This short activity can be done using any classroom books of which you have 5 per group. The main point of discussion after the activity is the real world application and assessment of "work." Is it actually the same amount of perceived work to lift one book five times as it is to lift all five at once? What if five books were too heavy to lift?
This is another activity that lends itself to being repeated at home with your student's family. This way they can reinforce the concepts through teaching.
If you have standard spring scales that are calibrated in both grams and Newtons, measure the books in Newtons, multiply that times the distance lifted, and your units for work will be in Newton Meters (Nm). If you can only weigh the books, then you will be multiplying the weight in Kg times 10 meters per second per second (the acceleration due to gravity) to get Newtons, and then multiply that times the distance lifted. You get the same value and units either way. NB the acceleration due to gravity is 9.8 m/s2, but rounding to 10 works fine and seems to be the conversion on the spring scales.
To weigh the books with a spring scale, I simply put a piece of tape across the spine and then lifted the book with the scale that way.
I have included both PDF and Word files, so you can use this as it is or alter it to suit your needs.