CSCOPE 5th Grade Force Errors

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CSCOPE’s Incorrect Content on Forces

CSCOPE Force Lessons start in early elementary. Force is defined as a push or pull and this limited definition is used through 8th grade and probably through physics.

Correct
Force
is a push or pulling action on an object.

CSCOPE’s Incorrect Content on Forces

CSCOPE lists push and pull as types of forces along with gravity and magnetism. Push and pull or description of action.

Correct
A pushing force is an action on an object that moves the object away from you.
A pulling force is an action on an object that moves the object toward you.

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CSCOPE’s Incorrect Content on Forces

CSCOPE’s 5th grade assessment on forces for school year 2011-2012 contained the ramp diagram and question:

CSCOPE assessment has a cart on a fixed ramp. Question is not age appropriate, CSCOPE answer is incorrect.

Correct Answer

First of all, no matter where the cart is placed on the ramp, the effect of gravity pulling the ramp down the incline is the same.

Question #9 has two different too many variables.

1. How gravity affects the movement of the cart. 

Since the cart is on a stationary ramp, the force of gravity acting on the cart never changes. Thus, this objective cannot be achieved with the materials provided unless one accepts that the gravity is constant and pulls the cart down the ramp.

2. How height affects the speed of the cart. 

Omitting the effect of gravity as a variable, the height of the cart on the ramp can be investigated. If the cart is placed at the top of the ramp, it will reach the bottom of the ramp at its top speed compared to being place mid-way or at any other place on the ramp. This is not because of any change in force acting on the cart. Instead, the speed of the cart at the bottom of the ramp is due to the distance it travels.

CSCOPE Science Experts did not value my input, but did make changes in the question for the next school year. It is also incorrect.

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For 2012-2013 the CSCOPE force lesson continues to investigate the effects of forces on objects on horizontal surfaces. But, I assume to add “rigor” the assessment again has the cart on an incline plane. But it doesn’t matter what the answer is because any answer that has the cart with different masses is ok.

A CSCOPE assessment to determine how mass affects the motion of a cart down a ramp.
Correct Answer

This problem is appropriate for high school physics, but not for 5th grade science.

Kids get the problem correct no matter their answer.  Thus, CSCOPE plans for students to learn incorrect answers or to never know what the correct answer are.

If CSCOPE is interested, when gravity is the only force acting on an object, mass doesn’t affect its motion. The equation for force is:  F=m x a (gravity)

On the ramp, gravity pulls vertically on the cart. The force of gravity has two component forces, one in the direction down the ramp and the other perpendicular with the ramp. No matter what the mass of the cart is, the acceleration of gravity is the same, 9.8 m/s

The only thing that changes the motion of the cart down the ramp would be the angle of the cart. This is assuming no friction or any force acting on the cart except gravity.

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