November 6, 2011

November 6th, 2011

November 6th, 2011

We have a short week this week, and the students have a 4 day weekend followed by a late start on Tuesday.  Everyone should be well-rested by next week!

Events of the Past Week

Monday - To begin class, we took the mass of our eggs and measured the volume of liquid in our cups after the weekend.  They were then placed in distilled water and left to sit overnight. 

We then went over our quiz from Friday.  After that was done, we began a lab looking at plant and animal cells.  We accomplished the task of looking at cheek cells during this class period.  The students should have been able to identify the cell membrane, cytoplasm, and nucleus in the cheek cell. 

Tuesday - The class periods were all shortened this day due to it being a late start.  The students were able to look at onion cells stained with iodine during the class period, and should have identified the cell wall, cytoplasm, nucleus, and nucleolus.  This was done after taking the mass of our eggs, measuring the volume of liquid left in our cups, and placing the eggs in 75 mL of corn syrup.

Wednesday - This was the 50th day of school, so no homework was allowed to be assigned, and no tests could be given on Thursday. We began class by taking the mass of our eggs, measuring the volume of liquid in our cups, and throwing everything away.  Since the lab questions could not be assigned to be due on Thursday, I let the students know that they would be due on Friday.

After we were done cleaning up our lab, I began to lecture about the structure of the cell membrane, as well as the concepts of diffusion, osmosis, facilitated diffusion, hypertonic, isotonic, and hypotonic solutions.  In the past, the concepts of hypertonic, hypotonic, and isotonic have been confusing for my students (as well as for the students of other teachers).  If you can encourage your children to study those terms it will help them on their upcoming quiz and test.

Thursday - I finished lecturing about the way materials move into and out of cells by introducing the concept of active transport.  When the students were done taking notes, we moved on to a worksheet that helped to review the concepts from the lecture.  Students were to finish that worksheet for homework, in addition to completing the egg lab questions.

Friday - Due to the shortened periods and amount of time needed in each class period to complete our egg lab, the quiz that was originally scheduled for today was pushed back until Monday.  Instead, we did two labs investigating osmosis and diffusion.  The first lab experiment involved putting a solution of egg white (protein), glucose (monosaccharide), and starch (polysaccharide), into a semipermeable bag, and then putting the bag in a beaker of distilled water.  The purpose of this lab was to investigate what effect the size of a molecule has on its movement through a membrane.  Through testing the solution in the beaker for the presence of monosaccharides, proteins, and polysaccharides, the students learned that small particles like monosaccharides can pass through a membrane, while larger particles, like proteins and polysaccharides, are too big to fit through a membrane.

While the students were letting their bags sit in the beaker of distilled water, they looked at two wet mounts I had set up at microscopes at my desk.  The students did not set up the slides themselves because 13 of the 15 microscopes in the classroom were in use for a lab practical that was set up for my seniors.  The freshmen observed purple onion cells that were soaked in deionized water on one slide, and purple onion cells that were soaked in salt water on the other slide.  Ask them to show you their drawings and explain what happened on each slide.  They should be able to use terms like:  plasmolysis, hyptonic, and hypertonic in describing what they observed.  For homework, the students were to complete the questions associated with the purple onion lab.  They will be given time on Monday to work on the questions associated with the semipermeable bag lab. 

Upcoming Events

Monday - Class will begin with a short, 10 question quiz on the topics that were covered in lecture and lab during the previous week.  Afterwards, students will be given time to work on finishing the questions from the semipermeable bag lab.  Finally, when they complete those questions, they will be given a review packet on the topic of cells.  Homework will be to finish the review packet.

Tuesday - We will begin by going over the questions in the review packet together.  Then the students will do the review activity with the butcher paper on each lab table that I described in the previous post.  Homework will be to study for a test on Wednesday.

Wednesday - The students will take a test of approximately 60 questions on cells.  The other accelerated biology teachers and I have a set of 48 questions that we will all be giving so that we can compare data on how our students are doing on several different topics within our unit.  Hopefully, this will lead to discussions of what each of us is doing that helps our students learn the material in this unit to find what approaches work best for students.  The other 10-12 questions will be specific to material done in our class.

Thursday - We will take a good amount of class time on Thursday to review the results of our cell test.  Students will analyze which topics they did well on, and which they could have performed better on, and do test corrections on those questions that they missed.  Finally, students will be given a brief reading assignment for homework over the weekend.


Graba Geek of the Week

My geek of the week actually goes back to our organelle presentations.  Alexandra Baumgart's presentation was one of the best presentations I have seen a freshman give in 14 years of teaching.  She took the risk of singing her part of the presentation solo in front of her peers.  This was very brave.  Alexandra did an outstanding job of singing her part, the information was factually accurate, and everyone was paying attention to her.  Great job, Alexandra!  I would not have been brave enough to do something like that when I was in high school!

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