PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Flight Instructor; Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 140; Flight Crew Total 540; Flight Crew Type 315
Conflict NMAC; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Human Factors; Airspace Structure
I was conducting take off and landing practice with a student; staying in the traffic pattern at ZZZ. At approximately 500 AGL; on short final for 17R my student was flying when I noticed a Cessna at our altitude on a collision course. At the same time the TCAS reported the traffic and I took controls to emergency descend below the traffic. At that time ZZZ Tower reported traffic alert and that he was unaware of where that traffic was going. I completed a normal landing and ended the training flight.
PA28 flight instructor reported a NMAC with a Cessna on short final.