Estimated time to make this valentine:
2 half-hour sessions

Appropriate age group(s):
Preschool and Younger
Elementary School
Middle School

Materials:
self-hardening clay
water
rolling pin
heart-shaped cookie cutter
water-based acrylic paint
beads/shells
popsicle sticks
plastic knives

Instructions:
For younger children:

1. Take some clay and have fun exploring the texture and coolness of the clay (note: you may need to add extra water for smaller hands to make the clay softer).
2. Roll the clay into a ball.
3. With your rolling pin (that has been designated for non-cooking projects), roll out the ball into a flat pancake.
4. Take your heart-shaped cookie cutter and cut hearts into the clay; add beads, shells, etc. (optional).
5. Let clay harden for a day.
6. Paint your hearts with water-based acrylic paint.

For older children:

1. Take some clay and create a variety of shapes and sizes of hearts by first kneading the clay (to soften it). Roll out the clay with the rolling pin, using the cookie cutters or popsicle sticks to create heart shapes in the clay or manipulate the clay by molding it into the heart shape (without first rolling it out). Try to create a shape that is more three-dimensional when molding the clay.
2. Use the popsicle stick to help define contours and grooves.
3. Design a pattern into the heart with a plastic knife.
4. Let clay harden for a day.
5. Paint your hearts with water-based acrylic paint.

Other comments or suggestions to consider:
Give the heart a long shelf life and shellac it!