Mystery Powder - Inquiry

materialsPurpose: To assess student levels of scientific inquiry, procedural science, cooperation, and communication. This lab is used as a pre-assessment for identifying which science practices (standards) need to be focused on within the unit of science and the scientific method.

Overview: Students are given an open-ended activity and asked to solve a problem. As a group, they determine the identity of a mystery substance, write a summary statement that uses evidence to support their claim (answer) and develop a procedural lab for middle school science students.

There is no hand-out for this lab and only minimal instructions, materials given to the student can vary.


1. Test-tubes, vials, or other containers filled with

1. Baking Soda
2. Corn Starch
3. Flour
4. Salt
5. Sugar (optional)
6. Slush powder or white gelatin (optional)
7. Sugar substitute (optional)

2. One unknown vial per group containing any of the above materials, vials marked with a number. Mixing materials is also acceptable and can make the task more challenging. Each group had a different unknown.

3. Beakers, cups, or dropper bottles filled with

1. Water
2. Iodine
3. Vinegar

4. Petri dishes, cups, tins, coffee filters, or other containers for mixing and testing ingredients
5. Stirring rods, popsicle sticks, or straws for mixing

6. pH paper (optional)
7. glucose test strips (optional)
7. Hand lenses (optional)


Advanced biology students usually are quick to plan and test the materials, some just using a visual assessment of the powders and comparing the appearance.

Students write a short analysis that identifies the powder and use evidence to support the claim. Some will use multiple statements of evidence (exemplary) and some may only use one piece of evidence (beginning.) See rubric.

Students then convert this inquiry lab to a procedural lab where they write the steps for testing the mystery powder so that the lab could be repeated with younger students. Steps are assessed on the clarity of the instructions and the separation of the variables being tested. (see rubric)

  Beginning Capable Accomplished
Working Together

Does not engage in activity or works against group goals

Actively works toward group goals, contributes knowledge, engaged Actively works toward group goals, contributes knowledge and opinions, listens to others, helps group implement necessary changes
Identification of unknown (oral) Unknown is not identified, group needs help refining their experiment to find the unknown Unknown is identified, group needs prompting to explain how they know what it is Unknown is identified, group can explain how they know with minimal prompts
Identification of unknown (written) Unknown is not identified, claim is not supported by evidence Unknown is identified, claim backed with at least one observation or test Unknown is identified, claim backed with 3-4 observations and tests
Procedural Lab Steps are unclear, unsafe, and unlikely lead to an identification Steps are somewhat unclear, could possibly lead to an identification Steps are clear, concise and will lead to an identification of the substance if the steps are followed correctly

Next Generation Science Standards

The eight practices of science and engineering that the Framework identifies as essential for all students
to learn and describes in detail are listed below:

1. Asking questions (for science) and defining problems (for engineering) ✓
2. Developing and using models
3. Planning and carrying out investigations ✓
4. Analyzing and interpreting data
5. Using mathematics and computational thinking
6. Constructing explanations (for science) and designing solutions (for engineering) ✓
7. Engaging in argument from evidence ✓
8. Obtaining, evaluating, and communicating information ✓

Common Core Standards

CCSS.ELA-LITERACY.RST.11-12.3 - Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text. ✓

CCSS.ELA-LITERACY.SL.11-12.1.B - Work with peers to promote civil, democratic discussions and decision-making, set clear goals and deadlines, and establish individual roles as needed. ✓

CCSS.ELA-LITERACY.WHST.11-12.1.A - Introduce precise, knowledgeable claim(s), establish the significance of the claim(s), distinguish the claim(s) from alternate or opposing claims, and create an organization that logically sequences the claim(s), counterclaims, reasons, and evidence. ✓

AP Biology Science Practices

3: The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course. ✓

4: The student can plan and implement data collection strategies in relation to a particular scientific question. (Note: Data can be collected from many different sources, e.g., investigations, scientific observations, the findings of others, historic reconstruction and/or archived data.) ✓