Soda can calorimeter by Flinn

In chemistry yesterday we set up the Soda can calorimeter experiment.  I found this set up a bit better than using a wire mesh sitting on top of the ring clamp. More heat was transferred to the can that way. The other modification that my colleague and I made was to use a watch glass and a large paper clip to put the food sample on for burning. The students really enjoyed the lab. I think everyone was fascinated to watch the cheeseballs go up in flames. The really do burn well compared to the marshmallows. Hopefully they will make the connection between the calories they consume and the unit of energy. The other nice thing about Flinn's write up is their easy to follow calculations set out step by step.

Particulate matter pollution

The ecology class took a look at pollution recently when we set out some PM (particulate matter) pollution detectors. Granted the EPA defines PM particles as between the range of 0-10 micrometers and what we captured is much larger but it gave us all an idea of the debris that is falling from the sky or being generated from the ground when disturbed by activity. So many of our students suffer from asthma that it is good to raise their awareness, and everyone else, of one of the many sources that can trigger an attack.

The detectors were made using a petri dish, a wax pencil to make a circle the size of a quarter, then a thin layer of petroleum jelly spread in the circle. We placed the detectors out for 48 hours and retrieved them. Unfortunately we had a rainstorm in between. I feared that would ruin our results but there was matter stuck in the petroleum jelly anyways. This is why you can see water droplets in the photos below. Under the dissecting scope (40x magnification) we could observe: dirt particles, pollen grains, tiny insects, and other debris. 

This detector was on the ground below an air exchange unit that is above on the roof.

Three of our detectors

Food for thought

In ecology class we have been discussing the human footprint and population growth. We watched National Geographic's Human Footprint which takes the viewer through the life of two individuals from birth to old age showing the lifetime amount of everyday items they consume (diapers, eggs, bananas, clothing, appliances, and the list goes on) and the amount of waste generated. This is an eye opener when you see all the cartons of milk you might drink in a lifetime all lined up.

This led us to looking at the wealth of the various regions of the world. I found the Food for thought activity in my researches. After some discussion of the material in our text, I divided up the class according to the instructions. One challenge was to calculate the percentages based on the number of students I actually have in class plus the use of empty chairs for a few of the absent students. We followed the discussion questions and it was very interesting to watch the students' reactions when I began to pass out the match sticks. Follow that up with the presentation of the chocolate kisses. When I asked "Asia" and "Africa" how they felt about "North America" and "Europe's" wealth, one student replied that she was "pissed" (American slang here for angry and not British slang).  That got the class talking.

One student remarked as she was leaving the classroom, "best class ever - movie and chocolate all in one period." I hope the lesson wasn't lost on her.

Need help with a lesson?

I've found a most helpful website in Teacher's Domain sponsored by Public broadcasting "and viewers like you." There you will find video clips, documents, interactive activities, lesson plans, and a whole lot more. What's nice to know is that even college professors are using this site as I experienced this summer while taking a very well thought out and organized online course offered by Fitchburg State University. I've been able to supplement my power point lectures with content rich video clips which are 3-5 minutes in length on average, and can serve as great conversation generators. I'm so glad to know that my annual membership to WGBH is going to serve a good cause namely me and my fellow teachers in the classroom. Not to mention the benefits to our students!

teachersdomain.org

With the start of a new school year, I am always looking for ways to freshen up old boring lesson plans. One tool that I have been using is video clips from the teachersdomain.orghttp://www.teachersdomain.org/ website. They have hundreds of videos, lesson plans, documents, and interactive activities available for use in your classroom. This week I have been teaching an overview of biology and using clips about evolution, form and function, and technology related topics such as genetic engineering and stem cell research. The site is free with a valid email and school affiliation. Give it a try!

Earth Day Collages

Earth Day fell on April 22nd this year which coincided with our last day before spring vacation and I was looking for a quick activity for my chemistry classes to do on this day that would have them focusing on how chemistry impacts the environment. I gave them a stack of magazines I had been collecting (National Geographic, Smithsonian, Wired, and Scientific American), a sheet of 11x17" paper, scissors, and glue sticks and said go to it and you must be done by the time the bell rings. Here are some examples of what they produced.

Energy Drinks and Cellular Respiration

Where do we living things get our energy from? Food of course which is broken down from the large polymers (carbohydrates, fats, or proteins) into their monomers. All of these monomers can then some how make their way into the Krebs or Citric Acid Cycle within the mitochondria of the cell. But is that the only way to get energy? What do students think? What about these Energy Drinks that are marketed and targeted especially at the age group I teach (high school)? Well let's take a look. A great web quest I found is called "A Can of Bull." It is a case study into a variety of products, their ingredients and how they work. Great place to start them looking, thinking, and talking about the use or misuse of Energy Drink Products.
I plan to follow up the web quest with having them research, read, and summarize a current event article about some aspect of energy drinks (health effects, marketing, regulating, etc). Then we will sit down for a Fishbowl discussion to share their findings and debate the topic.

1st Quiz and Lab

We had our first quiz today, and it wasn't so bad was it? We also performed our first lab. You had the opportunity to observe prepared slides of organisms from 4 different kingdoms (sorry protists, I didn't have any slides of your group today) the plants, animals, fungi, and bacteria.
Have a great weekend!

Homework: Complete questions 1-4 on the lab packet for Monday.

The Ten Themes and Microscopes

We have completed our outline of Chapter One, exploring the ten themes of Biology. We also took a look at the parts of the microscope. Tomorrow we will be having our short quiz on vocabulary terms and parts of the microscope. The second half of class will be devoted to working on looking at prepared slides of cells from plants, animals, and fungi.

Homework: Chapter review questions from page 20 numbers 1-10, 12, 15.

Day 2 - Friday

Today, we began outlining Chapter One. The key vocabulary words I defined for you were: biosphere, ecosystem, organism, cell, DNA, and species. We also looked at the characteristics of a mythical creature, the Whizzer, to determine if other unnamed organisms belonged to its species.
Homework: Read Chapter One, and log into the textbook website and register for the class (http://www.pearsonsuccessnet.com/) using the instructions on the colored sheet I gave you on the 1st day of class. Please let me know if you have any troubles. If you are able to get into the site, complete the WebQuest Activity for Chapter 1.

1st Day of School

Welcome back to school. I want to wish all of you a happy and successful school year. Today, I gave you lots of paperwork (sorry). Please make sure to read through it all. I will expect you to have your composition notebook and binder set up by Tuesday. Remember to sign up for the Internet access site for the textbook (the colored paper with the access codes).



After getting through introductions today, we did an observational activity. The challenge was to list characteristics that animals, plants, and seeds exhibit that lead us to think that they are living things. I also gave you a mystery item which stumped a lot of you. In the case of the mystery item more study was needed. Some of you suggested cutting it open to see what was inside. The mystery item turned out to be an oak gall (follow this link to learn more about it).



Homework for all classes (10 points): Have a parent/guardian sign both copies of the Safety Contract and return it tomorrow.

The Botany of Desire

I have just completed reading Michael Pollan's The Botany of Desire (Random House, 2001). In this book he takes a careful look at the relationship between humans and the plants that we have cultivated in particular: the apple, the tulip, marijuana, and the potato. The section on the potato might be worth exploring with students as it raises the question of whether or not we should bio-engineer the plants that we use to eat. At the time of publication, food labels were not required on bio-engineered products. Other topics worth exploring would be the large scale use of pesticides and herbicides and their impact on ground water and human health (particularly that of farm workers); the history of the Irish Potato Famine, and its impact on our country's development; organic farming techniques; and bioengineering techniques in plants and animals (including human gene therapy).

3-D Arthropod Models

When we completed our study of the 5 classes of Arthropod, I assigned a modeling project. Students could work independently or with one partner. They were to create a model of an Arthropod using recycled or craft materials, paying close attention to anatomical structure of the organism they were modeling. The following are websites that I provided them to help with their research: Insect Field Guide, Crustacean List, The Sea, Science Safari, eNature Field Guides, The Bug Guide, and The Garden Safari.

Worms, Worms, and More Worms

In our continuing study of the animal kingdom we have been studying three phyla of worms: Nematoda, Platyhelminthes, and Annelida. The Annelids include the gardener's best friend - the earthworm. I picked these nightcrawlers up at the local convenience store which carries live bait. Some of the students were a little grossed out by working with live worms.






The students began their studies of the earthworm by elliciting nervous system responses. In a dissecting tray the students laid dry and wet paper towels and placed the worms in the middle, covered them with a piece of cardboard and waited five minutes. The worms of course prefer a wet environment, and therefore moved to the wet paper towel side of the tray. Then with the tray covered completely with wet towels the students covered half of the tray with the cardboard and shined a flashlight on the worms. Worms like it dark so they beat a hasty retreat to the side of the tray that was covered by the cardboard.

Lastly, we set up a couple of "wormeries." We layered soil, sand, dead leaves, and some vegetable scraps (potato and apple peelings) in a two liter plastic bottle. Then we introduced 3-4 worms to each bottle. You can see the worms tunneling through this bottle (They are the pinkish layer right above the sandy layer). In order to provide the worms with the environment they prefer we have dark paper sleeves around the bottles to block the bright sunlight, and we keep the soil moistened.

To wrap it all up we have studied earthworm anatomy and conducted dissections. Many students were anxious about the dissections, but admit when it was all over it wasn't so bad.

New Unit - Animal Kingdom

Today, we introduced a new unit of study in class, the Animal Kingdom. At each lab station I placed samples of preserved animals, models, or skeletons of the various phylum (annelids, mammals, fish, amphebians, cnairdians, porifora, birds, arthropods and reptiles for example). The students went from station to station trying to name the group of animals, and to determine if the group were invertebrate or vertebrate animals. This was a sort of a K-W-L activity to see what the students knew about animals. We did not define what an invertebrate or a vertebrate was as this is a seventh grade class, and we really wanted to see what knowledge base they possess. The kids were definetely involved in this activity and exhibited high levels of interest. We currently have a pair of ringneck doves and several rats in the classroom which the students love to observe, care for, and interact with.

Baking Bread - A real world application

It is important for our students to understand why we study the curriculum that we do, and where will it apply in their everyday lives, therefore, as a follow up to our lesson and lab on yeast respiration, we made bread. I pointed out that for centuries we humans have been taking advantage of the process of yeast respiration for our own benefit. Yeast are used in baking, cheese and yogurt production, and in fermenting wine and beer. The emphasis in talking about the process of bread baking was on the requirements for yeast growth (food source, warmth, darkness, and moisture) and how the recipe fullfills these. I also stressed that the bread rises because of the carbon dioxide which is being released as the yeast cells respire. In a previous lab, the students had studied what yeast need to live by "proofing" yeast. They had set up a beaker with yeast and water (the control), and a second beaker with yeast, water and sugar (the experimental sample). They then made a wet mount slide of each sample, staining the yeast in order to see them and count them. The samples were then left overnight in a warm, dark place. The following day the students again prepared wet mount slides of each sample and discovered that sugar caused an increase in the number of yeast cells.

Studying Respiration in Yeast

In order to study respiration in yeast we set up an experiment using Bromothymol Blue (an indicator which is sensitive to the pH changes that result when carbon dioxide is dissolved in it), sugar, live yeast cells, and dead yeast cells (yeast were boiled). The students set up three test tubes with 15mL Bromothymol Blue solution and 2 grams of sugar. The first test tube served as a control containing only the Bromothymol Blue solution and sugar. The second tube had live yeast cells added to it, and the third had dead yeast cells added. The samples were then placed in a warm, dark room to incubate over night.















This lab group had an excellent result. From left to right the dead yeast tube, the live yeast tube and the control tube. Some lab groups had tubes that exhibited contamination in the dead yeast tube. Several groups had forgotten to clean their test tubes prior to beginning the lab. Lesson learned, never assume that your glassware is clean even if it looks clean. Of course we are not working under sterile conditions and some contamination is to be expected.

Edible Fungi Models

We made edible fungi models in class last Friday. The cardboard base represents a food source (tree branch, fruit, or piece of bread), the red and black licorice represent the hyphae, the tootsie pops standing are asexual spore cases, and the lollipop tops (orange in this model) represent sexual spore cases where +parent and -parent have met. The students had a blast making the models, and eating the extra modeling materials. If you can't get hold of shoe string licorice you may use two different colored yarns or ribbons.

Lichens

Lichens are a symbiotic relationship between fungi and either algae or photosynthetic bacteria (cyanobacteria). Yesterday and today we have been observing lichens in the classroom. For some students it has been hard for them to understand the concept that lichens are composed of two different organisms. One source of difficulty has been in preparing wet mount slides of crushed lichens. It is very easy to observe the algae, but harder to see the fungi hyphae. Any suggestions would be helpful.

International Space Station Viewing Opportunities

At school this morning the principal announced that in our area the International Space Station was scheduled to pass directly overhead and the sighting was expected to last up to 5 minutes. You can visit NASA to get information for sightings in your area. The station is best viewed at dawn or dusk when the sun is reflected off it. We took the opportunity to refresh the kids knowledge of how to use a compass in order to locate the station in the sky. Luckily, we had a compass for each student to use. Several students signed up to borrow a compass to use at home tonight. This was also a time to discuss NASA's future plans for space exploration and the role that the space station plays in endeavor.