Grade 10 Science Climate Change
Grade 9 Academic Science – Ecosystems (Section 2.1)
Canned Heat
Teacher Notes
Hypothesis - Different coloured objects absorb energy at different rates. That is partially due to albedo. Albedo is the amount of reflection from a surface.
Materials
· Two empty coffee cans
· Thermometer
· "Flat Black" spray paint - One coffee can must have a shiny metallic surface inside and out. The other can should be painted flat black inside and out.
Methods
· Fill the two cans with about 5 cm of water.
· Measure the temperature of the water in each can. (NOTE: The readings should be the same.)
· Remove the thermometer and place the cans in a sunny location where they will not be disturbed and receive two hours of sunlight.
· After a pre-determined time period, measure the temperature of the water in each can.
Discussion
The darker and duller the object, the more energy that object absorbs. The lighter coloured or the shiner the object is, the less energy that its absorbs. Since more energy was reflected from the shiny can, less energy is absorbed than in the black painted can. But how does the water become warmer?
The water is heated by the energy emitted by the cans. Some objects, like glass, seem to absorb light hardly at all-the light goes through. For a shiny metallic surface, the light isn't absorbed either, it gets reflected. For a black material, light and heat are almost completely absorbed.
Heated bodies radiate energy, operating in reverse. The more an object absorbs, the more it radiates. The water in the shiny can was not as warm as in the black can because it absorbed less energy and therefore has less energy to radiate into the water. This is called "black body radiation".
Grade 10 Science – Climate Change
It’s a Gas
Teacher Notes
Carbon dioxide (CO2) has increased greatly in the atmosphere over the past 100 years. Although it comprises only 0.03% of the atmosphere, CO2 has been linked to global warming.
Hypothesis: Carbon dioxide has an effect on temperature.
Materials
· Two (2) clear 2L bottles
· Two thermometers
· Moulding clay
· Two seltzer tablets
· Table top lamp used as a source of heat
Methods
1. Partially fill both bottles with water.
2. Add the seltzer tablets to one of the bottles.
3. Suspend the thermometers inside the bottles in such a way that you can measure the temperature of the air and seal the tops with moulding clay.
4. Place the lamp at equal distance between each bottle.
5. After an hour, measure the temperature of the water in each bottle.
Discussion
The seltzer tablets supplied one bottle with a source of carbon dioxide. The "fiz" will have heated faster and to a higher temperature than in the other bottle. The increase in heating ability is due to carbon dioxide's high capacity to hold heat.
It has been thought that an increase in carbon dioxide will lead to global warming. While carbon dioxide in the atmosphere has been increasing over the past 100 years, there is no evidence that it is causing an increase in global temperatures. NOTE: In 1997, NASA reported global temperature measurements of the Earth's lower atmosphere obtained from satellites revealed no definitive warming trend over the past two decades. In fact, the trend appeared to be a decrease in actual temperature.
The behaviour of the atmosphere is extremely complex. Therefore, it is complex and difficult to discover the validity of global warming. How much effect will the increase in carbon dioxide have? It is unclear. Will we even recognize the effects of any increase?
Grade 10 Science – Climate Change
Canned Heat Laboratory
Hypothesis - Different coloured objects absorb energy at different rates. That is partially due to albedo. Albedo is the amount of reflection from a surface.
Materials
· Two empty coffee cans
· Thermometer
· "Flat Black" spray paint - One coffee can needs to have a shiny metallic surface inside and out. The other can should be painted flat black inside and out.
Methods
· Fill the two cans with about 5 cm of water.
· Measure the temperature of the water in each can. (NOTE: The readings should be the same.)
· Remove the thermometer and place the cans in a sunny location where they will not be disturbed and receive two hours of sunlight.
· After a predetermined time period, measure the temperature of the water in each can.
It’s a Gas Laboratory
Carbon dioxide (CO2) has increased greatly in the atmosphere over the past 100 years. Although it comprises only 0.03% of the atmosphere, CO2 has been linked to global warming.
Hypothesis: Carbon dioxide has an effect on temperature.
Materials
· Two (2) clear 2L bottles
· Two thermometers
· Moulding clay
· Two seltzer tablets
· Table top lamp used as a source of heat
Methods
1. Partially fill both bottles with water.
2. Add the seltzer tablets to one of the bottles.
3. Suspend the thermometers inside the bottles in such a way that you can measure the temperature of the air and seal the tops with moulding clay.
4. Place the lamp at equal distance between each bottle.
5. After an hour, measure the temperature of the water in each bottle.