a tree grows and increases its mass. explain why this
TRANSCRIPT
Science, Systems, Matter and EnergyMatter
•A tree grows and increases its mass. Explain why this phenomenon is not a violation of the law of conservation of matter
Energy
• Someone wants you to invest money in an automobile engine, claiming that is will produce more energy than the energy in the fuel used to run it. What is your response? Explain.
Scientific Method
• Respond to the following statement:
• The natural greenhouse theory – that certain gases such as water vapor and carbon dioxide warm the lower atmosphere – is not reliable idea because it is just a scientific theory.
Science, Systems, Matter and Energy
Chapter 2
Key Concepts
• Appropriate experimental design is essential for conducting sound scientific investigation.
• The chemistry of several key elements is central to the study of the environment.
• Energy flow, conversions, and degradation are governed by the laws of thermodynamics.
• Environmental systems and feedback can be used to simplify and model complex relationships.
Science
• Seeks to understand the natural world for the greater benefit of society via the scientific method
• Observation –
• Problem statement –
• Ex. How does the loss of water and nutrients from a pristine forest compare to a stripped forest?
• Hypothesis – an educated guess
• Experimental group –
• Control group –
• Independent variable –
• Dependent variable –
• Control variables –
• Analysis of data – Compare data from control and experimental groups.
• Ex.
• Communicate results
• Repeat experiment
Science
• Scientific Theories and Laws Are the Most Important Results of Science • Scientific theory
• Widely tested
• Scientific law, law of nature
• The Results of Science Can Be Tentative, Reliable, or Unreliable
• Tentative science, frontier science
• Elements • Know the element symbol
and name for all listed on pg. 36 in text. Ex.
• Hydrogen (H)
• Oxygen (O)
Matter
Atoms
Matter
Isotopes
Matter
• Ions
• Know the symbol and name for all listed on pg. 37 in text. Ex. • Hydrogen ion
(H+)
Matter
Calculations of pH Example: Determination of pH from [H+]
• “p” stands for the negative log, so pH is the negative log of [H+]
+]
• pH = - log10 [1 X 10-4]
• pH = - [ log10 1 + log10 10-4 ]
• Note: When you multiply numbers you always ADD their log forms
• log10 1 is always zero and log10 10x = x
• so log10 10-4 = -4
Matter
Calculations of pH Using the equation pH + pOH = 14
Example: Calculate the pH of a solution that has a [OH1-] = 1 X 10-5 M • Determine pOH = -log[OH1- ] = -log [1 X 10-5 ] = 5
• Use the relationship pH + pOH = 14
• pH + 5 = 14
or more elements (exception – CH4)
• Hydrocarbons (CH4; Fossil fuels) and chlorinated hydrocarbons (DDT; C14H9Cl5)
• Simple carbohydrates (glucose)
• Proteins
• Lipids
Matter
• Compounds
• Know the symbol and name for all listed on pg. 37 in text.
Matter - Nuclear Changes
• Changes in particles in an atom's nucleus and thus a change in the atom itself.
• All elements heavier than bismuth (Bi) (and some lighter) exhibit natural radioactivity.
• Types of radiation: • Alpha Radiation (α) is the α particle which contains two protons and
two neutrons (similar to the 4 2He nucleus)
• Beta Radiation (β) is the emission of the electron from the atom's nucleus.
• Gamma Radiation (γ) involves the emission of electromagnetic energy (similar to light energy) from an atom's nucleus
Matter – Nuclear Changes
• Chain reactions are multiple fissions
• Fusion: fusing of more than one element (i.e: the Sun)
Matter – Nuclear Changes
• Half-life - The time needed for one-half of the nuclei radioisotope to decay and emit their radiation to form a new isotope
• General rule: 10 half- lives are needed before a radioactive element is at a safe level for humans • Uranium 235 common in
nuclear reactors has a half- life of 7.10 x 108 years
Matter – Law of Conservation
• Only changes form
• Chemical change = reaction
• Combustion of methane yields carbon dioxide and water Slide 16Slide 16
Reactant(s)
carbon dioxide + energy
C
O
O
pollutants
• Concentration
Energy
• Potential vs. Kinetic
What is Energy?
Slide 14Slide 14
Convection Conduction Radiation
Heating water in the bottom of a pan causes some of the water vaporize into bubbles. Because they are lighter than the surrounding water, they rise. Water then sinks from the top to replace the rising bubbles. This up and down movement (convection) eventually heats all of the water.
Heat from a stove burner causes atoms or molecules in the pan Õs bottom to vibrate faster. The vibrating atoms or molecules then collide with nearby atoms or molecules, causing them to vibrate faster. Eventually, molecules or atoms in the pan Õs handles are vibrating so fast it becomes too hot to touch.
As the water boils, hear from the hot stove burner and pan radiate into the surrounding air, even though air conducts very little heat.
Energy Comes in Many Forms
• Sun provides 99% of earth’s energy
• Warms earth to comfortable temperature
• Plant photosynthesis
• And the remaining 1%?
Slide 15Slide 15
Dispersed geothermal energy
(usefulness)
• First Law of Thermodynamics • Law of conservation of energy
• Energy is neither created nor destroyed in physical and chemical changes
• Second Law of Thermodynamics • Energy always goes from a more useful to a less
useful form when it changes from one form to another (entropy increases)
• Light bulbs and combustion engines are very inefficient: produce wasted heat • Light bulbs only 5-10% efficient
• Combustion engines only 6% efficient
Complex Issues
• Negative Feedback • Thermostats
2. You cannot get something for nothing.
3. You cannot break even.
•A tree grows and increases its mass. Explain why this phenomenon is not a violation of the law of conservation of matter
Energy
• Someone wants you to invest money in an automobile engine, claiming that is will produce more energy than the energy in the fuel used to run it. What is your response? Explain.
Scientific Method
• Respond to the following statement:
• The natural greenhouse theory – that certain gases such as water vapor and carbon dioxide warm the lower atmosphere – is not reliable idea because it is just a scientific theory.
Science, Systems, Matter and Energy
Chapter 2
Key Concepts
• Appropriate experimental design is essential for conducting sound scientific investigation.
• The chemistry of several key elements is central to the study of the environment.
• Energy flow, conversions, and degradation are governed by the laws of thermodynamics.
• Environmental systems and feedback can be used to simplify and model complex relationships.
Science
• Seeks to understand the natural world for the greater benefit of society via the scientific method
• Observation –
• Problem statement –
• Ex. How does the loss of water and nutrients from a pristine forest compare to a stripped forest?
• Hypothesis – an educated guess
• Experimental group –
• Control group –
• Independent variable –
• Dependent variable –
• Control variables –
• Analysis of data – Compare data from control and experimental groups.
• Ex.
• Communicate results
• Repeat experiment
Science
• Scientific Theories and Laws Are the Most Important Results of Science • Scientific theory
• Widely tested
• Scientific law, law of nature
• The Results of Science Can Be Tentative, Reliable, or Unreliable
• Tentative science, frontier science
• Elements • Know the element symbol
and name for all listed on pg. 36 in text. Ex.
• Hydrogen (H)
• Oxygen (O)
Matter
Atoms
Matter
Isotopes
Matter
• Ions
• Know the symbol and name for all listed on pg. 37 in text. Ex. • Hydrogen ion
(H+)
Matter
Calculations of pH Example: Determination of pH from [H+]
• “p” stands for the negative log, so pH is the negative log of [H+]
+]
• pH = - log10 [1 X 10-4]
• pH = - [ log10 1 + log10 10-4 ]
• Note: When you multiply numbers you always ADD their log forms
• log10 1 is always zero and log10 10x = x
• so log10 10-4 = -4
Matter
Calculations of pH Using the equation pH + pOH = 14
Example: Calculate the pH of a solution that has a [OH1-] = 1 X 10-5 M • Determine pOH = -log[OH1- ] = -log [1 X 10-5 ] = 5
• Use the relationship pH + pOH = 14
• pH + 5 = 14
or more elements (exception – CH4)
• Hydrocarbons (CH4; Fossil fuels) and chlorinated hydrocarbons (DDT; C14H9Cl5)
• Simple carbohydrates (glucose)
• Proteins
• Lipids
Matter
• Compounds
• Know the symbol and name for all listed on pg. 37 in text.
Matter - Nuclear Changes
• Changes in particles in an atom's nucleus and thus a change in the atom itself.
• All elements heavier than bismuth (Bi) (and some lighter) exhibit natural radioactivity.
• Types of radiation: • Alpha Radiation (α) is the α particle which contains two protons and
two neutrons (similar to the 4 2He nucleus)
• Beta Radiation (β) is the emission of the electron from the atom's nucleus.
• Gamma Radiation (γ) involves the emission of electromagnetic energy (similar to light energy) from an atom's nucleus
Matter – Nuclear Changes
• Chain reactions are multiple fissions
• Fusion: fusing of more than one element (i.e: the Sun)
Matter – Nuclear Changes
• Half-life - The time needed for one-half of the nuclei radioisotope to decay and emit their radiation to form a new isotope
• General rule: 10 half- lives are needed before a radioactive element is at a safe level for humans • Uranium 235 common in
nuclear reactors has a half- life of 7.10 x 108 years
Matter – Law of Conservation
• Only changes form
• Chemical change = reaction
• Combustion of methane yields carbon dioxide and water Slide 16Slide 16
Reactant(s)
carbon dioxide + energy
C
O
O
pollutants
• Concentration
Energy
• Potential vs. Kinetic
What is Energy?
Slide 14Slide 14
Convection Conduction Radiation
Heating water in the bottom of a pan causes some of the water vaporize into bubbles. Because they are lighter than the surrounding water, they rise. Water then sinks from the top to replace the rising bubbles. This up and down movement (convection) eventually heats all of the water.
Heat from a stove burner causes atoms or molecules in the pan Õs bottom to vibrate faster. The vibrating atoms or molecules then collide with nearby atoms or molecules, causing them to vibrate faster. Eventually, molecules or atoms in the pan Õs handles are vibrating so fast it becomes too hot to touch.
As the water boils, hear from the hot stove burner and pan radiate into the surrounding air, even though air conducts very little heat.
Energy Comes in Many Forms
• Sun provides 99% of earth’s energy
• Warms earth to comfortable temperature
• Plant photosynthesis
• And the remaining 1%?
Slide 15Slide 15
Dispersed geothermal energy
(usefulness)
• First Law of Thermodynamics • Law of conservation of energy
• Energy is neither created nor destroyed in physical and chemical changes
• Second Law of Thermodynamics • Energy always goes from a more useful to a less
useful form when it changes from one form to another (entropy increases)
• Light bulbs and combustion engines are very inefficient: produce wasted heat • Light bulbs only 5-10% efficient
• Combustion engines only 6% efficient
Complex Issues
• Negative Feedback • Thermostats
2. You cannot get something for nothing.
3. You cannot break even.