Is a mouse hardware?
Yes, a mouse is hardware.
Think of hardware as the parts you could physically touch,
inside or outside of the computer. You could touch a mouse. So what
can you touch? A keyboard, a hard drive, a monitor... Those are all
physical things that you can hold in your hands, so they are all
hardware.
Software are the parts you couldn't touch. They are the codes,
programs, apps, and data, the parts that "think" to tell the
computer what to do.