Description:

Students study chemical elements as substances with properties that distinguish them from other elements. Students are instructed to determine some properties of several elements they are given. They study each element's magnetic properties (how the element responds to a magnetic field) and density (amount of mass in a given volume). Students group the elements according to their relative magnetic properties and densities and explain the basis of their classification system.

This task is designed to take students approximately 40-50 minutes to completely.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Matter and its transformation

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data
• formulating conclusions from investigational data
• applying scientific principles to develop explanations and solve new problems

National Science Education Standards:

8 A SI 1:  Abilities of scientific inquiry:  Grades 5-8

1.4 Develop descriptions, explanations, predictions, and models using evidence. Students should base their explanation on what they observed, and as they develop cognitive skills, they should be able to differentiate explanation from description — providing causes for effects and establishing relationships based on evidence and logical argument. This standards requires a subject knowledge base so the students can effectively conduct investigations, because developing explanations establishes connections between the content of science and the contexts within which students develop new knowledge.

1.8 Use mathematics in all aspects of scientific inquiry. Mathematics is essential to asking and answering questions about the natural world. Mathematics can be used to ask questions; to gather, organize, and present data; and to structure convincing explanations.

8 B PS 1:  Properties and changes in properties in matter:  Grades 5-8
1.1 A substance has characteristic properties, such as density, a boiling point, and solubility, all of which are independent of the amount of the sample. A mixture of substances often can be separated into the original substances using one or more of the characteristic properties.

4 B PS 3: Light, heat, electricity, and magnetism: Grades K-4
.3.4 Magnets attract and repel each other and certain kinds of other materials.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

National Council of Teachers of Mathematics:

Algebra (AL1): Understand patterns, relations and functions.

Algebra (AL3): Use mathematical models to represent and understand quantitative relationships.

Measurement (MEAS1): Understand measurable attributes of objects and the units, systems, and processes of measurement.

Number and Operations (NO2): Understand meanings of operations and how they relate to one another.

Data Analysis and Probability (DAP3): Develop and evaluate inferences and predictions that are based on data.

Communication (COM4): Use the language of mathematics to express mathematical ideas precisely.

Connections (CNX1): Recognize and use connections among mathematical ideas.

Representation (REP1): Create and use represenations to organize, record, and communicate mathematical ideas.

General Teacher Instructions:

This task is designed to take students approximately 40-50 minutes to complete.

Students will be working in groups of 4-6 for the experiment/activity part of this exercise. Each student must record the information in his or her own booklet (test papers). Allow from 20 minutes to complete the group work. If students are still working together 20 minutes after the testing begins, instruct them to cease their group work and begin individual work. At this point, they may no longer talk. Whether or not they are just beginning their individual work, remind students that they now have about 25 minutes to complete the individual activity.

Students should be ready to work as soon as the period begins. Group assignments should be made in advance. The materials should be set out at each lab station, if possible. A central supply area, if needed, should be easily accessible. All supplies should be clearly labeled.

Materials for "Classifying Materials":

At this station students should have:

• Aluminum rod
• Iron rod
• Lead rod
• Copper rod
• Nickel rod
• 10 ml graduated cylinder
• alnicomagnet
• safety gloves
• triple beam balance
• water
• paper towels
• 50 ml beaker or cup

Advance Preparation:

Group assignments, if used, should be made in advance.

Special Teacher Instructions:

Students should wear aprons and safety glasses while they are performing any of these experiments.

Students should test the magnetic property of each element by placing the element at one end of the magnet and observing the attraction, if any. Elements that are attracted to the magnet will be pulled toward it and stick to it. Materials that are attracted to magnets and that are themselves magnetic are ferromagnetic. Materials that are attracted to magnets but that are not themselves magnets are paramagnetic. In other words, two ferromagnetic materials will attract each other, but two paramagnetic materials will not.

The attraction between a given magnet and a paramagnetic material is likely to be a lot weaker than the attraction between the same magnet and a ferromagnetic material.

Expected results using the specified materials:

The density of a material is calculated by dividing the mass in grams by the volume in cubic centimeters.

• Be careful.
• Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.