The disc also has short movies about the different types of bacteria, the nature of the protozoa in a drop of pond water, spore formation, and the properties of living cells. Better yet, students can find a multitude of different single-cell plants and animals in a sample of pond water. You can collect color sketches of student discoveries and create a class zoo by posting them on a bulletin board. Students will always find inanimate particles of one kind or another in their pond droplets and sketch them too. By studying the characteristics of life on Earth, students can make more informed judgments about the possibility of life on Mars.
Life is tenacious.
Instead of using the version of this activity in the Universe at Your Fingertips activity manual, in which students construct a model out of cardboard, Styrofoam, and other materials, I ask my students to design and draw their aliens on paper. Then they describe the special adaptive features of their aliens orally to the rest of the class. After this activity, you and your students can discuss the possibility that their martian aliens actually exist somewhere on or below the surface of present-day Mars. I hesitate to report that the ratios on all three faces are almost identical. It is human nature to feel the thrill of the hunt, the stalking of the prey.