Kara built a model of how molecules behave when they are in solid form. She filled a clear plastic box with marbles to the very top and put the lid on the box. When she shakes the box, the marbles can barely move.

Question

Which of the following is a limitation of Kara's model?
A.
The marbles must be held in a box, but solids hold together without a container.
B.
The marbles are all the same shape, but molecules all have unique shapes.
C.
The marbles are made out of atoms, but molecules are not.
D.
The marbles have limited motion, but molecules in solids move a lot.

Answer 1

The correct answer is:

A. The marbles must be held in a box, but solids hold together without a container.

This choice highlights the limitation of Kara's model since it suggests that her model does not accurately represent how solids are structured; solids maintain their structure without the need for an external container.