Description:

The task assesses students' abilities to develop a hypothesis, design an experiment, utilize experimental data, and apply their understanding to an additional situation.

This task is designed to take students approximately 45-60 minutes to complete.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Friction, Experimental Design

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 necessary to do scientific inquiry: Grades 5-8
1.2 Design and conduct a scientific investigation. Students should develop general abilities, such as systematic observation, making accurate measurements, and identifying and controlling variables. They should also develop the ability to clarify their ideas that are influencing and guiding the inquiry, and to understand how those ideas compare with current scientific knowledge. Students can learn to formulate questions, design investigations, execute investigations, interpret data, use evidence to generate explanations, propose alternative explanations, and critique explanations and procedures.

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.

(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:

AL1: Understand patterns, relations and functions:
Grades 6-8 f. represent, analyze, and generalize a variety of patterns with tables, graphs, words, and, when possible, symbolic rules

AL4: Analyze change in various contexts:
Grades 6-8 e. use graphs to analyze the nature of changes in quantities in linear relationships

DAP3: Develop and evaluate inferences and predictions that are based on data:
Grades 6-8 c. use observations about differences between two or more samples to make conjectures about the populations from which the samples were taken

PS2: Solve problems that arise in mathematics and in other contexts:
Grades 6-8

General Instructions to the Teacher:

This task is designed to take students approximately 45-60 minutes to complete.

Students will be working individually during this exercise.

Students should be ready to work as soon as the period begins. 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 Friction:

• boards (about a foot long but all boards the same length)
• eye hooks
• wood blocks- small and large of consistent size
• metal washers
• string
• hooks
• sandpaper
• felt
• scissors
• glue
• marking pen
• ruler

At this station students should have:

• 2 wooden blocks with hooks
• string with a hook
• 1 plain wood board with eye hook
• 1 felt covered board with eye hook
• 1 sandpaper covered board with eye hook
• 35 metal washers

Advance Preparation:

For each student prepare the following:
• Size three boards to 12 inches (can be 1x4 or 2x4)
• Screw eye hooks into one end of each board
• Cut out sandpaper and felt to fit one side of the board (12x4)
• Glue sandpaper and felt, each to one of the boards
• Draw a line 4 inches from the side without the hook
• Tie the string to a hook
• Prepare a small block and a large block (blocks used here were 2x4x4 and 2x2x4)
• On each block label a side that is 2x4 "B"
• Screw hooks into the end above each "B"

Safety:

• Caution the students about the sharpness of hooks and weight of the boards if applicable.
• 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.

Extensions/modifications:

• This test has two sections and four parts which could be spread out over a number of days if desired.