MS-PS2-2

SCUSD NGSS Curriculum Guide
 * MS-PS2-2: Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object. ** [Clarification Statement: Emphasis is on balanced (Newton’s First Law) and unbalanced forces in a system, qualitative comparisons of forces, mass and changes in motion (Newton’s Second Law), frame of refe[[image:scusdngss/catapult.JPG]]rence, and specification of units.] [//Assessment Boundary: Assessment is limited to forces and changes in motion in one-dimension in an inertial reference frame and to change in one variable at a time. Assessment does not include the use of trigonometry.//]

Science Background for the Teacher:
Teacher needs to know Newton's 1st and 2nd law of motion.

Below are two questions students should investigate with a scientific experiment.

"How does changing the force at a constant mass affect the distance that a projectile travels"

"How does changing the mass with a constant force affect the distance that a projectile travels"

(essential questions should be more about acceleration rather than distance because the acceleration is what affects the distance)

Key Vocabulary:

 * Force || Net force || [key vocab term for this performance expectation] || [key vocab term for this performance expectation] ||
 * Newton ||  ||   ||   ||
 * Projectile ||  ||   ||   ||

Possible Assessments (formative and/or summative):
Students create a written constructed response that provides an explanation of their testable question using evidence collected from their experiment. (CLAIM, EVIDENCE, REASON)

Key Student Activity:
Students will create a catapult that can project an object with a certain amount of force. See picture above.

Use newton's spring scales to measure out the forces on the catapult.

Students can use pennies that have been taped together as the projectiles (Make sure you warn them not to pull the rubber bands back too far and toward students. (Max of 5 newtons)

Students will answer: "How does changing the force at a constant mass affect the distance that a projectile travels" Have them keep the force the same, pulling 2 pennies, 4 pennies and 6 pennies with the same amount of force. Keep a record of the distances. You may want to have them take an average of 3 trials for each set of pennies.

Students will answer: "How does changing the force at a constant mass affect the distance that a projectile travels" have them use the same amount of pennies with different amount of forces, 1N, 2N, 3N, etc. Keep a record of the distances and take an average of 3 trials.

Construct a data table and graph for each experiment

Key Teacher Demo/Activity:
Teacher has a demo of a certain catapult, projecting a certain mass across the room.

Things to Avoid/Correct:
Reinforce the dangers of this catapult since you are projecting pennies. Don't point at a student and don't use too much force.

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

YouTube: Mr. Parr's newton's laws of motion video