Chapter 8, Lesson 1, "What is Work?"

Materials:

• Worksheet, 08-01, "What is Work?"

Objective:

• Students will define and explain work.
• Students will calculate an amount of work.

Drip the Metric System: Have each site select a student who will be the teacher today. Show the students a picture of a meterstick and have that student tell the others about it. Show a blow-up picture of the meterstick and have that student tell the others about it. Show the students a picture of a square meter and have the student tell the others about it. Show the students the picture of a cubic meter and have that student tell the others about it. Show the student a picture a cubic decimeter and of a liter and have the student relate that to the cubic meter. Show the students a milliliter and ask the student/teacher to relate that to a cubic centimeter and the liter. Show the students a gram and have them relate that to the milliliter.

Anticipatory Set:* Tell the students that a scientist would define work as work = Force x Distance. Show the students this picture and tell them that the force must be in the direction of the distance moved. If that is not the case no work is being done. With that in mind remind them of the pictures from yesterday and have them get out the sheet that they wrote on predicting whether work was happening. go through each with the formula on them. Is there work happening picture 1, picture 2, picture 3, picture 4, picture 5, picture 6, picture 7. Now for the tough one. Is work happening in this picture?

Teacher Input:* In the formula work equals force times distance we need to figure out what the units should be. Remember that a force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction. Do any of the students remember what the metric unit of force or weight is? Remind them of the Newton. Newtons can be measured with a spring scale. This spring scale does not really measure grams does anyone know why? One Newton is the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s. When measuring work distance is usually measured in the standard metirc unit of distance. What is that? So we have Work = Newtons x Meters. Remember that Newtons come from Kg • m / s² Instead of using all these units the scientific community created the term Joule to stand for all that.

So, given this girl pushing her bike, how much work is she doing? Which of these people is doing more work? Guy one. Guy two. Read the did you know and explain that if both mowers are the same mass They are doing the same work however, the boy is pushing in the direction he wants the mower to go. The tall man pushes with more downward force so not all the force is being exerted in th direction of the mower so he is exerting more force.

Splash the concept of heat:* Ask the students what temperature it is at their site? What does that mean? What does a thermometer actually measure? Heat always moves from warmer to cooler areas so where does it come from? Almost all heat can be tracked back to a nuclear reaction in our sun.

Guided Practice:* Students will take turns answering the questions for review on Page 208.

Independent Practice:* Students will read Lesson 1, What is Work, pages 206-207. Students will complete the worksheet, 08-01, What is Work?9

Check for Understanding:* Students will take the quiz, 08-01, What is Work?

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).

Alaska Content Standards Addressed in this lesson:

• SCI A-1 Students will understand models describing the nature of molecules, atoms, and sub-atomic particles and the relation of the models to the structure and behavior of matter (Structure of Matter);
• SCI A-2 Students will understand the physical, chemical, and nuclear changes and interactions that result in observable changes in the properties of matter (Changes and Interactions of Matter);
• SCI A-3 Students will understand models describing the composition, age, and size of our universe, galaxy, and solar system and understand that the universe is constantly moving and changing (Universe);
• SCI A-4 Students will understand observable natural events such as tides, weather, seasons, and moon phases in terms of the structure and motion of the earth (Earth);
• SCI A-5 Students will understand the strength and effects of forces of nature, including gravity and electromagnetic radiation (Forces of Nature);
• SCI A-6 Students will understand that forces of nature cause different types of motion and describe the relationship between these forces and motion (Motion);
• SCI A-7 Students will understand how the earth changes because of plate tectonics, earthquakes, volcanoes, erosion and deposition, and living things (Processes that Shape the Earth);
• SCI A-8 Students will understand the scientific principles and models that
  describe the nature of physical, chemical, and nuclear reactions;
  state that whenever energy is reduced in one place, it is increased somewhere else by the same amount; and
  state that whenever there is a transformation of energy, some energy is spent in ways that make it unavailable for use (Energy Transformations);
• SCI A-9 Students will understand the transfers and transformations of matter and energy that link living things and their physical

• SCI A-15 Students will use science to understand and describe the local environment (Local Knowledge); and:
• SCI A-16 Students will understand basic concepts about the theory of relativity, which changed the view of the universe by uniting matter and energy and by linking time with space (Relativity).
• SCI B- 1 Students will use the processes of science; these processes include observing, classifying, measuring, interpreting data, inferring, communicating, controlling variables, developing models and theories, hypothesizing, predicting, and experimenting;
• SCI B- 2. Students will design and conduct scientific investigations using appropriate instruments
• SCI B- 3. Students will understand that scientific inquiry often involves different ways of thinking, curiosity, and the exploration of multiple paths.
• SCI B - 4. understand that personal integrity, skepticism, openness to new ideas, creativity, collaborative effort, and logical reasoning are all aspects of scientific inquiry.
• SCI B - 5. employ ethical standards, including unbiased data collection and factual reporting of results; and
• SCI B - 6. employ strict adherence to safety procedures in conducting scientific investigations.
• SCI C- 1. Students will know how the words "fact," "observation," "concept," "principle," "law," and "theory" are generally used in the scientific community;
• SCI C- 2. Students will understand that scientific knowledge is validated by repeated specific experiments that conclude in similar results;
• SCI C- 3. Students will understand that society, culture, history, and environment affect the development of scientific knowledge;
• understand that sharing scientific discoveries is important to influencing individuals and society and in advancing scientific knowledge;
• SCI C- 4. Students will understand that some personal and societal beliefs accept non- scientific methods for validating knowledge;
• SCI C- 5 Students will understand that sharing scientific discoveries is important to influencing individuals and society and in advancing scientific knowledge;.
• SCI C- 6. Students will understand that scientific discovery is often a combination of an accidental happening and observation by a knowledgeable person with an open mind;
• SCI C- 7. Students will understand that major scientific breakthroughs may link large amounts of knowledge, build upon the contributions of many scientists, and cross different lines of study; and
• SCI C- 8. Students will understand that acceptance of a new idea depends upon sup- porting evidence and that new ideas that conflict with beliefs or common sense are often resisted.
• SCI D- 1. apply scientific knowledge and skills to understand issues and everyday events;
• SCI D-2. understand that scientific innovations may affect our economy, safety, environment, health, and society and that these effects may be long or short term, positive or negative, and expected or unexpected;
• SCI D- 4. evaluate the scientific and social merits of solutions to everyday problems;
• SCI D- 5. participate in reasoned discussions of public policy related to scientific innovations and proposed technological solutions to problems; and
• SCI D- 6. act upon reasoned decisions and evaluate the effectiveness of the action.