Cardboard tubes make convenient stamps--just not always heart-shaped.
Art Project: Stamping "hearts" with t.p. tubes
Clean, empty toilet paper tubes
paint (we used red and white)
small paper plates
masking tape (optional, but helps hold the t.p. tube in a heart shape if that's what you want)
Penguin and Pinecone : a friendship story / Yoon, Salina
Project inspired by this photo
What Kids Do: A few actually tried stamping hearts
Or... just their fingernails:
Hindsight Tip: If you REALLY care about these stamps being heart-shaped, I'd recommend shaping the tubes yourself before class and securing them with a piece of the masking tape. Otherwise, it's tricky (even for adult hands) to hold it in exactly the right shape as you're stamping with it.
Variations to try:Try this as a study in shapes. Can you make a square stamp with a t.p. tube? An oval? A circle? What other shapes can you make?
Adult Challenge: Allow your child to experiment and "fail." If they're not doing the project as I suggested, but they're also not hurting anyone or any property, just let them make their own discoveries!