leader Rashad Brown said his 6th-grade classes were excited and he anticipated the experience would ignite a heightened interest in science. In the lead-up to this semester’s study of cells, his students had a chance to get a close look through high-powered microscopes at daphnia, a shrimp-like animal found in ponds. The samples they studied were from the Bronx River. The children also examined their own cells after swiping inside their cheeks with a Q-tip. Created by a nonprofit organization in 2008, the BioBus has its own science teachers aboard. A visit by the BioBus is essentially a field trip that comes to the school and provides preparatory and follow-up lessons and can be booked through its website at www.biobus.org/education. Brown said the school has been seeking funds for a science lab and equipment for 11 years. He hopes a request submitted recently to State Assemblywoman Carmen Arroyo will prove successful.