Lesson 19: Assessing Learning in Scien ce

I. Description

With regard to teaching the Earth concept, educators have the illusion that providing some proof of the spherical shape of Earth w ill convince the pupils about Earth's shape and, as a by-product, w ill change th e ir understanding of the "nature" of cosmic space. Such proofs, when given w ith out considering the pupils' preconceptions and w ith o u t confronting them explicitly, often do not serve this purpose.They do not have the intended effect of causing the pupils to modify th e ir belief about Earth's shape, and needless to say, they do not influence the pupils' notions of cosmic space. The notion of cosmic space requires direct and explicit didactic treatment. (Nussbaum 198 9:1 90)

Earth science involves the study of Earth's composition, its layers, and the activity w ith in the layers, oceans, and weather systems. The study of astronomy is often included. Much of what is known about the earth and the rest of the universe is based on inferences. Thus, as Nussbaum (1989) points out, much of earth science has to be ta u g h t through didactic methods. It is d ifficu lt to collect data through observations because change occurs on a grand scale and over very long periods of tim e. The form ations of most earth science concepts were developed by using sophisticated technology.Theories of plate tectonics, for example, were developed in part by collecting samples from hundreds of feet below the earth and the ocean in different parts of the world. Seismographic data collected over many years were also used to develop an explanation for the movement of earth plates. The same is true for astronomy. Thus, making papier-mache planets does not lead to understanding anything about them. This is merely an art exercise. Usually, the planets are not made to scale, and their surfaces are not reproduced accurately either.

These science concepts have been incorporated into curriculums with little consideration as to w h e th erthe children are developmentally ready to understand them.The plate tectonics theory was first introduced into the science curriculum at the high school level.The students collected actual data about earthquakes and volcanic activity.They studied maps of the continents and read about the composition

of land masses to understand how they have may f it together at one tim e. However, now the study of plate tectonics can be found in the early grades. The children cut out continent shapes and glue them together or make them out of clay and push them over each other to sim ulate what happens when continents collide. Thus, a theory developed through a complex process of collecting data and drawing inferences has been reduced to a dem onstration of showing objects moving over each other. This representation has no meaning to primary children, since the concepts are so far removed from th e ir own experiences and they are not d e ve lo p m e n ta l^ capable of understanding them . Remember, plate tectonics is a theory that is not based on direct observations. It is an explanation that most scientists accept based on the data they have.

The fo llow ing activities are basically sim ulations w ith observable data.

II. SAMPLE LESSON PLAN

Lesson 1: Scale Models of Planets

Goals

• To simulate the distances and diameters of the planets of the solar system

• To create scale models based on a ratio of the actual distances and diameters of the planets to one another

Grade Levels

• Upper grades

Materials

• String

• Construction paper

• Popsicle sticks

Instructions

Representing the distances and sizes of planets mathematically can be very helpful for the students in understanding the tremendous differences in measurements in outer space.

1. Have the students find out the actual distances, in kilometers, between the Sun and the planets of the solar system. Create ratios of kilometers to meters.

2. Cut lengths of string, in meters, that represent the distances between the planets and the sun.

3. Find out the actual diameters or circumferences of the planets. Use the metric scale to make circular cutouts of each planet, represented in centimeters.

4. Write the names of the planets on the circular cutouts. Glue them to popsicle sticks. Attach one end of the string to the planet cutout.

5. Take the children outside to a large area. One student represents the Sun and holds the unattached end of all the strings.

6. Other students hold the planet cutouts and walk away from the sun u n til the string lengths are fu lly extended. The planet holders slowly walk in a circle around

The students whose planets are closer to the Sun w ill complete the circle before the student holding the earth. The students w ith planets that are at a greater distance from the Sun w ill take longer to complete th e ir orbits. The students can count the num ber of Earth circles for each planet to know the num ber of years it takes for other planets to complete th e ir orbits around the Sun.

Lesson 2: Plaster of Paris Volcanoes

Goal

• To create a model of lava flow

Grade Levels

• Upper grades

Materials

• Plaster of Paris (Alternatives include chalk and water, lim e and water, soy powder and water, acrylic undercoat from the hardware store, matte m edium or gelatin).

• Crayons

• String

• Hot Plate

• Paper cups

• Metal co n tainerfo r b o iling water

• Safety goggles

Background Information

To stim ulate volcanic activity, crayons submerged in plaster of Paris are placed in boiling water. As the water boils, the heat penetrates the mold and melts the crayon. As the pressure builds, it forces the melted crayon to travel up the string to the outside. The water has to boil long enough for the crayon to m e lt inside the plaster of Paris. This stim ulates underground volcanic action as well as the movement of molten rock. Before doing this activity, the students can read about the various types of volcanoes and identify the types that are shown in the sim ulation.

The students must wear safety goggles as they make observations around the boiling water. Make sure the boiling water is not too close to the edge of a table and that no one trips over an electrical cord. The students can make observations in small groups.

instructions

1. Take a piece o f string, approxim ately 6 centimeters long, and rub it w ith a piece o f wax to coat it. Tie a piece of crayon to one end of the string.

2. Prepare a mixture of plaster of Paris or its alternative. Cover the bottom of a paper cup with the mixture.

3. Place the crayon in this mixture and add more plaster of Paris u n til the cup is between one-half to two-thirds fu ll. The end of the string should protrude from the plaster.

4. Let the cup set overnight so that the plaster of Paris dries. On the follow ing day, strip away the paper cup.

5. Place the plaster of Paris mold in water in a metal pan. The pan should be deep enough so that the water covers about two-thirds of the mold.

6. Place the pan on a hot plate and bring the water to a boil.

Suggestions

• Note where the molten crayon emerges from the plaster of Paris.

• Explain why it comes out from several different places.

• Compare what the books say about volcanic activity w ith what happens in this sim ulation.

III. Application

c ^ Answer the guide questions. 1. Cite some challenges that the teachers usually encounter in using sim ulations and models in class. 2. What other tools can the teachers use in order to make the class discussion on earth science topics more engaging for the students?

U N I T IV: ASSESSMENT STRATEGIES FOR SCIENCE

lesson 19: Assessing Learning in Science

Learning Objectives

At the end of this lesson, you should be able to:

• characterize effective assessment;

• discuss principles of assessing learning in science;

• explain the emphasis or focus of modern assessments in science;

• examine assessment strategies in terms of th e ir advantages and im p le m e n ta tio n g u id e lines; and

• explain ways on how to make assessment engaging and effective.

II. Learning Activities

Assessment is the ongoing process of gathering, analyzing, and interpreting evidence of student learning. Teachers reflect on fin d in g s in order to make informed and consistent ju d g m e n ts to improve student learning. Three types of assessment may be utilized by the teachers inside the classroom.

• Assessment for le arn ing: a form of formative assessment that occurs when assessments are integrated w ith instruction and help the teachers m onitor the students' progress, identify th e ir learning needs, and adjust th e ir instruction accordingly. The teachers provide im m ediate feedback so that the students become self-directed, metacognitive, and successful. • Assessment as learning: a form of formative assessment occurs when the students reflect on and m onitor their progress to inform their future learning goals. • Assessment o f learning: a form of summative assessment that occurs when the teachers use evidence of student learning to make ju dgm ents on the students' achievement against goals and standards.