Piaget's Theory of Conservation: When One Cup of Water is Less Than One Cup of Water
|Areas of Science||
|Time Required||Very Long (1+ months)|
|Prerequisites||You will need to meet one-on-one with at least 15 each of 4-, 5-, 6-, and 7-year-olds.|
|Material Availability||Readily available|
|Cost||Low ($20 - $50)|
AbstractHaving a younger brother or sister can be a real chore. They can get into your things and mess up all your stuff. But have you ever thought that when younger siblings do this kind of thing, they are actually learning about the world around them and how to interact with their environment? Every day, a young child's brain is getting new information about his or her environment and developing ways to organize that information. Learning about and understanding this conduct is the study of human development or of human behavior. In this human behavior science fair project, you will learn about Swiss psychologist Dr. Jean Piaget's four different human developmental stages, and when children learn about numbers and mass.
The objective of this human behavior science fair project is to learn about Piaget's theory of conservation and to investigate when children learn about the equality of numbers and mass.
Michelle Maranowski, PhD, Science Buddies
Cite This PageGeneral citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.
Last edit date: 2020-11-20
Figure 1. A preoperational-stage child exhibiting conservation of mass reasoning.
Have you ever wondered how babies learn? What steps does the human infant take to learn and grow into a logical adult? If you have a younger brother or sister, you might sometimes think that there is no way he or she will ever grow up and become a logical and fully capable adult. But don't worry; most humans do learn how to think logically and symbolically. But how does this happen? How does the human mind grow?
The four stages of cognitive development were described and formalized by the Swiss psychologist Dr. Jean Piaget (pih-YAH-zhay). In the 1920s, Dr. Piaget was working in Paris, developing questions for children's intelligence testing. While working with children, he was struck by the wrong answers that children would give to questions. He realized that the mistakes made by children of a given age were similar. This led him to describe cognitive development as occurring in four stages: the sensorimotor stage, the preoperational stage, the concrete operational stage, and the formal operational stage. Children from birth to 2 years are in the sensorimotor stage. At this age, infants mainly use their senses and motor capabilities to experience and learn about their environment. From about 2 years of age to 6 or 7 years, the child is in the preoperational stage. At this stage, the child starts to use symbols, such as language, to represent objects. For example, a child doesn't need to see a banana to know what a banana is. A preoperational child is still learning from concrete evidence and tends to be egocentric. The concrete operational stage starts at about 6 or 7 years of age and lasts until about age 11 years. Children of this age are thinking logically about concrete events. They grasp concrete analogies and can perform mathematical operations. By age 12 years, children enter the formal operational stage where they can perform abstract reasoning, deduce consequences, and solve hypothetical problems.
It is important to note that human development and the age ranges mentioned above for the various stages of development are not set in stone. People develop at their own rate and all people are faster in some areas and slower in others. This is especially true when children are developing the concept of conservation. This is the principle, which Piaget called the theory of conservation, in which the child realizes that properties of objects—such as mass, volume, and number—remain the same, despite changes in the form of the objects. For example, a young child clamoring for two cookies will be just as happy with one cookie split into two pieces. The type of reasoning that allows the child to see the difference between two cookies and one cookie split in two starts to develop around the age of 6 or 7 years.
In this human behavior science fair project, you will investigate for yourself when conservation of number reasoning and conservation of mass (or substance) reasoning appears in different ages of populations of children. Does a 4-year-old understand that a cup of water is a cup of water, regardless of the size and the shape of the container that holds it? Will a 5-, 6-, or 7-year-old understand this? Will a 4-year-old be able to reason that the number of quarters in a row of five quarters is equivalent to the number of quarters in a wider spaced row of five quarters? Will a 5-, 6-, or 7-year-old understand-this? It's time to round up your younger sibling's friends and find out.
Terms and Concepts
- Sensorimotor stage
- Preoperational stage
- Concrete operational stage
- Formal operational stage
- Theory of conservation
- Who is Jean Piaget and what are his contributions to the field of psychology?
- What are the different stages of cognitive development?
- From your research, can you describe object permanence? When do humans develop the concept of object permanence?
- What is the theory of conservation?
- How is object permanence important for the understanding of conservation?
- What do present-day psychologists think of Piaget's theories of development?
- Myers, David G. Psychology. Fifth Edition. New York: Worth Publishers, 1998. pp. 87-94.
- Boeree, C.G. (2006). Personality Theories: Jean Piaget. Retrieved July 16, 2009.
- Kids Development. (2009). Piaget's Theory of Cognitive Development. Retrieved July 16, 2009.
For help creating graphs, try this website:
- National Center for Education Statistics. (n.d.). Create a Graph. Retrieved July 16, 2009.
Materials and Equipment
- Test subjects; 4-, 5-, 6-, and 7-year-olds (at least 15 of each age). You can find test subjects at your local elementary school. Try to have an even mix of boys and girls for each age group.
- Chairs (2)
- Jug of water, about 1 quart (qt.)
- Food coloring
- Water glasses or tumblers (2)
- Glass of a similar style as the water glasses, except taller and thinner. The level of 1 cup of water in this glass should be at least 1 inch higher than the level of 1 cup of water in the water glass. (1)
- Liquid measuring cup, 2-cup
- Dish towel; note that it might get stained with food coloring
- Quarters (10)
- Lab notebook
- Optional: Graph paper
Conservation of Mass Testing
Since you will be working with human subjects, you need to get advance permission from the children's parents or guardians (and teachers if you are performing the test while they are in school) to make sure that it is alright for the children to participate in the science fair project. There are special considerations when designing an experiment involving human subjects. Intel ISEF-affiliated (International Science and Engineering) fairs often require an Informed Consent Form for every participant who is questioned. Consult the rules and regulations of the science fair that you are entering, prior to performing experiments or surveys. Please refer to the following Science Buddies document for additional important requirements for studies involving human subjects: Scientific Review Committee (SRC).
- Write a clear description of your science fair project, what you are studying, and what you hope to learn. Include how long the child will be tested. Include a paragraph where you get a parent's or guardian's, and/or teacher's signature.
- Print out as many copies as you need for each child you will be surveying.
- Pass them out to the children or to the teachers of the children to give to the parents. You must have permission for each child in order to be able to use them as a test subject.
- Arrange for a quiet place, such as in your school, where you can easily meet with your test subjects, individually. Because there are so many test subjects, you may want to set up several time slots after school or during recess on several days when the test subjects can participate. Each test subject will need to be available for 20 minutes.
- Set up the table and chairs at your location. The chairs should be across from each other. You will first test conservation of mass reasoning.
Add an attractive shade of food coloring to the jug of water. Set up and fill the glasses, as shown in Figure 2. Use the measuring cup to add equal amounts of water from the jug to both of the same-sized water glasses. Also have your dish towel on the table.
Figure 2. Glasses B and C filled.
- Think about what you want to say to the test subjects. You need to say the same thing to each test subject so that the instructions are clear and concise. Write down a script to help you remember.
Invite one of the test subjects to come into the room. Assign him or her a number and record that number, his or her age, and gender in a data table, like the one below, in your lab notebook. Then ask him or her to sit down across from you. Go through your script and explain to the test subject that you are doing a human behavior science fair project and that you would like his or her help. Ask the test subject to look at the glasses in front of him or her. Ask the test subject if he or she thinks that the amount of liquid in the two glasses, glass B and glass C, is the same. Record the test subject's response in your data table.
Test Subject Age Gender Part 1: Are the glasses filled with the same amount of liquid at the beginning of the experiment? Part 2: Which glass has more liquid, A or C? Observations
Now say that you are going to pour the liquid from one of the glasses, glass B, into the other glass, glass A, as shown in Figure 3. Carefully pour all of the liquid from the shorter glass into the taller glass, in front of the test subject. Try to avoid spilling any of the liquid and quickly wipe up any drips or spills with the dish towel. Move glass B to the side and place glass A next to glass C.
Figure 3. Second step in the conservation of mass test.
- Now ask the test subject if he or she thinks that glass A has more liquid, if glass C has more liquid, or if both glasses have the same amount of liquid. Record the test subject's response in your data table. Ask the test subject to explain his or her answer. Your younger test subjects might say "I don't know" and that's ok—record all information in the Observations column of the data table.
Conservation of Number Testing
Now set all of the glasses aside and arrange two rows of quarters in front of the test subject, as shown in Figure 4a, two rows of five quarters each. You are now going to test for conservation of number reasoning. Ask the test subject if he or she believes that the first row has more quarters, the second row has more quarters, or if the rows have the same number of quarters. Record the test subject's response in a data table, like the one shown below, in your lab notebook.
Figure 4. Setup for conservation of numbers testing.
Test Subject Age Gender Part 1: Is the number of quarters the same in both rows at the beginning of the experiment? Part 2: Which row has more quarters? Observations
- Now spread only the second row of quarters out evenly, as shown in Figure 4b, with a couple of inches between each quarter. Once you have spread the quarters out, ask the test subject if the first row has more quarters, if the second row has more quarters, or if the rows have the same number of quarters. Record the test subject's response in the data table in your lab notebook. Ask the test subject to explain his or her decision. Your younger test subjects might say "I don't know" and that's ok—record all answers in the Observations column of the data table.
- The test subject has completed the tests. Thank the test subject for helping you with your human behavior science fair project.
- Repeat steps 3–8 of Conservation of Mass Testing and steps 1–3 of Conservation of Number Testing with each of the test subjects. If necessary, get more water for the conservation of mass test. You can also reuse the water from the previous test. Remember to record all of the data in your lab notebook.
Analyzing the Data
Now that you have collected all of the data, you can start to organize and analyze it.
- Total the number of test subjects in each age group.
- Add together the number of subjects who understood that glasses A and C were equal.
- Calculate the percent of subjects who understood that glasses A and C were equal.
- Add together the number of test subjects that understood that the number of quarters were equal, even after spreading out the second row.
- Calculate the percent of subjects who understood that the number of quarters was equal, even after spreading out the second row.
- Record all of this data in a data table, like the one shown below.
Age Group (years) Total Number of test subjects who understood that glasses A and C were equal Percent of test subjects who understood that glasses A and C were equal Number of test subjects who understood that the number of quarters were equal, even after spreading out the second row Percent of test subjects who understood the number of quarters were equal, even after spreading out the second row 4 5 6 7
- Plot the data. You can do your plots by hand on graph paper, or you can do your plot online. If you would like to do the plot online, or would like to learn more about plotting, try the following website: Create a Graph. Label the x-axis Age Group and the y-axis Percent of Subjects that Understood That Glasses A and C Were Equal. Make a second plot where the x-axis is labeled Age Group and the y-axis is Percent of Subjects that Understood the Rows of Quarters Were Equal, Even After Spreading the Second Row. Are there any trends that you see? When do children develop conservation of mass reasoning? When do children develop conservation of numbers reasoning?
If you like this project, you might enjoy exploring these related careers:
- Do the genders learn at a different pace? Organize your data by age and gender to see if there is an effect. Is the effect of gender minimized by a certain age?
Ask an ExpertThe Ask an Expert Forum is intended to be a place where students can go to find answers to science questions that they have been unable to find using other resources. If you have specific questions about your science fair project or science fair, our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.
Ask an Expert
Looking for more science fun?
Try one of our science activities for quick, anytime science explorations. The perfect thing to liven up a rainy day, school vacation, or moment of boredom.Find an Activity
Explore Our Science Videos
Draw with a Pantograph - STEM Activity
Storm Surge Activity - Protect Houses From Waves
Turn Milk Into Plastic!