A water marble nail is when nail polish is dropped into a cup of water, creating a swirl pattern, and then the nail is dipped into the cup so that the pattern wraps around the nail.
To do this, you first need a cup of room temperature water. Then, you need to choose the colors of nail polish you want to use. You drop one drop of the first color into the cup of water, and it will spread out. Then you drop a drop of the second color into the center of the first color, and it will push out the first color, creating a ring effect. You keep doing this with each color you want to use, adding each drop into the center of the previous drop until there are multiple rings of colors in the cup.
Once you have the colors in the cup, you can use a toothpick or a pin to make a design on the surface of the water. This will create swirls and patterns in the colors. You want to make sure not to mix the colors too much, or you will ruin the design.
Finally, you dip your fingernail into the cup and hold it underwater for a few seconds. This will transfer the pattern onto your nail. You then need to remove your finger from the water and clean up any excess nail polish that may be on your skin.
Overall, water marble nails can be a fun way to add a unique design to your nails, but they do require some patience and practice to get the technique just right.