Hi,
me again ;o))
I have now to show students that weight is vertical downwards but without speaking of vectors.
The manner suggested in the books is to be seen in the attached file.

On the first two images, the cube in bottom is in modeling clay. First, we make a reference mark on it then we go up the plumbline (maybe with a crank). We burn then the wire (not to make it move) to show that the object will fall to the place located before => we prove that wight is going vertical downwards

In the third one, we just suspend an object with the dynamometer and read the result in newton (maybe here, it'll be fun to have 3 or 4 objects to suspend) => we show that weight is measuring in newton (and not in kg like all students think in France because we use  the word "weight" to express "mass" in common langage ...

Regards,

PS : I asked about my signature but you didn't reply.
How to make it appear ?