Core Biology Classes Enzyme Activity Analysis

          Traditionally, the Core Biology classes examine the factors that affect the activity of the enzyme catalase. Catalase is a common enzyme found in liver, potatoes and turnips.

          It catalyzes the conversion of hydrogen peroxide into hydrogen gas and oxygen gas. Mrs. Bastone's class used the Vernier Oxygen probes and the Labquest2 tablets to gather their data. They had some trouble getting meaningful results. Not all of the groups were able to calibrate their probes. Apparently the electrodes that sense the presence of oxygen have a limited life and eventually are not sensitive enough to pick up the voltage changes caused by the presence of oxygen on their surfaces.

          Ms. Davies' class used the Vernier Gas Pressure probes in place of the Oxygen probes and all of her groups got better results when measuring the pressure within their reaction vessels as the oxygen gas built up over time. Mrs. Bastone plans to repeat the experiment with the Gas Pressure probes after the Spring Recess.

          In both classes the students altered an established protocol to examine different factors that might affect the amount of gas produced overtime. Some of the independent (manipulated) variables used by the students in their experiments were: temperature (room temp, above room temp, below room temp), pH (acidic, neutral, basic environments) and catalase sources (beef liver, calf's liver, chicken liver, apples, strawberries and potatoes).

The weighing dishes in front of the boiling water bath contain a strawberry in one and pieces of potato in the other. This lab group was comparing the gas production from these two sources of catalase. The student also appears to be preparing a test tube of enzyme source to be boiled to see the effect of high temperatures on enzyme activity.

One can clearly see the the bubbling gas produced when macerated beef liver is added to the hydrogen peroxide in the reaction vessel. In the lower right hand corner of this picture you can see a printout from one of this group's previous runs.

Science Seminar April 3

Science Seminar Series

Presents

Naomi Schwartz

Doctoral student, Columbia University

Understanding the causes and effects

 of fire in the Peruvian Amazon

In recent years, wildfire activity has increased across the Amazon. In the past, fire was very rare there, so these changes could have big effects on biodiversity, ecosystems, and the carbon cycle. Most fires in the Amazon are started by people, either intentionally, through the use of fire for land management, or accidentally. Especially during drought years these fires can burn out of control into nearby forests. Naomi Schwartz is a Ph.D. student in ecology, evolution, and environmental biology at Columbia University. Her work uses a combination of ground and satellite measurements to understand the causes and effects of these fires in the Peruvian Amazon. She is especially interested in understanding the relationships between human activities and fire occurrence, and the effects of fire on secondary forests.

Wednesday, April 3

7 pm

Bronxville High School Auditorium

Middle School Science Olympiad Team

Middle School Science 2012-2013 Olympiad Team

 
On Saturday, March 2 the Middle School Science Olympiad team competed in the Lower Hudson Valley competition at Scarsdale Middle School. Congratulations to all the team members and their coach, 8th Grade Team Leader Jean Windels.

Anton and Zip are pleased with their medal win in the "Mission Possible" - competition in which they had to design and build a "Rube Goldberg device

Kenny and David with their flying helicopter.

Kenny and Michael snagged a first place medal for their performance in the "Dynamic Planet" event in which they answered questions about glaciers.

Buz and Emmet won a medal for the "Helicopter Egg Drop" event, in which the students had to design a device that could drop an egg from a height of 8 meters without breaking the egg.

Michael and Jason received second place medals for the "Road Scholar" event in which they were required to read and answer detailed questions about the information present on a road map and a topographic map.

Sasha and Kirsten also won medals for the "Helicopter Egg Drop" event.

Kenny and Michael agreed to pose for this picture to display the back of the team "uniform" T-shirts.

Kenny and David in the process of flying their helicopter.

Chem II Freezing Point Depression Analysis

The Chem II students use differences in freezing point depression of three unknown water solutions A, B and C to determine which of the solutions contain sodium chloride, calcium chloride, and sucrose as the solute, in this lab exercise presented by Mr. Nowak.  Once that is determined they will be able to calculate the molality of each solution from the data they collected. The students do know that each solution has the same concentration.

James and Bailie use temperature probes to determine the temperature of three unknown solutions as they approach their freezing points, as Matthew and Jordan look on.

Kenny and Max look on as Mr. Nowak checks their set up.

Alina, Malika and Tatiana decided to use three separate ice baths to bring their solutions down to their freezing points, as Professor Maitland observes their technique during her classroom visit.

The Labques2t Tablet indicates each of the three probes using a different background color. The probes are showing the temperatures of the three solutions (A, B and C) as they approach their freezing points.

United States Coast Guard Summer Program

The United States Coast Guard is offering this one week program for high school juniors who may be interested in attending the Coast Guard Academy for college.

   USCG Summer Program by Charles Ippolito

Biome Displays by Environmental Science Class

"Biomes are defined as the world's major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment" (Campbell, N.A. 1996. Biology, Fourth Edition. The Benjamin/Cummings Publishing Company, Inc. Menlo Park, CA.).

"The importance of biomes cannot be overestimated. Biomes have changed and moved many times during the history of life on Earth. More recently, human activities have drastically altered these communities. Thus, conservation and preservation of biomes should be a major concern to all." (http://www.ucmp.berkeley.edu/glossary/gloss5/biome/)

As an introduction to their unit on Global Warming/Climate change students in the class researched and produced posters on each of the major biomes found on Earth. The students then "visited" each station to examine and learn about each biome from their classmates, who prepared the posters.

Students were encouraged to document the posters for later study using their smart phones.

Environmental Science Climate Presentations

The environmental science class began their global warming unit of study by preparing and sharing displays describing the six major factors that contribute to climate. Pairs of student were each assigned a topic to prepare. The remaining students of the class then rotated through each station to learn about the factors.

Atmosphere Display

Coriolis Effect Display

Carbon Cycle Display

Green House Effect Display

Ocean Currents Display

Solar Radiation Display

Ethan explains how the Coriolis effect contributes to the climate of a particular region.

Alex uses her presentation to explain how the Carbon Cycle contributes to climate.

Asil clarifies the Green House Effect to his classmates.

Claire describes and explains the various layers the compose the atmosphere and how they affect climate.

Paul explains how climate is affected by solar radiation and the tilt of Earth's axis.

Students take notes as Sally explains how Ocean Currents affect climate.

Erin joins Ethan in debunking some common myths about the Coriolis Effect.