Applied Science - Science and Math (2C) Lab
 OBJECTIVES: Comparing symmetry nature. Describing organisms. VOCABULARY: patterns symmetry MATERIALS: Science and Math (2C) or appropriate materials hand lens Students look at symmetry in nature.
 BACKGROUND: Symmetry is present  in nature.    Symmetry can be considered as an “overall” descriptive term or having an exact correspondence of form  on opposite sides of a dividing line or point.  Humans and most vertebrates are bilaterally symmetrical or one side looks like the other if you image a plane down the center.  All echinoderms have a 5 part pentagonal symmetry It is important to distinguish the overall symmetry and not confuse the surface patterns.   Organisms sometimes have different patterns on different parts of their body.  The picture of the Dalmatian above  is bilaterally symmetrical and there is no pattern of the “dots.” PROCEDURE: Review the meaning of  symmetry.  Symmetry refers to the overall design and looking for similarities across a line or point.      In this lab, students will try to discover different  symmetries by observing different natural things.  At each of the 10 stations, students observe the materials and first decide if the specimen has a particular symmetry. Then they may want to comment if they see some other kind of pattern.     Set up the following stations and have students rotate around to try and discover whether it is radial, cubic, pentagonal, hexagonal or bilateral symmetry.  Some of the materials are in the kit, but others can be easily found to create that station. Bubbles:  Set out some liquid dish detergent and a straw.  Students should slightly dip the straw in the liquid and blow.   Bubbles have radial symmetry.   Sea cookie and sea star (in kit):    All of these organisms have pentagonal symmetry (5 part).  Students may see a pattern of very fine holes throughout the skeleton of the organisms. Mushroom coral (in kit):  This type of coral is solitary, meaning that this one specimen represents one anima.  Many corals are colonial and live in large groups.   This coral has radial symmetry. Snail shells (in kit):  These marine snails do not have any symmetry, but it has a coiled or spiral pattern.  This observation might be hard for students, but noticing the spiral pattern is important.  The pattern is different than a whorl which is coiled on the same plane; a spiral is off centered like a staircase.     Pyrite (in kit):  This mineral has a "cubic" symmetry.  The symmetry can not be determined easily, because it is not continuous.  This is difficult to see unless you have a very good specimen. Leaf (in kit):  Collect a few leaves from outside.  If your classroom has a live plant, it may also be used.  Have students look at the veins in the leaves.  Many have bilateral symmetry as well as a pattern of veins (dendritic). Quartz (in kit):  Has a hexagonal symmetry if the crystal is complete.   Scallop (in kit):  Please note that this is only half of the entire bivalve and it has bilateral symmetry.  The pattern reflects ridges and spines. Slice of Tree:  Notice that it has not perfect radial symmetry.  The rings make up its pattern.