GEMS project

*112.6b (3) Scientific processes. The student uses critical thinking and scientific problem solving to make informed decisions. The student is expected to:

(A) analyze, review, and critique scientific explanations, including hypotheses and theories, as to their strengths and weaknesses using scientific evidence and information

*112.6b (4) Scientific processes. The student knows how to use a variety of tools and methods to conduct science inquiry. The student is expected to:

(A) collect and analyze information using tools including calculators, safety goggles, microscopes, cameras, sound recorders, computers, hand lenses, rulers, thermometers, meter sticks, timing devices, balances, and compasses

CONCEPT STATEMENT: There are millions of chemical substances in the world. Some are acids, some are bases, and the rest are neutrals. Each of these substances can be measured on a pH scale ranging from strong acids to neutral to strong bases. The scale range is from 0 (strong acid) to 14 (strong base). If you were able to mix a strong acid with a strong base the resulting substance would be a neutral. Students need to understand why certain substances are acids and bases. This leads to further investigation into the properties and concentrations of these substances.

PERFORMANCE OBJECTIVES: Students will be able to:

1. Determine that certain substances are acids and others are bases.

2. Understand that an acid added to a base will result in a neutral.

3. Determine the effect of different concentrations of acids and bases on the color of cabbage juice.

4. Understand that all kinds of chemical substances have different concentrations.

RESOURCES: For the class:

*Pink, green, and purple chalk

*Acid and base solutions from the previous lesson plan

*32 oz. cabbage juice

*1 roll of masking tape

*4 plastic cups

For the groups of 4-6 students:

*Previous acid and base solutions from previous lesson plan

*Leftover cabbage juice and acids, bases, and neutrals

*Medicine dropper

SAFETY CONSIDERATIONS: Students will be working with diluted acids and bases which can cause eye irritation. Hand washing will be required after each activity and safety goggles will be made available to each student. If any student experiences eye or skin irritation, they should inform the teacher immediately.

SUPLEMENTARY MATERIALS, HANDOUTS: More or Less Acid, More or Less Base, Acid + Base = Neutral

Engagement		Time: ____10____
What the Teacher Will Do	Probing Questions	Student Responses Potential Misconceptions
Make a low concentrated base solution and another highly concentrated base solution.	Why do you think one solution is darker than the other?	One solution has more acid/base in it. Misconception-That one solution has more cabbage juice to make it darker.

Exploration		Time: ___10_____
What the Teacher Will Do	Probing Questions	Student Responses Potential Misconceptions
Make a low concentrated acid solution and another highly concentrated acid solution.	Do you think the acid and base results correspond with each other?	Yes, because one is darker than the other just like the bases.

Explanation		Time: ____20____
What the Teacher Will Do	Probing Questions	Student Responses Potential Misconceptions
Draw a simple pH continuum for the students to see the levels of concentration.	Where do you think dark green is in relation to light green on the pH continuum?	Dark green Is the farthest to the right and light green is closer to the middle of the scale. Misconception-Some students might think that the darker colors go in the middle and fade out.

Elaboration		Time: ___15_____
What the Teacher Will Do	Probing Questions	Student Responses Potential Misconceptions
Have the students predict how much neutral solution would have to be added to make the acid or base a neutral.	How much cabbage juice will I have to add to make this acid/base solution a neutral solution?	This will just take some trial and error from the students. Some will over mix and some will under mix.

Evaluation		Time: ____5____
What the Teacher Will Do	Probing Questions	Student Responses Potential Misconceptions
Group Observations	How did your predictions compare to the actual results?	Some students will have the wrong predictions, but will be able to understand their misconceptions.
Turn in the observation worksheets used in the lesson