Physics for Sonography: The Prerequisite That Sets It Apart- almost every allied-health field shares a science core of anatomy, physiology, and math. Sonography adds one requirement that the others usually don’t: physics. The physics requirement for sonography is the prerequisite that defines the field, the one applicants most often scramble to find, and the foundation of the credentialing exam every sonographer must pass. This guide explains why physics is required, what the course needs to cover, the recency and grade rules, and how to complete it. For the full list of requirements, see the complete sonography prerequisites guide.
Ultrasound imaging is applied acoustics. Every image a sonographer produces depends on how sound waves propagate, reflect, attenuate, and return through tissue, and on how the machine’s settings shape that signal. You cannot optimize an image — or recognize an artifact — without understanding the underlying physics. That is why programs require a college physics foundation before you ever touch a transducer, and why the credentialing path makes physics non-negotiable.
The connection is formalized in the credential itself: the ARDMS requires candidates to pass the Sonography Principles & Instrumentation (SPI) exam, which is essentially an ultrasound-physics and instrumentation exam, in addition to a specialty exam. Your prerequisite physics course is the on-ramp to that exam.
Programs typically require one or two semesters of college physics with a lab, covering the topics that map directly to ultrasound:
Some programs accept a single introductory physics course; others require a two-course sequence to cover all of these topics. A lab component is almost always required, and many programs will not accept a lecture-only physics course.
| Field | Physics requirement |
|---|---|
| Diagnostic Medical Sonography | Required — central to imaging and the SPI exam |
| Respiratory Therapy | Usually only for bachelor’s (BSRC) programs |
| Nursing | Not typically required |
| Radiologic Technology | Radiologic physics usually taught inside the program |
This is the practical reason flexible online physics is hard to find: most allied-health applicants never need it, so general-education catalogs and self-paced providers rarely prioritize it. For sonography applicants, that scarcity makes physics the prerequisite worth locking down first.
Read each target program’s requirement carefully. If a program lists a single introductory physics course, one term with a lab may satisfy it. If it requires coverage of acoustics, wave motion, heat, electricity, force, and energy, a two-course sequence is often needed to cover the full range. When in doubt, completing the sequence keeps every program on your list open rather than discovering a gap after you apply.
Physics is a science prerequisite, so it falls under the same recency scrutiny as anatomy and physiology — commonly a five-to-seven-year window, with competitive programs often enforcing five. Most programs require a grade of C or better, and because physics feeds the science/math GPA that programs rank on, a strong grade does double duty. If your physics is old or below the bar, plan to retake it — see retaking prerequisites for sonography school.
Because campus physics sections are often full or offered only once a year, a self-paced, online, accredited physics course with a lab is frequently the fastest way to clear this requirement. We cover the online route in detail in physics for sonography school online (with lab). The courses are Physics I (PHY 115) and Physics II (PHY 116); pair them with College Algebra (MATH 107) if you still need the math foundation that physics builds on.
Confirm the course satisfies your program. Physics requirements and accepted course formats vary by program. Before enrolling, confirm with the registrar that a regionally accredited online physics course with a lab will count, and check whether one course or a two-course sequence is required.
Ultrasound imaging is applied acoustics, so you need a physics foundation to optimize images and recognize artifacts. The ARDMS SPI exam is also physics-based, making physics central to both school and credentialing.
Usually one or two semesters of college physics with a lab, covering wave motion, acoustics, energy, and electricity. Some programs accept one course; others require a two-course sequence.
Almost always. Many sonography programs will not accept a lecture-only physics course, so choose one with a recognized lab component.
Yes — as a science prerequisite, physics commonly expires after about five to seven years, with competitive programs often enforcing five. Check your program’s recency rule.
Yes, when it is from a regionally accredited institution, includes a lab, and posts to an official transcript. Confirm acceptance with your target program.
Continue with physics for sonography school online (with lab), the complete sonography prerequisites guide, and how to get into a competitive sonography program.
