Bending Balsa Wood What Is The Best Way To Make Balsa Wood Pliable But Not Making It Weaker?

What is the best way to make balsa wood pliable but not making it weaker? - bending balsa wood

I'm doing a science project where I try different models of the bridge out of balsa wood. I think that the strengthening of arch bridges, but I fear that if you bend balsa, they are weaker. I learned that water or steam, the wood is flexible. What is the best way to balsa flexible?