Key Idea: All atoms are extremely small.
Students are expected to know that:
- Individual atoms are much smaller than things that can be seen and even much smaller than very small things, such as dust, germs and other microorganisms, blood cells, and plant cells.
- This is true for all atoms.
- All atoms are so small that billions of them make up these small things.
Boundaries:
- The comparison with very small objects can be used to test students’ understanding of the relative size of atoms in relation to these objects. Students will not, however, be expected to know the actual size of atoms.
| Item ID Number |
Knowledge Being Assessed | Grades 6–8 |
Grades 9–12 |
Select This Item for My Item Bank |
|---|---|---|---|---|
65% |
78% |
|
||
An atom is smaller than the width of a hair, a cell in your body, and a germ. | 63% |
77% |
|
|
63% |
76% |
|
||
38% |
56% |
|
Misconception |
Student Misconception |
Grades |
Grades |
|---|---|---|---|
17% |
9% | ||
12% |
7% | ||
A grain of sand is smaller than an atom (AAAS Project 2061, n.d.). | 12% |
8% | |
9% |
8% | ||
The width of a hair is smaller than an atom (Tretter et al., 2006). | 8% |
6% |
Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.