Turn a handful of yarn into a hangable heart ornament using cornstarch glue.
You can store cornstarch glue in the refrigerator for up to a week. If the mixture gets too gel-like, stir in ¼ cup of hot water.
First, make the glue by combining ¼ cup of cornstarch and ½ cup of water in a saucepan and stirring until smooth.
Heat the mixture over medium heat until it's thick and translucent. Allow it to cool to the touch.
Cut yarn into foot-long pieces.
Place a heart-shaped cookie cutter on the shiny side of a piece of parchment paper. Have your child push a piece of yarn into the glue to coat it. Pick up the piece and run it between a thumb and forefinger to remove the excess glue. Lay the yarn inside the cookie cutter.
Repeat with the other pieces until the yarn fills the heart shape in a thin layer. With clean hands, press the yarn flat. Gently lift off the cookie cutter and allow the yarn to dry hard, at least a day.
You can speed up the drying process by placing the hearts and parchment paper into an oven set to "warm" for an hour or two.