Snails

  The first astronauts on the moon were limited in their explorations by where they could walk. Lunar rovers were first used in the 1970s, and helped astronauts see more of the moon and collect samples to bring back to earth. They could carry one or two astronauts, their equipment, and lunar samples. Now that NASA is considering returning to the moon, more sophisticated rovers with greater travel range are needed.  Firsthand account: It's the early 1970s and an Apollo astronaut is hanging out on the moon with some colleagues. Clad in the requisite bulky space suit, he needs to explore a crater several miles away, so he heads for the rover. He steps up 35 centimeters into the lawn-chair type seat in the center compartment of the aluminum chassis. The rover is about 3 meters long, nearly 2 meters wide, and about 1 meter high. It's roughly the size of a modern Volkswagen Beetle.

Step 1: Present the Problem (and assign tasks) (10 minutes) Step 2: Imagine the Possibilities (look at materials and brainstorm) (3 minutes) Step 3: Develop a Design (build it) (20 minutes) Step 4: Trial 1 (3 minutes) Step 5: Reflect and Revise (10 minutes) Step 6: Trial 2 (3 minutes) Step 7: Lunar Design Engineering Showcase (6-8 minutes) (Each team has about 1 minute)

Snail parts

Snail facts There are thousands of species of snails, including land snails, sea snails, and fresh water snails. The Giant Tiger Land Snail, or the Giant Ghana Snail is the largest land snail in the world and can be up to 12 inches long! Land snails secrete mucus to help them move and reduce the friction against the ground. Snails try to get a diet that is full of calcium to keep their shells strong and healthy. Land snails have microscopic teeth that are contained in rows in a mouth-like structure called the radula. The sea snails breathe with gills and the land snails breathe with lungs, while some species of freshwater snails breathe with lungs and others with gills.

Snail facts Snails are gastropods. Gastro- means stomach and –pod means foot, so the snail’s name means “stomach-foot,” because its stomach is located in its foot! Snails are mollusks. They are invertebrates (no bones) and some mollusks have an exoskeleton (the spiral shell). Snails have two sets of tentacles. One long pair on top of the head contains eye-like structures on the ends. The short pair, located closer to the ground, help the snail feel its way around. These tentacles are retractable – the snail can pull them in when it senses danger. A snail cannot leave its shell. It carries its shell wherever it goes.

Snail vocabulary Mucus Mollusk Calcium Tentacles Microscopic Retract Radula Extend Gills Invertebrate Lungs Spiral Gastropod

Watch these snail videos. (Please preview ahead of time Watch these snail videos! (Please preview ahead of time. Sometimes ads not suitable for children precede these videos.) http://www.youtube.com/watch?v=u4QAnCFd4iw http://www.youtube.com/watch?v=2KjNH2_QDVs

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