Each institution should have an Institutional Review Board (IRB) or a Human Subjects Review Board (HSRB). Any experiment involving human subjects must be approved by this board before any data can be collected.
If each group of students submit actual IRB proposals, it is expected that the time lines in the labs will need to be extended. Depending on your institution, IRB approval can take up to several months.
It may be most appropriate to receive a general approval for each lab involving human subjects in your course well before the experiment is conducted. Then each group of students would not need to submit individual IRB proposals and wait for approval. Institutions may provide a general approval of a lab to be used in a course provided:
If your institution does not have an Institutional Review Board, you can find more information on registration as well as educational materials here