Burnin' Ants

There aren't any ants left outside but there are several dead leaves.  We are using convex lenses to burn holes in leaves and watch the smoke rise.  Convex lenses have a focal point and the students can use it to focus the sunlight on a leaf.  They also get to play with concave lenses to see how the image looks.
The start up for today is "What kind of mirror makes a bigger image?"