Today marked the first day of dissections (thanks to our DonorsChoose grant award!), with students working in teams of three to dissect a cow eye and a pig heart. Student feedback was overwhelmingly positive. Students who were apprehensive at first quickly engaged with the hands-on lab. Many were surprised at how different the organs were compared with the stylized pictures they had seen in textbooks. I was very impressed with how respectfully students treated the organs. The dissections were performed with care and clear attention to detail. Many students were able to trace the flow of blood through the heart. Students who dissected the eye noted the beautiful blue coloration of the cow eye retina, and may students were surprised by the onion-like structure and marble-like consistency of the lens. The hardness of opacity of the lens are due to the dissection materials being stored in a chemical fixative. Exploratorium has a guide available for the dissection of fresh cow eyes for students feeling inspired to connect with their local butcher.
Students dissected frogs and sheep brains today:
For the final 20 minutes of class, we reviewed critical course content in preparation for the Unit 2 Exam scheduled for tomorrow. White board notes are shown below:
Chapter 8 concluded with the Lesson 46 PowerPoint and Lesson 46 Worksheet. Lesson 46 brought together the various concepts needed to understand how molecules with certain properties can be detected by our noses, with our brain recognizing those molecules as having a specific smell. The ChemCatalyst asks students to model why perfume molecules can be smelled from across a room, but paper cannot (both placed near a sunny window). We sketched out a drawing of the scenario and modeled the response on the white board (pictured below):
We continued our study of polarity, this time exploring how the polarity of molecules might impact our ability to smell the molecule. Through the Lesson 45 PowerPoint, students learned that polar molecules are more likely to be detected by the nose as something with a scent although there are still polar molecules (like water) that do not smell. Students worked in pairs to cut out the molecules in the molecules handout and used the molecules to complete the Lesson 45 Worksheet. Students who would like to explore the polarity of molecules further are encouraged to visit the University of Colorado’s PhET molecule polarity simulation (or just click below).
For our entry task today, students assembled into their dissection groups, quickly assigned each other a number (1, 2, or 3) and then were assigned every third question on the worksheet (page 1 only). The entry task video is below and helps connect the work we have completed this far in Unit 1 (cells and organelles) and Unit 2 (body systems), with a preview of what is to come.
Dissections have arrived! We will begin by review the contents of the dissection kit each team will use, and we will review the safety precautions for conducting the lab. Next, students will assemble into three-person teams and determine who will take the lead for dissection the cow eye, pig heart, and frog. In addition, two teams will also receive a sheep brain. As preparation for the dissections, students will use the Chromebooks to watch their assigned how-to video (below) and carefully take notes:
Cow Eye Dissection:
Pig Heart Dissection:
Sheep Brain Dissection:
Mr. Joe Weiss from the PSSC Marine Tech Lab visited with students today to share information about the Marine Science & Technology program he offers at the Marine Tech Lab down at Seahurst Park. Mr. Weiss explained the program (his PowerPoint presentation provides an excellent overview), answered student questions, and provided materials about PSSC for interested students to review and discuss with their counselors here at HHS. Students are also encouraged to visit the PSSC website to learn more about all of the different programs offered.
After, we reviewed the concepts likely to be included on the Unit 2 Exam scheduled for Thursday next week. Students may prepare one page of notes (notebook paper, front and back) to use on the exam. Specifically, students should review:
- the 4 classes of biomolecules (including the subunits and atoms comprising the subunits)
- negative feedback
- potential and kinetic energy
- the connection between matter and energy
- conservation of energy and matter
- inputs and outputs of cellular respiration, photosynthesis, and combustion
- how to write a scientific explanation using a claim, evidence (data), and scientific reasoning
After learning about the concepts of electronegativity and polarity in yesterday’s lesson, students learned how scientist Linus Pauling assigned electronegativity values to individual atoms as a measure of how strongly an atom attracts electrons. The Lesson 44 PowerPoint includes a copy of the periodic table with electronegativity values for each element. It also explains the difference in electronegativity between covalent bonds (0.5 and less), polar covalent bonds (between 0.5-2.1), and ionic bonds (greater than 2.1). The Lesson 44 Worksheet provides students with the opportunity to calculate the electronegativity difference between two atoms in a molecule and to use that information to determine the type of bond that is present between the two atoms. For homework, students are assigned questions 1-9 (odds).
Today marked the beginning of the Nervous System Project. Students with a grade of a C or higher have earned the opportunity to extra credit in exchange for researching an aspect of the nervous system of interest to them. As a student-driven project, the purpose is to provide students with the time and space to research topics like depression, Alzheimer’s Disease, Parkinson’s Disease, or any other condition of interest to the student. The goal is to learn more about the condition and to explore the condition at the system, organ, cell, and molecular level. Students were encouraged to explore the role of neurotransmitters in their chosen condition. To help support students, one possible research path might be:
- Select a condition that affects the nervous system
- Select a neurotransmitter known to be involved in the condition
- Research the function of the neurotransmitter and its’ receptor
- Research the source of the neurotransmitter (which cells release it?)
- Research the neurotransmitter receptor – what is it, and where is it expressed?
- Research how the neurotransmitter imbalance may occur
- Research available treatment options
Summarize findings in a Google Slides document (then share it with Mr. Swart)
+30 EC for completed project; +5 EC for presentation to class (optional)
We began class with a Crash Course chemistry video about polar and non-polar molecules:
We then worked through the Lesson 43 PowerPoint and followed that with the Lesson 43 Worksheet and accompanying cartoon. One of the vocabulary terms, dipole, is introduced in the Crash Course video along with the concept of dipole moment. For more on dipole moment, check out the Khan Academy video below:
Dipole moment: Predicting the molecular dipole moment based on the molecular geometry.
For homework, students are assigned questions 2, 4, and 6.
Chapter 8 began with a lab designed to introduce students to the concept of polarity. Students filled burets with water, vinegar, and vegetable oil and observed the path of the liquids in the absence or presence of an electrically charged wand. The wand consisted of a long balloon rubbed vigorously on students’ hair to generate a static charge (build-up of electrons) on the balloon. Students then observed how the negatively-charged balloon “pulled” the stream of water toward the balloon (pictured below along with the lab set-up). Students worked through the Lesson 43 Worksheet while completing the lab. After the lab, we reviewed the key vocabulary and concepts presented in the Lesson 43 PowerPoint. For homework, students are assigned questions 4-6.
We began class with a reminder that the semester ends next Thursday, January 28. Students were informed that if they have a current grade of a C or better, they will be able to participate in an extra credit opportunity (the nervous system project) to be explained tomorrow. Student projects will determine which groups are able to dissect sheep brains next week. Students with a D or below will work in small groups with me this week to help them catch up. Students who still have a D or below as of Tuesday next week will continue to catch up on required classwork and will not participate in the dissection lab. There will be a Unit 2 Final Exam on Thursday (1/28).
Students then had the next 20 minutes to complete the take-home quiz from Friday (only about 1/4 of students in all of my classes used the three-day weekend to complete the quiz). After the quiz, we reviewed two of the more challenging questions, connecting the path that explains why excess fertilizer used by farmers near the Mississippi River ends up contributing to the dead zone in the Gulf of Mexico. Links to pictures shown in class, as well as pictures of the white board notes are provided below.
Map of the Gulf of Mexico showing bordering states
Image of the dead zone (red = very little oxygen, blue = normal oxygen) in the Gulf of Mexico
Map of the United States highlighting the location of the Mississippi River (in red)
White Board Class Notes: