SCIENCE STRAND I
NATURE OF SCIENCE
Built into this science test is an assessment of students’ abilities and thinking habits in investigating science ideas. The nine outcomes in this strand overlap traditional science units and each other and should therefore be reinforced throughout the science curriculum—that is, should be taught in context—at every grade level.
1. Create and/or use categories to organize a set of objects, organisms, or phenomena.
This outcome tests students’ ability to group objects according to shared characteristics or attributes (structure, function, shape, state of matter, member of same food group, etc.); identify or create a classification system from observing objects that are already grouped or that can be grouped; and suggest objects that would belong to given groups or to groups created by the student. Test items will use illustrations of real-life objects or organisms that are familiar to fourth-grade students.
Students should be familiar with the process of sorting based on observable characteristics, and with explaining their reasons for creating categories. Memorized knowledge about specific classifications (such as mammals) is not nearly as important as a student’s ability to recognize or think through why something belongs (or doesn’t belong) in a certain group.
2. Select Instruments, make observations, and/or organize observations of an event, object, or organism.
Students should be able to select appropriate instruments (to make observations or perform a task); read or interpret data from graphs or tables; take measurements from representations of objects and/or instruments; and organize data, events, or observations into graphs, tables, or sequences. Test items will use illustrations of real-life instruments, objects, or organisms, and will show appropriate scales or units as needed.
Students should be able to use their natural senses, alone or in combination with representations of instruments or measuring devices, to describe or organize things factually—without opinion or inference. Because observations are often used to communicate information about events and objects to someone who has not observed that event or object, students should understand the importance of specific, factual descriptions or quantifications in observations. For instance, observations that an object “is black, about the size of a spinning (three-dimensional) penny, and can scratch a steel knife” communicate specific facts; the inference, “It’s a rock” does not.
In selecting or making readings from instruments, students should have the natural scientific habit of examining an instrument’s attributes: what it can do or measure, by what scale or units measurements are made, and so on. Similarly, in organizing observations or data, students should have the natural scientific habit of examining relationships between observations and sequence or time.
3. Identify and/or compare the mass, dimensions, and volume of familiar objects in standard and/or nonstandard units.
Students should be familiar enough with measurement concepts and basic SI units (Système International, or “metric” units) to do the following:
- recognize which SI units are appropriate for measuring mass, length, and volume;
- understand the decimal arrangement of SI units, some general relationships in scaling (a kilometer is larger than a meter, a centimeter is smaller than a meter, etc.), and some specific relationships between units (1 m — 100 cm; 1 km — 1000 m; etc.);
- make identifications or comparisons between measured objects as to lightest, heaviest, largest, smallest;
- use measurements given for two- and three-dimensional objects to determine a size relationship between those objects; for instance, if a sheet of material that is 1 cm wide and 1 cm high weighs 10 g, a sheet of the same material that is 2 cm wide and 2 cm high will weigh 40 g.
Students should have familiarity with measurement and with various standard or nonstandard units through having measured things themselves using a variety of measurement systems. Students should be able to use and interpret representations of objects and measurements, and in doing so should focus on the measurements given, not on a visual impression of size.
4. Use a simple key to distinguish between objects.
This outcome asks students to use a simple identification key (flow chart, dichotomous key, key in table or chart format) to distinguish between objects. This can mean using a key to identify which one of a set of objects can be identified by name or as belonging to a particular group; using a key or flow chart to separate large groups of objects into smaller groups; or analyzing a key to determine what characteristic always distinguishes one group or object from another. Dichotomous keys have two divisions or choices at each step and are typically based on an “either-or” classification system— either something has a particular characteristic or it doesn’t.
The use of a dichotomous key relies on the student’s ability to make clear observations and follow a logical sequence. Students should know how to proceed through a dichotomous key step-by-step, from the beginning, to identify a single unknown object or organism. Students should also be able to go to an object or organism identified in the key, and proceed “backward” thoroughly, step-bystep, to gather or identify all distinguishing characteristics of an object or organism. Important to such processes are practice in following written directions and in reading keys such as those found in many plant and animal “field guide” series.
Any illustrations in test items will clearly display all relevant key characteristics needed to distinguish groups or objects from one another.
5. Analyze a series of events and/or simple daily or seasonal cycles and predict the next likely occurrence in the sequence.
“Series of events” and “simple daily or seasonal cycles” include such things as phases of the moon; daily and seasonal orientation of the sun; daily cycles, seasonal cycles, or life cycles of plants and/or animals; or motion of gears. Students should be able to identify and/or explain simple patterns and relationships from graphs, charts, or drawings and predict the next likely occurrence in a pattern or sequence of events.
6. Evaluate a simple procedure to carry out an exploration.
This outcome requires students to identify which of several possible procedures should be used to explore or answer a particular question; identify which of several possible actions to take to gather information; evaluate whether a procedure or test will yield valid, “fair:’ or accurate results; and identify what information could be gained from an exploration. The outcome focuses on several aspects of scientific methodology—in particular, information gathering, performing experiments, interpreting the results, and drawing conclusions. Students should be able to identify a poor set-up or uncontrolled variables that could invalidate test results.
Students should be aware that there are generally several different ways to investigate something in science; they should also be used to thinking up possible methods of investigation, focusing on procedures that are logical and safe, and discussing their reasons for using or not using a particular method.
7. Identify and/or discuss the selection of resources and tools used for exploring scientific phenomena.
“Used for exploring scientific phenomena” is interpreted broadly to mean “used for a particular science process or with a particular desired result.” The focus is on identifying resources and tools that would be appropriate to use given the stated conditions. For instance, if a desired result is to build an outdoor storage container that would keep seeds from sprouting, the container would have to be waterproof.
Selecting instruments and tools relies on students’ abilities to make accurate observations and think logically about the task they are doing. Students should learn these principles through classroom activities that involve methods the students design or modify themselves.
8. Evaluate observations and measurements made by other persons.
Students should be able to evaluate the correctness or accuracy of simple observations or measurements; evaluate which, if any, conclusions can be drawn from data (that is, what conclusion, if any, is supported by the data); distinguish observations from inferences; and make and/or explain conclusions from data, measurements, or observations.
lnfrrences may be assumptions or reasonable conclusions drawn from observations, but they are not actual observations, and students should understand the difference. For instance, from a picture of five children running, observations could be made about the number of children and whether they were running in the same direction. Any statements about the reasons for the children running would be inferences.
Students should be used to comparing observations made by themselves and others to see if they make sense and are logical and accurate. People learn when they compare their learning to a new situation and figure out what any differences mean. Students should also be able to use observations and data in explaining their responses to short-answer and extended-response items.
9. Demonstrate an understanding of safe use of materials and/or devices in science activities.
This outcome focuses on identifying appropriate basic safety measures for certain situations or when dealing with certain materials and/or devices; identifying possible dangers to safety; and identifying which senses (sight, smell, hearing, taste, touch) are appropriate for certain situations. Safety measures and topics/issues addressed include the following: power tools and electricity; laboratory and general safety procedures and precautions; presence or need of adult supervision or consultation; and handling of unknown plants, animals, dry substances, or solutions. See Appendix C in Ohio’s Model Competency-Based Science Program for references to specific safety publications and guidelines.
Students should know the limits and rules of acceptable behavior in an activity; they should also be used to discussing safety as part of any activity, and should know they are to keep their teacher informed of things that go wrong in science activities.
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