Consider again, the structure of the water molecule especially the covalent bonds between oxygen and hydrogen. Hydrogen’s single electron being shared with the oxygen leaves hydrogen’s proton (+ charge) sticking out somewhat naked. And the oxygen atom effectively has extra negative charge of hydrogen’s electrons. This results in the water molecule being polar. Like a magnet, it has two poles, the oxygen side being somewhat negative and each of the hydrogens being somewhat positive. With this polarity, the hydrogen of one molecule is attracted to the oxygen of the next to make a weak bond known as a hydrogen bond.
This hydrogen bonding of water molecules is responsible for numerous unique attributes of water and the interactions of water with other substance as depicted in the following video. Watch it with your kids pausing to discuss each of the features at more length.