In Pre-School the children have been developing their fine motor skills using the bottle sprays to squeeze the handle to water the painted flowers. The children are building  muscle strength in their fingers through fine motor skill activities that offer a wealth of benefits, particularly in the development of writing:

Stronger finger muscles, especially the thumb, index, and middle fingers (used in the tripod grip), allow for a more controlled and comfortable hold on the pencil. This reduces fatigue and improves dexterity.
Increased strength enables more precise movements of the fingers, which are essential for forming letters accurately, neatly, and with appropriate pressure.

These activities build finger strength often also improve the ability to move the fingers independently and in coordination (in-hand manipulation), which is vital for adjusting the pencil within the hand without losing contact with the paper.