Using the markers or chalk, have the child color a rainbow or any other drawing appropriate to the child on the dry erase board/easel.
Use the squirt bottle to squirt the board/rainbow with water, the water causes the marker/chalk to run a.k.a. melt the rainbow.
Note: this activity would work best outside as it can get quite messy.
On a chalk board write the letters of the alphabet with chalk.
Add water to the container and place it next to the chalk board.
Ask the child to dip the paint brush in the water and trace the letters of the alphabet. Alternatively, you can use a sponge to enhance the tactile and grasp skills.
For grading, draw shapes on the chalk board instead of the letters of the alphabet.