Description:

Questions in the observation category assess pupils' ability to use a variety of senses to observe data in a certain way- a scientific way. All observing is selective and guided by a purpose. The general purpose in this test is that shared by scientists: discerning regularities, similarities and differences, patterns of various kinds and significant or systematic changes with time.

The assessment reflects a view of observation as the collection and interpretation of real data where little or no initial filtering out of detail has been made. For this reason observation is tested by a variety of practical tasks.

This task is designed to take students approximately 15 minutes to complete.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Motions and forces

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data

National Science Education Standards:

12 B PS 4: Motions and forces: Grades 9-12
4.1 Objects change their motion only when a net force is applied. Laws of motion are used to calculate precisely the effects of forces on the motion of objects. The magnitude of the change in motion can be calculated using the relationship F=ma, which is independent of the nature of the force. Whenever one object exerts force on another, a force equal in magnitude and opposite in direction is exerted on the first object.

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

General Instructions to the Teacher:

This task is designed to take students approximately 15 minutes to complete.

Students will be working individually during this exercise.

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

Materials for "Swinging":

• 2 clamp stands
• 1 metal bar
• 1 wooden rod with holes in either end
• 2 strings of untwisting cord
• 2 spheres or heavy beads (one yellow, one black)
• 1 card with starting line
• 1 stop clock
• 1 pencil
• chalk
• tape

Advance Preparation:

• Create swing stand with the two clamp stands and the metal bar between the two.
• Tie beads to equal lengths of cord.
• Thread cord through wooden rod.
• Tie cords to metal bar and stand set up such that beads rest at equal lengths.
• Position wooden rod half way from metal bar to beads.
• Mark string with black pen ¾ way from metal bar to beads.
• Mark a starting line on an index card and tape beneath apparatus so that beads will swing from starting line.

Safety:

• 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:

• Cord can be tied around wooden rod then untied and moved instead of having cords threaded through holes.