Secular Trend

The purpose of this project is to examine the secular trend in the age and other characteristics of puberty in families. Ask your parents and grandparents the age at which each went through puberty (parents should give information on grandparents, if information is not available from grandparents directly). Older students may have mature children that can be included in this chart. Record the age at which you went through puberty, using the data sheet that follows and then answer the questions.

DATA SHEET

Record age of puberty for:

Self Mother _____

Father _____

Maternal:

Grandmother _____

Grandfather _____

Paternal:

Grandmother _____

Grandfather _____

Questions

1. Does the age of onset of puberty differ for the three different generations represented in the data? If so, in what way?

2. Does the age of onset of puberty differ for the two sexes? What is the direction of the difference?

3. How do the findings on generational differences relate to the trends described in the text? Why might they be similar or different from the findings described in the text?

4. How do the findings here on sex differences on age of puberty relate to data in the text?

Research Project 2 Piaget’s Pendulum Problem

Pair up with a classmate. One of you is to present the other with Piaget's pendulum task. Then reverse roles and one of you will present the other with Piaget’s chemical task. Then test an 11-year-old on the two tasks.

For the pendulum task, provide a frame for a pendulum as well as various lengths of string and a number of weights of equal size, Instruct your subjects to assemble the pendulum and to identify the variable(s) that determine the period of the pendulum swing. The possible variables to manipulate are length, weight, height of the drop, and force of the initial push. Record on the data sheet the variables that the subjects manipulate and the way in which subjects organize the manipulations.

For the chemical task, provide water, hydrogen peroxide, potassium iodine, acid, and thiosulfate in five numbered flasks. All of the chemicals are initially clear liquids. The subjects must determine which combination of chemicals produces a mixture with the color yellow. Record on the data sheet the variables that the subjects manipulate and the way in which subjects organize the manipulations.

Both tasks present combination problems, which are solved by systematically manipulating each of the variables and all of the possible combinations of variables to identify the correct solution. These tasks test for aspects of formal operational reasoning. After making the observations, answer the questions that follow.

DATA SHEET

Task Subject 1 Subject 2

Sex____Age___ Sex___ Age ___

Pendulum Task

Chemical Task

Questions

1. How did the students solve the tasks? How would you characterize the responses? Did the students systematically manipulate the variables?

2. How did the 11-year-old solve the tasks? How would you characterize the 11-year-old’s responses? Did he or she systematically manipulate the variables?

3. What differences did you observe in performance of the younger and older adolescent? How would you characterize their performances according to Piaget's theory? Did you find evidence of formal operational reasoning in either, both, or neither of your subjects? How would you account for your findings? What is the nature of the difference between performances of the younger and older adolescent?

Chapter 13