During this lesson, students will work individually to identify a mystery powder. Students will have the opportunity to test known powders with different substances and record observations. Students will develop a plan that can be used to identify the mystery powder (which can be one powder or a mixture of 2 or 3 powders). Students will enjoy exploring the mystery powder to determine what it contains.

Baking soda, Plaster of Paris, cornstarch, salt, sugar, vinegar, iodine, water, litmus paper, heat plate, cups, spoons, plastic plates, aluminum foil boats, "Mystery Powder Investigation" handout (see attached, "Mystery Powder Planning Guide" handout (see attached), film cannisters, different numbered "Mystery Powder" containers, identification key of numbered "Mystery Powders", safety goggles

Computer with Internet access

Students should be aware of proper lab safety procedures and have had practice with using litmus paper and/or pH paper for classifying a substance as acid/base or neutral.
The teacher will prepare the "Mystery Powder" containers before the lab and make a key for later reference. Powders used in the initial testing will be used to make the "Mystery Powders." Teacher should place one, two or three powders in each container and mix well. Each container should be numbered. Different powders and combinations of powders should be placed in each container. All reagents and materials should be prepared before the lab.

1.)Students will review acid/base/neutral substances by completing the on-line science lab on the website below.
(http://sv.berkeley.edu/showcase/index.html)
This website has on-line science experiments that can be used by students. Click on the "Alien Juice Bar."

2.)Review the use of indicator strips for pH determination as well as pH range for classifying a substance as acid, base, or neutral.

3.)Review the class lab safety rules with students and distribute safey goggles and aprons.

4.)Distribute the "Mystery Powder Investigation" handout attached and review directions for the lesson with the class. Explain the distribution method of known powders and testing substances.

5.)Cups of known powders will be distributed to tables of four students. Cups of liquid testing substances will be placed on the tables along with pipettes for each liquid. Vials of indicator paper will be distributed.

6.)Use the heat plate to assist students in determining how heat affects the tested powders. Each student will place a small amount of each powder in the foil container so that the powders do not touch. Place the foil container onto the heat element while the student makes his/her observations and records.

7.)Allow students to test the other powders with each testing substance and record their observations. Small amounts of each powder will be placed on the plastic plates and not allowed to touch. Liquid testing substances will be added to each powder and observations will be recorded.

8.)The liquid substance created after the addition of water will be tested by the indicator strips to test pH value. Have students classify the substance as acid, base or neutral and record it on the lab write-up handout.

9.)Make sure students have recorded observations from all tested powders and substances recorded on the data sheet. Have each student complete a planning guide to assist in developing a plan for identification of the unknown powder(s).

10.)Let students implement their plans to discover the contents of their "Mystery Powder" containers.

11.)Using the results from the known powders, each student should identify what powder or powders are contained in the "Mystery Powder" container.

12.)Debriefing of the activity will occur as each student states his/her identification of the "Mystery Powder" and further states reasons for his/her decision.

13.)Assessment of completed lab write-ups as well as use of data to correctly identify the unknown powder(s) will be done by the teacher.

"Mystery Powder Investigation" lab write-up with attempted identification of "mystery powder" using acquired data will be assessed. The Planning Guide will be checked for completion.

This student could be given only a single powder in his/her "Mystery Powder" container. The teacher will assist as needed.