What are software objects made out of?
Computer memory.
It is only a slight exaggeration to say that memory (both main memory and secondary memory) is what a computer is about. The rest of the electronics — the processor chip, the buses, the power supply, the keyboard, the video card and so on — exist only to work on memory and to show what it contains. So what else could a software object be but a block of memory?
(Actually, it is not quite correct to claim that a software object is a block of memory. A software object is somewhat like a bank account — its existence is spread out and does not correspond one-to-one with any particular piece of material. But for now it is convenient and reasonably accurate to think of a software object as a chunk of memory.)
Objects (real world and software) have identity, state, and behavior.
Software objects have identity. Each is a distinct block of memory. (Just like a yellow tennis ball, each software object is a distinct individual even though it may look nearly the same as other objects of the same type.)
Software objects have state. Some of the memory that makes up a software object is used for variables which contain values. These values are the state of the object.
Software objects have behavior. Some of the memory that makes up a software object contains programs (called methods) that enable the object to "do things". The object does something when one of its method runs.
(Review) What is the defining characteristic of the type of computer called a von Neumann computer (the type of nearly all current computers)?