3-PS2-1

SCUSD NGSS Curriculum Guide
 * 3-PS2-1: Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object. ** [Clarification Statement: Examples could include an unbalanced force on one side of a ball can make it #|start moving; and, balanced forces pushing on a box from both sides will not produce any motion at all.] [//Assessment Boundary: Assessment is limited to one variable at a time: number, size, or direction of forces. Assessment does not include quantitative force size, only qualitative and relative. Assessment is limited to gravity being addressed as a force that pulls objects down.//]

Science Background for the Teacher:
Each force acts on one particular object and has both a strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object. Forces that do not sum to zero can cause changes in the object's speed or direction of motion. The patterns of an object's motion in various situations can be observed and measured; when past motion exhibits a regular pattern, #|future motion can be predicted from it.

Key Vocabulary:
motion tension force slope push pull friction incline gravity balance

Possible Assessments (formative and/or summative):
Draw 3 things. Show where the forces are pushing on them.

Key Student Activity:

 * Helium balloon with weights. (helium pulls up, weights pull down) Make the balloon float in the air, not away
 * Shoe box with magnets. (see diagram) Turn box upside down to see if the force of the magnet can keep the paperclip suspended. (adjust length of the string). Also, add paperclips to see how many paperclips can be added, before the force of gravity takes over the pull of the magnet. Draw and label all the forces. (tension on the string, etc.) Teacher should supply list of terms for students to choose from.

Key Teacher Demo/Activity:

 * String holding a ball. (Hand pulling it up, gravity pulling it down)

Common Student Misconceptions:
An object sitting on a table, there is no force

Things to Avoid/Correct:
Terms vector quantity, magnitude, momentum. But the concept that some quantities need both size and direction to be described is developed.

====Other Resources (text, video, simulations, activities, models, etc..): ====