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Assessment in the Science Classroom by Vilimaka Foliaki

What is assessment? In the classroom, assessment can be defined as a systematic process of gathering information about what a student knows and is able to do. Why assess? The most important purpose of classroom assessment is (not to evaluate or classify student performance, but) to inform teaching and improve learning, and to monitor student progress in achieving a set of desired learning objectives/outcomes. Types of assessment Assessment can be formative, summative, or diagnostic. i.

Formative assessment is given during the instructional unit or course and provides students (and teachers) with information about their progress in accomplishing the course’s learning outcomes. Formative assessment also evaluates the effectiveness of instructional strategies and content, sequence, and pace.

ii.

Summative assessment (evaluation) is based on an interpretation of the assessment information collected and is given at the end of a course/term/semester. It helps determine the extent of each student’s achievement of learning outcomes. It is used mainly to report students’ progress to parents, and other stakeholders.

iii.

Diagnostic assessment is given before instruction and determines students’ levels of understanding of concepts or topics before teaching actually begins.

Equity in Assessment Classroom assessment must be ‘fair’ to everyone. Equitable assessment is concerned with making assessment work for everyone. The quote on the left points out one very important issue to consider in classroom assessment In our classrooms there is always a wide diversity of students – even when students come from the same ethnic background, family, country, etc. If assessment is to serve all students equally well, we must have some insight into how we can best address some of the ingredients of this diversity. Students differ in the following ways:

Vilimaka Foliaki, ED350Science 2010

Culture, ethnicity, race and upbringing

Language proficiency

Gender 1


Learning style

Economic background

Other aspects of students’ lives and identities

Collecting information about what students know and can do It is important for us to be aware that most of the things that a teacher does in the classroom (e.g. asking questions, brainstorming, etc) are actually assessment. In other words, it is important for us to know that there are many ways, other than tests/exams, for collecting information about what students know and can do. The most common way of assessing science learning in the Pacific Island is the exam (which includes multiple-choice, short-answer-type, true/false tests). However, when science instruction becomes more student-centred and constructivist in nature, there is a need for science teachers to use a wider range of assessments. In a student-centred science classroom, the students are encouraged (and guided) to work independently of the teacher, and to work on a variety of tasks in which they are expected to physically demonstrate learned skills and knowledge. In addition, in such classrooms, prior knowledge is seen as the foundation of meaningful learning, and is assessed (or diagnosed) at the beginning of instruction. Assessing Prior Knowledge As mentioned in the above paragraph, prior knowledge is very important in learning. Constructivist science teachers believe that the neglect of prior knowledge can result in the students learning the wrong ideas (or not learn at all!), no matter how well new ideas are explained in the textbook, or lecture. In this workshop, we’ll continue to learn more about how to assess your students prior understanding of some science concepts. It is expected that you’ll be able to use your experience in this workshop to develop your own assessment probes for your own classroom.

Vilimaka Foliaki, ED350Science 2010

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SCIENCE ASSESSMENT PROBES Probe 1: What’s in the Bubbles? [Adapted from Keely, P., Eberle, F., and Tugel, J. (2007). Uncovering Student Ideas in Science, Volume 2:25.]

Ranita is boiling water in a glass tea kettle. She notices bubbles forming on the bottom of the kettle that rise to the top and wonders what’s in the bubbles. She asks her family what they think, and this is what they say: Dad:

“They are bubbles of heat.”

Sailesh: “The bubbles a re filled with air.” Grandma: “The bubbles are invisible form of water.” Shalini: “The bubbles contain oxygen and hydrogen that separated from the water.” Which person do you agree with and why? Explain your thinking.

Explanation The bubbles are water vapour- invisible form of water (gas state). Water vapour is not like steam, which contains some condensed liquid water. When water is heated, the energy supplied to the system causes an increase in molecular motion. If enough heat is supplied, the molecules have so much energy that they no longer remain loosely connected, sliding past one another as they do in a liquid. The energy now allows the attractive forces between the water molecules to be overcome, and they form an invisible gas (water vapour). Since the molecules in the gas phase are so much far apart than in the liquid phase, they have a much lower density, are more buoyant – causing them to bubble up and escape into the air.

Vilimaka Foliaki, ED350Science 2010

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Probe 2: What are clouds? On his way home with his mom and dad, little Jone watched the clouds moving in the sky. Wondering what clou ds were, he asked his parents. This is what his parents said: Mom: “Clouds are like balls of smoke from the fire.” Dad: “Clouds are balls of water in the sky”. After a while, Jone queried: “But we don’t get wet when we run through smoke! And if they were balls of water, why don’t fall down?” Which person do you agree with and why? Explain your thinking.

Explanation Clouds are masses of very fine water droplets – they are not bodies of water vapour! Water vapour is a colourless gas, and therefore it is invisible. Clouds are formed when the pressure is low (cloud formation is associated with low pressure systems). Atmospheric pressure at sea level is about 760mmHg (or 1 atmosphere) and it decreases with altitude.

Vilimaka Foliaki, ED350Science 2010

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Probe 3: Boil Water with Cold Water 1. Fill a conical flask ¾ full with water, put a few boiling chips in it, and heat over the burner and stand until boiling. 2. Ask the students the following questions: a. “What is the boiling point of water?” b. “How do you know that water is boiling?” c. “Can water boil at other temperatures?” The purpose of these questions is to elicit your students’ prior understanding of important concepts such as boiling, pressure, density, change of state, water vapour, etc. You could list down their ideas. 3. Attach a clamp on the flask's neck, shut the flame off and immediately close the flask with a one-hole stopper that is fitted with a thermometer. Have a students read off the temperature (should be about 98-100ºC). 4. Once the temperature has dropped to 90ºC (or even lower), invert the flask and hold it under a cold stream of water from the tap above a sink. Alternatively, wipe the bottom of the flask with a towel soaked in cold water. 5. Observe boiling water and have students read off the temperature. Write down your answers to the following questions: 1. Why does the water stop boiling after the heat is taken away? 2. At what temperature does water boil at normal pressure? 3. What is the cold water doing to the water vapour in the flask? 4. What do you think the pressure above the water in the cooled flask is? 5. What is the lowest temperature at which the water is still able to boil in the cooled flask? Explanation: Boiling point is the temperature at which the liquid and gas phases of a substance can exist in equilibrium (i.e. rate of condensation = rate of evaporation). Boiling point is affected by factors such as temperature, pressure, presence of solutes, etc. Do you remember LeChatelier’s Principle? This principle simply states that a system that is in equilibrium will always try to remain at equilibrium. By boiling the water, steam is formed and this replaces almost all the air above the water in the flask. By closing it off immediately after boiling point is reached with the stopper and the thermometer, the air is trapped out of the flask. When the flask is cooled off with the cold water, the water vapour above the water condenses on the colder surface and a partial vacuum (hence low pressure) above the water is created. This makes the water boil at much lower temperatures than the ‘normal’ boiling point of 100ºC.

Vilimaka Foliaki, ED350Science 2010

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Probe 4: TRAM it! Using the s,p,d,f-notation, write the electron configuration of the following elements: 1. C (Z = 6)

2. F (Z = 9)

3. K (Z = 19)

4. Zn (Z = 30)

5. Sc (Z = 21)

Vilimaka Foliaki, ED350Science 2010

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Assessment in the science classroom