Activity 1: Cellular Respiration and Carbon Dioxide
Integration Notes: Mountain climbing requires a great deal of muscular activity. Muscles can only do work when they contract and contracting muscles require a great deal of energy. This energy is obtained through the process of cellular respiration.
During this process, carbon dioxide is released by the muscle cells as a waste product. Carbon dioxide is very toxic to the human body and must be excreted quickly.
When carbon dioxide is added to water it forms a weak acid called carbonic acid. Carbonic acid lowers the pH of the solution making it more acidic. If muscle activity is high, like it is when climbing a step slope, more carbon dioxide will be produced. This excess carbon dioxide must be eliminated quickly or the pH of the blood will become too acidic.
An indicator is a chemical that is used to indicate the presence of another substance. Bromothymol blue is an indicator that is blue in a neutral substance such as water. In the presence of an acid, bromothymol blue turns from green to yellow depending on the pH of the solution.
Learner Outcome:
Conduct a test to determine if carbon dioxide is present in exhaled air.
Observe the colour change of bromothymol blue in the presence of carbonic acid (carbon dioxide dissolved in water).
Materials:
Glass flask or tall glass jar
Two plastic straws per person
1 per cent bromothymol blue solution
Activity Instructions:
1. Add 100 ml of bromothymol blue solution to the glass flask or tall glass jar.
2. Place the two straws into the flask or jar.
3. Breathing normal, inhale through your nose and exhale through the straws into the bromthymol blue solution. The exhaled air should bubble gently in the solution.
4. Continue breathing in this fashion. Do NOT force breathing and be sure that all exhaled air goes through the straws into the solution.
5. Record your observations.
6. When you are finished, make sure to dispose of your straws properly.
7. Explain how this activity shows carbon dioxide is produced in the human body.
8. What could you change in this procedure to make sure bromothymol blue changes colour in the presence of an acid?
Extension Ideas:
Design and do an investigation that would compare the amount of carbon dioxide produced at rest to the amount of carbon dioxide produced during exercise. Another activity might be to design an investigation to determine the effect of temperature on cellular respiration using microorganisms such as yeast cells.
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Integration Notes: This activity is designed to get students thinking about how Byron and other members of the expedition use special tents to protect themselves from the elements.
The Everest 2000 expedition will be using a geodesic tent designed to withstand winds over 100 km/h and survive being completely buried under snow.
A geodesic dome is a specialized system of trusses that transfers the load of structure equally and uniformly to all members of the structure. These domes, built on the principle of tensegrity, do not use supporting columns. Domes use triangular shapes that are connected to transfer the load. They are also designed to provide the lateral strength within a sphere until the structure connects to the ground.
Many schools will be involved in the Everest 2000 telecollaborative project 'Getting to Know You.' During Phase 2, students could continue collaborating with their telecollaborative groups as they try to come up with a tent design.
Learner Outcomes:
Students will:
Design a geodesic dome structure.
Compare their structures to those created by other students in Canada.
Materials:
Wooden stir sticks
Introduction/Purpose:
To design a structure that will withstand a specific load.
Activity Instructions:
1. Students are to design and construct a geodesic dome based on the design of the tents used by the Everest 2000 expedition.
2. Students should begin by conducting research on geodesic domes. A good place to start is to learn more about the architect Buckminster Fuller.
Design Requirements:
The dome must have a radius of between 14 cm and 15.5 cm at the base.
The dome must not exceed a mass of 110 grams.
Fastening of the members can be done with any materials available.
The dome may be covered with a light, transparent covering.
Testing:
Students should construct their own model.
Test the structure by suspending a mass from the center of the dome. Testing should begin at 100 grams and be increased in 10 gram increments.
Record the load that was supported before the structure failed. For example, the structure being tested held a load of 200 grams but failed under a 210 gram load. The student would record the 200 gram load.
Share your design and results with other groups if you are involved in the Everest 2000 telecollaborative project.
Extension Ideas:
Teachers can adjust the dimensions and mass of the structure to make it more challenging. Teachers can set up a "play-money" bank and have students buy all of the materials they are going to use in the project. This will help to cut down waste and might make the project a bit more meaningful for the students.
