Quantitative and Qualitative Observations

 

Objectives: After completing the lesson, students will be able to:

 

Key Question: "How do scientists describe the world we live in?"

 

Overview:

Students are asked to draw and describe a familiar object (a penny) from memory. This leads to an introduction of how a scientific experiment is performed, through an initial exploration of the unique properties of water. The student is required to make a hypothesis, and record quantitative and qualitative data in an organized manner. The lesson ends with an examination of the importance of observation in science, and the difference between an observation and an inference.

 

Time Required: 1-2 class sessions.

 

Materials:

 

Procedure:

Part A: (optional)

  1. Have students use a compass to construct two large circles in the center of an unlined sheet of paper. Elsewhere on the same sheet of paper, have each student use the compass to construct a circle that they feel is the exact diameter of a penny.
  2. In the 2 large circles, have students draw the observe and reverse sides of a Lincoln head penny, from memory.
  3. Off to the side, have each student write a list of things they are "sure" are on a penny, also from memory (e.g., "E. Pluribus Unum," bust of Lincoln facing left or right).
  4. After a class discussion of what a penny looks like, hand each student a penny to compare to their drawings and lists.

 

            Part B:

  1. Distribute a copy of the "Water on a Coin" handout to each student. Allow time for each student to read the "Background" section. Answer any questions.
  2. Have the resource monitors in each group collect the needed materials for the experiment, "Water on a Coin." Allow time for each group to review the procedure for this experiment, make hypotheses, and perform the experiment as a group.
  3. Have the students answer the "Questions/Conclusions" at the end of the handout. Discuss their answers with the class.

 

Assessment: complete p. 7 of Inquiry Skills Activity Book.

 

Suggestions for Homework:

 

OUSD Science Content Standards (State of  California Science Content Standards):

1-a through f, except c ( 7-a through e).

 

References:

Bell, J.L. Soap Science. Reading, MA.: Addison-Wesley Publishing Company, 1993, p. 5.

 

Focus on Earth Science: Laboratory Manual. Upper Saddle River, New Jersey: Prentice-Hall Inc., 2001, pp. 45-48.

 

Inquiry Skills Activity Book. Upper Saddle River, New Jersey: Prentice-Hall, Inc., 2001, pp. 5-8.

 

Project Earth Science: Physical Oceanography. Arlington, VA.: National Science Teachers Association, 1995, pp. 15-21.

 

Notes:

            Though not listed in the "Materials" section, it is a good idea to use some type of tablecloth or paper to cover the group tables. It is also a good idea to have sponges, rags, paper towels, and wash tubs on hand, in case of spillage. This is a good activity to emphasis safe laboratory procedures and the necessity to work as a group to avoid accidents.

 

Alternative Lesson:

 

Key Vocabulary:

 

atom: the smallest part of an element that can exist. It consists of a nucleus of protons and neutrons, surrounded by orbiting electrons.

 

element: a substance that cannot be broken down into more simple substances by chemical reactions.

 

hypothesis: prediction about the outcome of an experiment or observation.

 

molecule: the smallest unit of an element or compound. A molecule is made up of at least two atoms.

 

qualitative data: descriptions of events that do not use numbers If you report colors, smells, tastes, textures, or sounds, for example, you are making qualitative observations.

 

quantitative data: descriptions of events that do include numbers. If you count objects, or measure them with standard units, you are making quantitative observations. Quantitative observations are often made using tools.

 

surface tension: an effect that makes a liquid seem as though it has an elastic "skin." It is caused by cohesion between the surface molecules.