Science Assessment ~ Items ~ AP055005

A teacher shows her class a demonstration of a fan that spins over a lit candle. The students notice that the fan only spins while the candle is burning.

Watch the video to see the demonstration.

The students want to figure out whether the light from the candle, the air rising from the candle, or both of them are causing the fan to spin. They also want to know if energy plays a role. They conduct a series of investigations by placing a fan over different objects. The table below summarizes their findings.

Investigation #	Description	Was light observed?	Did air rise toward the fan?	Did the fan start to spin?
1	The fan is placed over a burning candle.	Yes	Yes	Yes
2	The fan is placed over a hot plate that is turned on a low setting.	No	Yes	Yes
3	The fan is placed over an LED light bulb that is turned on.	Yes	No	No

1. Based on the observations in the table, which of the following explains what caused the fan to spin?

A. The fan spins because of the light.

B. The fan spins because air is moving toward the fan.

C. Both the light and the moving air cause the fan to spin.

D. Neither the light nor the moving air causes the fan to spin.

2. What patterns in the data helped you decided whether light caused the fan to spin?

3. What patterns in the data helped you decided whether moving air caused the fan to spin?

4. One way to relate light, heat, and motion is through energy. Use ideas about light, heat, motion, and energy to explain why the fan moves during Investigations 1 and 2. Be sure to include evidence from the investigations in your explanation.

Details
Performance
NGSS

Topic: 3D Energy Tasks
Scoring Rubric: Q1; Student selects answer choice B

B. The fan spins because air is moving toward the fan.; Q2; Student described relevant patterns

In investigation 2, there was no light, but the fan started to spin.

In investigation 3, there was light, and the fan did not spin.

Note: Must reference more than one investigation [either explicitly or implicitly (e.g., using “only”)]. They should not receive credit for just writing that the air moved or that “Light did not cause the fan to spin.” They can reference an investigation by describing it (e.g., when there is an LED the fan does not spin).; Q3; Student described relevant patterns

In investigations 1 and 2, air moved up toward the fan, and the fan started to spin.

In investigation 3, no air moved up toward the fan, and the fan did not spin.

Note: Must reference more than one investigation [either explicitly or implicitly (e.g., using "only)]. They should not receive credit for just writing that the air moved or that "The air that comes from the lit candle is moved toward the fan and it causes the fan to spin."

Note: No credit is received for only mentioning heat.; Q4; 1. Student makes a claim that answers the question

The fan spins in investigations 1 and 2 because

the rising air pushes/hits/exerts a force on the fan.

the air transferred energy to the fan.

the fan gets energy from the air.

convection currents in the air.

2. Student lists evidence

The fan only spins when the air is moving upward or the fan only spins in investigations 1 and 2.

3. Student either states or uses a general science idea

When two objects collide, energy is transferred from one to another resulting in a change in motion. (i.e., the moving air exerted a force on (hit or collided with) the fan that transferred energy to the fan causing it to start spinning). [links force and energy transfer]

Note: It may be useful to keep track of students who use the term "force" vs. "hit" or "collide." It's not a requirement but it is what differentiates the middle school DCI and elementary school DCI.

4. Student uses reasoning to link evidence and science ideas to the claim

There is air rising toward the fan. This air exerts a force on the fan in investigations 1 and 2 which transfers energy and causes the fan to start spinning.

Percent of Points Earned

Chart showing distrubtion of responses for Item AP055005

Points Earned

	Avg. Earned	Possible	Percent
Q1	0.61	1	61%
Q2	0.49	2	25%
Q3	0.59	2	30%
Q4	0.27	4	7%

Overall Task Difficulty

	Total Points Earned	Total Points Possible	Total Percent
	1.96	9	22%

n = 281

Note: The total percent is a weighted average based on the total number of points earned divided by the total number of points possible.

Science and Engineering Practices: SEP4 Analyze and interpret data to provide evidence for phenomena.
SEP6 Apply scientific ideas, principles, and/or evidence to construct, revise and/or use an explanation for realworld phenomena, examples, or events.
Crosscutting Concepts: CC1 Patterns can be used to identify cause and effect relationships.
Disciplinary Core Ideas: PS3.C When two objects interact, each one exerts a force on the other that can cause energy to be transferred to or from the object.

Science Assessment

Item AP055005: Analyze and interpret data from investigations to identify patterns and use energy transfer ideas to explain the cause for the phenomenon of a fan spinning over a lit candle. (CR version)