GENERAL INFORMATION: 9th grade, Biology, pH lab.Students will demonstrate their knowledge of acids and bases by measuring and recording the pH of different common household substances. They will identify which substances are acids and which are bases based on the pH.
- How did the teacher come to do this lesson?
This is a commonly available and widely-used lab. The materials are inexpensive, the procedure is simple, and it’s a great way for students to connect pH with acids and bases. Also, students get to reinforce measuring accurately, which they learned in the previous unit.
- How did he/she pick the topic?
It’s part of the California standards. It's a great hands-on way for students to learn the material.
- Where did the materials come from?
Litmus and pH paper comes from any teaching lab supply source. Carolina is a good one.
- In general, how does the teacher think the students will respond to the lesson?
They like it. They get to move around a lot and play with litmus paper, which is fun because it turns colors. Plus, they are measuring the pH of stuff they have at home, like dishwashing liquid, milk and vinegar.
- Identify some students in the class who will like this lesson and do well on it.
E., J., Q., and S. are the superstars of the class. They are in different groups to try and peer-teach the other students.
- Identify some students who might have difficulty, either cognitive or behavioral and describe the problems they are likely to have and how the teacher might adapt for them.
The ELL students will need some support to make sure they understand the lab procedure, questions, and learned about acids and bases. They are working in groups, and that helps a lot. Also, they each have the lab handout, which guides them through each step. I circulate constantly to answer questions as they go.
DURING (observation)Is there a written or unwritten plan for this lesson?
Lab handout for each student.
Presentation on acids and bases beforehand.
Students take Cornell notes during presentation.
Teacher goes over instructions for lab orally but very slowly and clearly with questions to check for understanding.
- What are the objectives (if this/these are unstated, you will have to figure them out)
- How does the teacher know that the objectives were met at the end of the lesson (formative or summative assessments)?
Students peer-grade each other.
One student per lab group is randomly selected for grade.
- How does the teacher know as the lesson is going on whether the students are getting it? (Formative i.e. checking for understanding)
Teacher asks students to repeat in unison essential instructions of lab procedure to ensure safety (e.g. pour liquids slowly so they don’t splash).
Teacher circulates as students do lab to check for understanding
- Does the teacher make any adaptations to address the needs of the children who have difficulty?
- The students
with low grades are spread out evenly in lab groups with students that have
higher grades to encourage peer-tutoring.
- Can you clearly follow the procedures the teacher is using and the understanding of the science concept and do they relate directly to the objectives?
- What other non-instructional strategies supported or distracted from the teaching of this lesson?
AFTER (interview teacher, and if possible, some students)
- How did the lesson go?
Students had trouble determining whether to write a color or pH in the different columns.
· Did the teacher correctly predict the performance of specific students?Yes. He knew the students would mistakenly write the number down, instead of the color.
- Did the adaptations (if there were any) work?
- How about the class as a whole – were the students engaged?
- Did they learn the skills and or content?
- How does the teacher know whether they got it or not?
- Were there any logistical problems?
If you taught this lesson, how would you change it?I would have small aliquots of each solution at each lab station so students wouldn’t be crowding over each other to get supplies. I would love to brainstorm student ideas beforehand of substances they want to test. Also, it would be great to incorporate the use of a pH meter so students could reinforce the idea of accuracy. I would also love to tie this into an environmental lab to test the effects of acid rain on plant growth. Another idea is to follow up this lab with an inquiry-based lab where students design their own experiment to compare the effectiveness of different antacids.