Yeah, SEP is very useful but can have a slightly awkward perspective on these sorts of things. I intuitively think of physicalism as "That which is real is that which can be brought to the attention of the senses (directly or indirectly)". You need various caveats and elaborations to account for hallucinations and the like, but that's the basic idea I have in my head.

Hmm, then this definition of physical would also include traditional notions of deity, spirits and soul, since all are thought of as having indirect sensible effects.

You raise a good point. Cultural superstition is just the sort of thing that requires elaborations to the definition. It's much like the problem of demarcating science from pseudoscience.

Popper's attempted solution was to say that implicit in "brought to the attention of the senses" is a requirement that one's physical model generates falsifiable predictions of future observations. Thus astrology cannot be said to be part of a physicalist worldview, since horoscopes are so open to interpretation that they cannot be falsified.

That said, some notions of deities could be said to be physical, for example the proposition that there is a skygod who will make it rain if you say a certain prayer. This is not unphysical in this sense; it's just wrong. What would make it unphysical if you started moving the goalposts arbitrarily, for example "oh, it will cause rain next year instead" or "oh, you just weren't praying with true belief in your heart".

So, if someone created a falsifiable model of the soul that produced sensory interactions, would that mean the soul is physical?

In my mind this demonstrates 'physical' is not very well defined by physicalism, since souls etc. are considered to be non-physical, yet could in theory meet the requirements of physicalism.

Well, if someone produced such a model then they probably wouldn't be talking about the same soul as, say, the Christian soul.

Also the word "physical" has a different usage amongst philosophers than amongst laymen. In philosophy, a thought or idea might be thought of as physical since it is a property or pattern of neurological activity, but the average person would not say a thought was physical.