Every individual within a species, similar living things potentially able to produce fertile offspring, has traits or observable characteristics that are shared with all other members of that species. One knows immediately that long, floppy ears can belong to a rabbit, donkey or dog, but not to a bird, snake or fish. Pigs have curly tails but chickens and alligators do not. These traits inherited by all members of a species are known as defining traits. Some species display an enormous variety of characteristics and no two living things are exactly alike. It is interesting to note that, according to Sargeant Robert Lillis, Supervisor of the Identification Division of the New Haven Police Department, a fingerprinting expert can almost always detect differences in the fingerprints of identical twins.
A bulletin board in the classroom displaying a group picture, preferably a poster-size enlargement, of the class is an excellent illustration of the physical diversity exhibited by the students. This can be supplemented by individual photographs of the children. Pictures brought in from home depicting the children when younger will illustrate growth and change.
A fingerprinting activity done with the class is a vivid demonstration of the uniqueness of every person. This activity is made even more interesting if preceded by a trip to the identification division of the local police department. The children’s fingerprints can be displayed or kept with data sheets or booklets to be developed.
Detailed data should be accumulated over a period of time on each child. This can begin with obviously observable traits such as eye and hair color and progress to more subtle observable traits such as attached/detached earlobes, cleft chin/smooth chin, ability to roll tongue/ unable to roll tongue, etc. In addition to being recorded on children’s individual record sheets, the data can be displayed on illustrated class charts.
As proficiency with metric measure (the scientific standard) is developed, children can work in pairs and add various body measurements to the accumulated data. All of this data can be used to construct frequency and distribution tables displayed in both bar graph and line graph form.
The graphs can then be used as the basis for word problems dealing with range, mean, median and mode. Word problems can also be formulated using the concepts of ratios and percentages (also expressed in fraction form).
These activities should help to establish cohesiveness within the group and, while pointing out individual differences, establish a wide range of “normalcy”.
Sample lesson plan To be done in two sessions.
To give practice in recording precisely what is observed. To illustrate that the ability to observe and record is influenced by having appropriate measurement tools and vocabulary.
To expand mathematical vocabulary.
To practice using metric rulers.
To introduce protractors.
Materials needed for each pair of students Metric rulers
Pencils or pens and crayons
Simple geometric shapes such as those found in
(see list of resources) or cut from colored paper. If making your own geometric figures, they would include at least two different sizes, 6 inches and 3 inches at the largest dimension works well, and three different colors of each shape such as a triangle, rectangle, square and circle.
Method (first session)
Explain to class that they will be working in pairs and that they are going to be laboratory scientists, recording in as much detail as they possibly can all the information about the figures that will be passed to them. Distribute paper, pencils or pens and one geometric figure to each pair of students. When most children have completed the activity, question to encourage the group to share their written observations. Ask if anyone drew a picture of their figure to include with their written observations. Collect observations.
Pass new paper, crayons, rulers and protractors. Rave children now do new observations and record them. These observations will probably include colored drawings of either the traced or drawn-to-size figures. Do not explain the use of protractors to those children who have not used them before. When children have completed second observation, again have some share what they were now able to record with the rest of the class. Encourage discussion about why the second set of observations are superior to the first. Collect papers and other materials.
Method (second session)
Display a circle from the set of geometric figures used in the previous lesson. Draw a circle on the chalkboard and label the radius and diameter; indicate measurement by writing in actual measurement rather than drawing the figure to size. Leave drawing on the board and do the same for a square. Label sides, indicate measurement and demonstrate the use of a protractor to measure the angles. Repeat with the rectangle labeling width and length. Repeat again with triangle, labeling base and height. Leave all drawings on the chalkboard so children can refer to vocabulary.
Group children in pairs as in previous lesson. Pass geometric figures, two sheets of paper, pens or pencils, rulers, protractors and crayons to each pair. Instruct children to refer to the chalkboard as needed in order to complete a new observation of their figure. Discuss observations when completed. Return observations completed in previous session to students and discuss progression of observations.
Have students write a few paragraphs to tell about what happened to their powers of observation in the course of the two lessons. Display some sets of observations with children’s remarks about lessons.