1. Chapter 2 Science, Matter, Energy, and System

2. Case Study: How do Scientists Learn about Nature? A story about a Forest Too see how an environmental change such as deforestation effects changes such as the loss of water and soil nutrients, a controlled field experiment can be held. First the environmental investigators could measure the amounts of water and dissolved nutrients in an uncut forest site, known as the controlled site, to see the measurements of the undisturbed matter. Secondly the uncut forest site could be changed into the experiment site by having the trees of the forest cut down causing deforestation then measuring the disturbed matter comparing it to the data of the undisturbed matter. The controlled matter would most likely reveal whether or not the experimental site did or did not effect the data.

3. 2-1 What do Scientists Do?

4. Science is a Search for Order in Nature Science is a human effort to discover how the physical world works by making observations and measurements, and carrying out experiments. Scientists use methods such as the scientific method to learn how the physical world works. Scientists collect data and develop theories and laws about how nature works. Scientific methods are used all the time in decision making.

5. Scientists Use Observations, Experiments, and Models to Answer Questions about How Nature Works There are eight formal steps in the Scientific Method. 1.Identify the Problem 2.Find out what is known about the problem 3.Ask a question to investigate 4.Collect data to answer the question 5.Propose a hypothesis to explain the data 6.Make testable projections 7.Test the projections with further experiments, models, or observations 8.Accept of reject the hypothesis Data is information needed to answer a question. Scientific Hypothesis is a possible explanation of what scientists observe in nature or in the results of their experiments. Models are an approximate representation or stimulation of a system. Scientific Theory is a well-tested and widely accepted scientific hypothesis or a group of related hypothesis.

6. Scientists Are Curious and Skeptical, and Demand Lots of Evidence There are four important features of the Scientific Process; curiosity, skepticism, reproducibility, and peer review. Good scientist are extremely curious but also skeptical of new data and hypothesis. Peer Review is when scientists openly publish details of the methods and models they used so that they could get the input of other scientists. Skepticism and debate among peers in the scientific community is vital for the scientific process.

7. Critical Thinking and Creativity are very Important in Science Scientists use logical reasoning and critical thinking skills to learn about the natural world. Thinking critically involves three important effects. 1.You have to be skeptical about everything you hear. 2.Look at the evaluated data of any related information and opinions and validate them. 3.Identify and evaluate your own personal assumptions, biases, and beliefs. Logic and critical thinking are very important tools in science; yet imagination, creativity, and intuition are vital.

8. Easter Island: Some Revision in a Popular Environmental Story Easter Island is always used as an example of how humans can seriously degrade their own life-support systems and civilization. For years the estimation was that about 2,900 years ago Polynesians came to Easter Island, there their population thrived increasing to about 15,000 people. With all the people there they cut down all their lush trees for resources. Now new data evaluation and research show that the Polynesians went to Easter Island about 800 years ago and the population only went up to 3,ooo. The trees however were lost and never grew back because the rats that came on the island ate all the seeds that would’ve grown.

9. Scientific Theory and Laws Are the Most Important and Certain Results of Science Facts an data are essential to science, their goals are too develop theories and laws based on the facts. When a large amount of observations and measurements supports a scientific hypothesis, it is known as a Scientific Theory. Scientific Theories are supported by extensive evidence since they have been tested widely. Scientific Theories are hardly overturned, unless new evidences result in scientist finding more logical explanations. Scientific Law/ law of nature are well tested and widely accepted descriptions of what is found repeatedly in nature in the same way. Scientific laws cannot be broken unless new data is discovered that lead to changes in the law.

10. The Result of Science Can Be Tentative, Reliable, or Unreliable Scientists always test their hypothesis, models, methods and results several times; testing is a fundamental part of science. Tentative/ frontier science is when results are not considered reliable yet. Reliable Science consists of data, hypothesis, models, theories, and laws that are widely accepted by al l or most of the scientists who are known as experts. Unreliable Science is when results are presented at reliable yet it didn’t go through peer review.

11. Science Has Some Limitations Science in general such as Environmental has five important imitation. 1.Scientist cannot prove nor disprove anything absolutely since there is always some degree of uncertainty in the data. 2.Since scientists are humans they are entitled to their own biased opinions and hypothesis. 3.Many systems in the natural world involve a huge number of variables with complex interactions. 4.Science involves different tools, and sometimes it is impossible to measure things so they estimate some measurements. 5.It I limits to understanding the natural world. Despite these five limitations, science is the most useful way we learn about how nature works.

12. Science Focus: Statistics and Probability Statistics consists of mathematical tools that we can use to collect, organize, and interpret numerical data. Probability is the chance that something will happen or will be valid. Example in a coin toss the probability you land on heads is 50% and the probability you will land on tails is 50%. Most of the time situations will have a 50/50 probability having variation in the results.

13. 2-2 What is Matter?

14. Matter Consists of Elements and Compounds Matter is anything that has mass and takes up space. Matter can exist in three different states; solid, liquid, and a gas. Elements are a fundamental type of matter that has a unique set of properties and cannot be broken down into simpler substances by chemical means. Compounds are combinations of two or more different elements held together in fixed portions.

15. Atoms, Molecules, and Ions Are Building Blocks of Matter An Atom is the most basic building block of matter. Atomic Theory is the theory that all elements are made up of atoms and is the most widely accepted scientific theory in chemistry. Electrons Protons and Neutrons are subatomic particles. Neutrons have no electrical charge, Protons have a positive electrical charge, and electrons have a negative electrical charge. Nucleus is an extremely small center which contains one or more protons an un most cases one or more neutrons. Atomic Number is equal to the number of protons in the nucleus of that atom. Mass Number is the total number of neutrons and protons in its nucleus. Isotopes have the same atomic number but different masses. Molecules are a second building block of matter and are combinations or two or more atoms of the same or different elements held together by chemical bonds. Ions are a third building block of some types of matter and are an tom or a group of atoms with one or more net or positive or negative charges. Acidity is a chemicals characteristic that helps determine how a substance dissolved in water will interact with and affect the environment. pH is used to measure acidity. Chemical Formulas are used to show the number of each type of atom or ion in a compound.

16. Organic Compounds are the Chemicals of Life Organic Compounds are plastics, as well as table sugar, vitamins, aspirin, penicillin, and most of the chemicals in our body. Inorganic compounds are all other compounds that are not organic. Some organic compounds include: 1.Hydrocarbons 2.Chlorinated hydrocarbons 3.Simple Carbohydrates The three major types of organic polymers are: 1.Complex carbohydrates 2.Proteins 3.Nucleic Acid

17. Matter Comes to Life through Genes, Chromosomes, and Cells Cells are the fundamental structural and functional units of life. Genes are certain sequence of nucleotides in DNA molecules. Traits are characteristics that are passed one from parents to offspring during reproduction of an animal or plant. Chromosomes are made up of thousands of genes.

18. Some Form of Matter are More Useful then Others Matter Quality is a measure of how useful a form of matter is to humans as a resource, based on its availability and concentration. High Quality Matter is highly concentrated and is typically found near the earth’s surface and has a great potential for use as a resource. Low Quality Matter is not highly concentrated and is often located deep underground or dispersed in the ocean or atmosphere and it usually has little potential for use as a resource. Matter consists of elements and compounds that in turn are made up of atoms, ions, or, molecules.

19. 2-3 What happens when matter undergoes change? Concept 2-3: Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed.

20. Matter undergoes physical, chemical, and nuclear changes. When matter undergoes a physical change there is no change in its chemical composition. (ice cube melting into water). When a chemical change takes place there is a change in its chemical composition. (frying an egg). In addition to physical and chemical change matter can undergo nuclear change. (radioactive decay, nuclear fission, nuclear fusion).

21. We cannot create or destroy atoms: The Law of Conservation of matter. Scientific Law: Law of Conservation of matter: Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed. All we can do is rearrange the atoms, ions, or molecules, into different spatial patterns (physical change) or chemical combinations (chemical change)..

22. 2-4 What is energy and what happens when it undergoes change? Concept 2-4 A: Whenever energy is converted from one form to another in a physical or chemical change, no energy is created or destroyed (first law of thermodynamics). Concept 2-4 B: Whenever energy is converted from one form to another in a physical or chemical change, we end up with lower quality or less usable energy than we started with (second law of thermodynamics).

23. Energy comes in many forms. Energy: the capacity to do work or transfer heat (work=force x distance) Work is done when any object is moved a certain distance. Two major types of energy: moving energy (kinetic energy such a flowing water or heat) and stored energy (potential energy). Electro magnetic radiation is kinetic energy in which energy travels in the form of a wave (X rays). If you hold a book in your hand and then drop it it has potential energy before it is dropped.

24. Some types of energy are more useful than others. Energy quality is a major of capacity of as type of energy to do useful work High quality energy has a great capacity to do useful work because it is concentrated (very high temperature heat, sunlight energy released when coal or gasoline is burned Low quality energy is energy that has little ability to do high quality work.

25. Energy Changes are governed by two scientific Laws. See concepts on first 2-4 slide

26. 2-5 What are systems and how do they respond tochange? Concept 2-5: Systems have inputs, flows, and outputs of matter and energy, and feedback can affect their behavior.

27. Systems have inputs, flows and outputs. A system is a set of components that function and interact in some regular way (human body, river, economy). Most systems have following key components: inputs from environment, flows or throughputs from matter within system, and outputs to the environment.

28. Systems respond to change through feedback loops. Feedback is any process which increases or decreases a change to a system. A feedback occurs when an output of matter, energy, or information is fed back into the system as an input and leads to change in that system. A positive feedback loop causes a system to change further in the same direction. A negative feedback loop causes a system to move in the opposite direction of which it is going (recycling).

29. 2-5 Science Focus The usefulness of models. Scientists use models or simulations to show systems work and mathematical models are especially useful when there are many interacting variables..After building and testing a model scientists can use it to project what is likely to happen under a variety of conditions. Climate change, deforestation, biodiversity and oceans are important areas of economics that use models.

30. It can take a long time for a system to respond to feedback. A complex system will often show a time delay or lack of response during a period of time between input of a feedback stimulus and the systems response to it. Tipping point: the point at which a fundamental shift in the behavior of a system occurs.

31. Systems affects can be amplified through Synergy. A synergistic reaction or synergy occurs when two or more processes interact so that the combined effect is greater than the sum of their separate effects. Can be unhelpful (smoking and inhaling asbestos) or helpful (running with a partner).