The most reasonable response to whether it's appropriate to use the results of the survey to decide where the field trip should be is: No, because the sample is biased toward students who are interested in science.
While 40 students were surveyed, the fact that the survey was sent only to students in the science club means that it may not accurately represent the preferences of the entire student population at Jordan Elementary School. Therefore, the results of this survey may not be a good basis for making a decision for all students.