Use magnets of unequal strength
Put one magnet on one side and two magnets on the other or find a set of magnets with un equal strength.
The difference in the strength of the magnets represents the difference in the the electro negativity of Hydrogen and Oxygen.
The weaker or fewer magnets representing the Hydrogen atom and the stronger magnet representing the Oxygen atom.
Place the magnets under a clear sheet of plastic facing one another
North to North or South to South. Then sprinkle iron fillings unto the plastic.
The iron fillings will represent the location of the electron density in the bond between the Hydrogen and Oxygen atoms.
There will be many more iron fillings around the stronger magnet representing the Oxygen atom. There will be fewer iron filling near the weaker magnet representing the Hydrogen
The strength of the magnets is an analogous to the strength of the pull ( electro negativity) of the atoms for electrons. The density of the iron fillings is an analogy for the distribution of electron density in the bond between Hydrogen and Oxygen. The picture formed by the magnets and iron fillings is an analogy to the unequal sharing of electrons in a water molecule.
Here's an analogy I found online.
I claim no originality for it.
I come to class with a big chocolate chip cookie.
I tell you that I am going to share my cookie with you.
You think that I will break the cookie in half and share the pieces equally.
However, I break off a little piece for you and keep most of it for myself!
I did share. I just didn’t share equally!