Showing beginners how to forge can be tricky with kids around. I read a blog post where a smith starts by shaping cold metal to explain the basics. This way, the child sees how metal moves before adding heat and flame. Let them try hitting a cold copper piece with a hammer, so they feel the work involved. Make sure everyone stands back when you light the forge, and talk through each step. In my view, that kind of slow demo makes the magic real without any scary moments.
Actually, when my niece wanted to see forging, we started with aluminum cans. Squashing them with a mallet showed how metal changes shape without the heat. Then we moved to heating a piece of steel rod, and I let her dip it in water to see the steam and color change. She was fascinated by the sparks when we hit the hot metal, but we kept a safe distance and used long tongs.