MEGA
Energy Changes
A decrease in energy in one object or set of objects always is accompanied by an increase in energy in another o…
Item EC067002: A battery in a handheld fan transfers energy to the fan resulting in the fan increasing in energy and the battery decreasing in energy.
An energy transfer model shows the direction of energy transfer between two systems. Each box in the model represents a system and the thick arrow between the boxes represents the direction of energy transfer. In parentheses under each box, is a description of how the amount of energy in the system changes.
A person puts two batteries into a handheld fan. Then she turns on the fan and the blades of the fan start to spin.
Which of the following models illustrates how the amounts of energy in the battery system and the fan system change when the fan blades start to spin?
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 365 |
6–8 n = 0 |
9–12 n = 324 |
Male n = 195 |
Female n = 125 |
English n = 303 |
Other n = 19 |
||
| A. |
 |
23% | NAN% | 24% | 27% | 17% | 23% | 21% |
| B. |
 |
38% | NAN% | 37% | 35% | 40% | 38% | 58% |
| C. |
 |
19% | NAN% | 17% | 19% | 18% | 18% | 5% |
| D. |
 |
21% | NAN% | 22% | 19% | 26% | 21% | 16% |
Post-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 436 |
6–8 n = 0 |
9–12 n = 397 |
Male n = 228 |
Female n = 159 |
English n = 368 |
Other n = 22 |
||
| A. |
|
10% | NAN% | 9% | 14% | 4% | 10% | 5% |
| B. |
|
64% | NAN% | 66% | 63% | 70% | 65% | 68% |
| C. |
|
12% | NAN% | 12% | 13% | 10% | 12% | 5% |
| D. |
|
13% | NAN% | 13% | 11% | 15% | 13% | 23% |