Mystery Material

The learning goals for this mini-lab is for students to investigate an unknown material, make and record detailed observations, analyze information and be able to use data/evidence to support their answers.

This activity can build students understanding of properties and the differences between states of matter.

Vocabulary:

-Observation

-Molecule

-States of matter

-Properties

This mini lab investigation can be completed in a 45-50 minute class period (for extension activities or a more in depth investigation, consider "Oobleck-What Scientists Do" Lawrence Hall of Science GEMS). This investigation is typically aimed at 5-8th graders, but can easily be scaled up or down. In order for students to carry out this investigation, they should be familiar with observational and data collection skills. They should also have a basic understanding of the states of matter.

This investigation has students trying to determine what state of matter a mystery material is. Students are to ultimately answer the question "could this material be used as body armor?" Students will manipulate the material in order to make observations and gain information on its properties. Based on their guided investigation students will determine what state of matter the material is and be able to give evidence to support their answer. You may choose to show YouTube footage (d3o on the Discovery Channel AU, Liquid Armor, MythBusters Walking on "Water") as a wrap up to the investigation explaining why the material behaves as it does and real world applications.

Procedure:
In a large bowl have students mix 250 grams of the "mystery material" (corn starch) with 250 mL of warm water. Mix the material by hand until combined into a uniform substance. (you can also prep this up to 2 hours ahead of time and may add ~ 15 drops of food coloring).

Let students have 5 minutes of open inquiry with the mystery material. Refocus students to complete the task at hand. Have students work their way through the questions.

Questions

1. Describe at least 5 properties of the material that you have created in as much detail as possible.
2. Pick up a handful and squeeze it. Describe how the material reacted?
3. Push your index finger slowly through the material until you touch the bottom of the bowl. What do you observe?
4. Now, try to punch your index finger quickly through the material and touch the bottom of the bowl. What do you observe?
5. Explain your observations in terms of how you think the molecules are probably behaving.
6. What state of matter is the mystery material? Explain your answer using your observations and notes to provide supporting evidence.
7. Could this material be used as body armor? Explain your answer.
8. What other real world applications or products could this material be used for?

I have my students wear goggles during this investigation and have them follow standard safety procedures. When I have had my students conduct similar investigations I found it to be very helpful to let middle-schoolers have 5-10 minutes of open exploration with the mystery material in order for them to focus down on the investigation at hand. Have a variety of materials (plastic silverware, washers, bolts, funnels, stoppers, corks, etc.) on hand for them to use in manipulating the mystery material.

Formative assessment can be done by observation during the inquiry, student's mini presentation, class discussion of questions and by reading student's answers to the questions. I may follow up this activity several days later with a quick write to look for misconceptions or concepts that should be reinforced.

Grade 6

I B2, B3 and B4

Scientific inquiry

Grade 6

II A4

Structure of matter

Grade 8

IB1

Scientific inquiry

(High School IIA6, IIA7, IIA9 Molecular nature of matter, intermolecular forces)