Use chemical colorants to make the flame turn different colors. Barium will produce a light green flame; calcium turns a fire brick red; copper creates a blue-green tinge; Lead will turn the fire blue-white; use potassium for lilac color and sodium for bright orange.
Have an adult work with children in finding and handling these chemicals.
Find everyday household items that contain these chemical elements. Some examples of these are newspapers and magazines. Keep in mind that these do not always work, so you might have to actually purchase the elements in a powder form from a science store.
Mix the powder chemical with water or alcohol and soak the mixture into logs, pine cones, or sawdust.