Apologia Biology: Cells and Experimental Design

Experimental design is key for me.  It’s more than the scientific method.  This coming week we are only meeting on Tuesday—Thursday is a holy day.  Several of the kids serve at Mass, so we decided to cancel classes.  I have gallons of hydrogen peroxide left from the catalase lab last week.  (Peroxide breaks down fairly quickly—which is why it’s in a brown bottle.  Light breaks it into water and oxygen.). So, Elepahnt’s toothpaste it is.  There’s a twist.  I’m going to show the class the reaction without telling them the amounts of yeast, water, hydrogen peroxide, or dish soap.  (Don’t dilute the hydrogen peroxide!). The kids are going to set up different trials to see which combination delivers the best foaming results.  I plan to warn them if they just dump materials they’ll earn a zero.  Oh, and anyone not wearing their safety glasses has to clean up the entire lab, not just their station.  Next week, we need to test.  I’ll post pix on Tuesday.

Update:  The lab went better than expected.  Next Tuesday, we'll review how to write a lab report. Here are the pix.

Apologia Biology: Cells: Catalase Lab

This week the class has done the Catalase Lab both days.  The concept is important.  Catalase is an enzyme in peroxisome organelles in the cell.  Its job is to break down hydrogen peroxide, a type of waste in the cell.  Yeast produces catalase.  But, the reason I'm doing this lab is to practice lab skills: names of equipment, how to measure, weigh, read volume, controlled variable, hypothesis, graphing.etc.  The list is long.  The particular emphasis was on controlled variables: the amount of yeast, the water temperature, duration to soak discs in yeast solution, etc.  The kids did the same lab twice.  Today, I had four of the girls (who had nearly finished Tuesday) work with different groups to help get them on track.  I also switched two groups.  I think I have good partners now.  Now, after three hours of lab, most of the kids have data to graph.  Tuesday, we're going to review the graphs, answer the questions, and discuss the Claim-Evidence-Reasoning strategy for the lab.  Here are a few photos.

Apologia Biology: Module 6 Cells: Gummy Bear Lab

Well, today was less chaotic.  Our class is one hour and 15 minutes twice a week.  We spent half of today's class weighing the gummy bears which had soaked for two days.  At the beginning of class, I went over a chart listing the average mass of the gummy bears before and after soaking in the salt solutions.  (Gummy Bear Osmosis Lab)  I had to explain how to average the data, how to calculate the percent change in the mass of the gummy bears, and how to graph a line graph.  Everyone has to create a bar graph with the mass before and after of the gummy bears by concentration.  Yes, this took all class period.  The kids have not had much lab experience or experimental design.  So, next class is another lab: How does concentration affect the reaction rates of enzymes?  The kids need another chance to set up, conduct, and graph the lab results.

Apologia Biology: Cells and Labs

Wow.  We have had two labs to understand cell processes: How Can Diffusion Be Observed? and Effect of Osmosis on Gummy Bears in Salt Solutions.  Yesterday, we spent half of class reviewing the Osmosis lab with cornstarch, baggies, and iodine.  Two kids missed the lab so I recreated the experiment for them before class.  We spent 35 minutes answering the lab questions as I used the baggie of cornstarch slurry in the iodine solution as a prop with these notes on Osmosis, hypotonic, hypertonic, and isotonic definitions.  One mom added a squirt of iodine to some cornstarch to show how iodine indicates starch as it turns black.  Because our discussion took so long the cornstarch slurry in the cup changed from black at the edges to a diffused purple in the bag over time.

Then we started the Gummy Bear Osmosis lab.  Wow.  I had no idea weighing salt and measuring water in a cylinder would be an issue—to say nothing about setting up controlled variables and number of trials.  The gummy bears need to sit for two days.  I assigned each group a different color of bears and added them to six containers to soak. (They’re in my garage soaking until Thursday.) I added plain distilled water to the containers of salt solutions as a controlled variable.

Clearly, we need more lab experience measuring, graphing, and experimental design.  So, we’re going to do an Enzyme Lab next.  Say a little prayer!

Apologia Biology: Cell Agenda

I thought I should give you an idea of the scope for Module 6, Cells.  It’s a big topic.  We’re working toward two tests: cell organelles and cell processes.  I start with plant and animal cell models and coloring sheets to introduce organelles.  The kids need to be able to identify and understand the structure and functions of key cell organelles: mitochondria, Golgi, nucleus, endoplasmic reticulum, chloroplast, lysosomes, ribosomes, vacuoles, chloroplast, cell membrane, vesicles, and cell wall.  Here are the key concepts:
1. Cell structure and function (organelles)
2. Prokaryotes vs. Eukaryotes
3. Animal vs. Plant cells
4. Osmosis vs. Diffusion
5. Cell movement
6. Microscope Basics
7. Intro to Diseases

We aren’t doing protein synthesis yet.  We will do some work on cell transport.  I plan to have one test on organelles and another on cell functions and processes.

Apologia Biology: Module 6, Osmosis, and Disease Transmission.

Our Co-op class is working through Module 6.  We started with a quick review of prokaryotes and eukaryotes, animal and plant cells, A Bag of Diseases, and an overview of the day’s agenda.  We started class with Sweet Sixteen Cell Tournament (another chance to become familiar with cell terms)—(The final answer is peroxysome.). The kids used their devices to locate the answers.  It took about 35 minutes—longer than I had expected.  Next, we set up the Osmosis Lab.  I brought large yogurt containers, cornstarch, iodine, pipettes, and baggies.  (Use cheap baggies.). The kids used warm water and about 25 drops of iodine, instead of ten.  More iodine is better.  The kids mixed a teaspoon of cornstarch into about 1/2 cup of warm water in the cheap, plastic baggie before sealing it.  Next, they added many drops of iodine to half a large yogurt container of warm water.  The kids let their lab experiments on the table for 20 minutes or so.  While the osmosis Lab was working, we did The Glo Germ Lab and Contagion Lab.  The Glo Germ Lab requires a black light, available for about $5-7.  The Glo Germ Mini Kit is only $11 and includes a black light.  I sprinkle a little Glo powder on the table and demonstrate how the germs glow under  us light.  Next, I have the kids rub Glo lotion on their hands and send them to the washroom to wash.  After, I scan their nail beds and wrists to show the kids where they missed.  They all wash again and I check again with the UV flashlight.  Contagion is also fun.  Everyone has a cup of water.  I slipped one kid a cup of water with NaOH, a base.  Everyone else has plain water.  The kids exchange small amounts of water with each other.  No one drinks the water.  After one minute, I squirt phenolthalein into everyone’s cup, saving the original cup for last.  Phenolthalein is a base indicator.  Children who swapped with the contaminated cup are pink.  I should have put in more base or used less water.  Anyway, the point is to visually drive home two prime means of disease transmission.  Lastly, we observed our Osmosis lab.  Time ran out before we could debrief the lab well.  I plan to do Gummy Bear Diffusion on Tuesday.  We need to explain hypertonic, hypotonic, and isotonic solutions before we review the Osmosis lab.  It was an unusually productive day.

Apologia Biology: Module 6 Cells, Prokaryotic vs. Eukaryotic

Today, we microscope labeling quiz. (answer key), assigned the Bag of Diseases project, and completed the POGIL Prokaryotic and Eukaryotic activity (answer key). Woooooo!  Last class, we introduced the kids to the microscope.  Today’s quiz was a repeat.  Yes, I did a review at the beginning of class.  Next, I distributed names of diseases to the kids, such as anthrax, TB, measles, pinworm, scabies, elephantitis, monkeypox, smallpox, Ebola, plague, boils, MRSA, etc.  The kids have two weeks to answer the Bag of Disease questions with images of the disease and pathogen to present to the class.  I specified that the images must be appropriate, i.e. not images of someone’s groin.  Lastly, the kids took about 50 minutes to complete the POGIL activity.  POGIL is unique.  All the information is present; the kids work together using the diagrams or charts to answer the questions.  My goal was to help the class to understand the differences between prokaryotic and eukaryotic cells.  The activity uses analogies, charts, and probing questions to hammer home the differences.  I took a couple of photos of the kids engaged.  Isn’t the library room fabulous?  Yes, there are always random people using the copier, wandering through to see the fish tank, or just curious what is going on.  Some of the kids like to go out into the hall for some quiet. 

Apologia Biology: Food Webs and Why I love Home-Schoolers!

This week, one of my favorite elementary student came running into the library with his food web.  Now, this child is eight; his brothers and sister are in Biology and Physics.  He loved the idea about food webs so much, he created one of his bed toys and drew me a diagram.  Now, that's what makes home-schooling exceptional; the children learn for the sake of joy.

Apologia Biology: Microscope 101

Today, I brought in eight microscopes, a quiz labeling the parts of a microscope, and a slideshow about cell, theory, and structure.  I started with a crash course in how to use a microscope correctly.  We did a quick overview of the parts of a microscope.  The kids had to use the microscopes to draw and label three microscope slides.  I have different microscopes; the kids rotated to try all of them.  After about 40 minutes, we had another review and quiz labeling the microscope. We graded the quiz in class.  I plan to quiz them again on Tuesday.   Lastly, we did a 15 minute intro to cells.  Today was unusually productive.  Take a look at the second photo; the digital microscope achieves 250 magnification.  For $34, this type of magnification is usually enough.  To install it, I plugged in the USB to the laptop and opened the camera.  Period.

Apolopgia Biology: Cell Models

The kids made plant and animal cell models.  I brought card stock, beans, beads, sequins, buttons, playdoh, chenille sticks, bottle caps, lids, plastic containers, etc.  They used diagrams, Inside the Cell,  and graphic images from their textbooks.  I don't like edible models.  They ooze or get crushed, distorting the organelles.  These two models and key are exceptional.

Apologia Biology: Cell Models

I need to teach my husband’s Physics class how to graph and do linear regression analysis with the graphing calculator.  He just taught them how to graph in Excel.  We used the graphing calculator in Chemistry last year.  I can use graphing calculators to explain linear regression in motion.  My husband, Rob, can switch with me and monitor my Biology class.  I’m going to have the kids make animal and plant cell models.  NIH has a free publication, Inside the Cell.  I don’t want edible models.  When a kid makes an edible model the jello cytoplasm inevitably oozes everywhere.  Yuck.  Instead, I have play doh, buttons, beads, beans, pipe cleaners, etc.  This rubric or guide specifies the organelles and requires both definitions and a key.  This is exactly what I want.