Name: Date: D. Thomassen 2007 Machines by Lillian Duggan answer key Colorado Model Content Standard #2: Physical Science: Students know and understand common properties, forms, and changes in matter and energy. Directions: After reading this text, complete the following organizer parts. Remember to reread any part of the text that confused you. You are a great reader. Part I: Vocabulary Preinstruction: Vocabulary Word: compound machine effort force fulcrum load machine simple machine work Definition: a machine that contains one or more simple machines the force applied to a lever to lift a load the supporting part of a lever an object s weight that applies a force on a lever any device that helps people do work a machine made up of one or two parts using force to move an object a certain distance 1. visual ( Follow along with your eyes as I spell it out loud ) 2. auditory (Hear the parts /p/ /ea/ /ch/) 3. kinesthetic (trace with eyes, write it on the table, hand, etc.) 4. phonics (break the word apart) discuss prefixes, suffixes, roots, compounds, phonograms, double vowels, silent e. 5. meaning (give the definition and/or an example) 6. give an example. I will be working with this group, meanwhile, this group will be at computers. -------------------------------------------------------------------------------------------------------------------
Part II: Comprehension 1. Write down the equation for work. Next, explain in your own words what this equation means: Work=Force X Distance. This equation means that to do work you have to apply force and move something a certain distance. 2. What is one difference between simple and compound machines? Simple machines are made up of one or two parts and compound machines are made up of many parts. 3. Machines help us do work by decreasing the weight of certain objects. changing the distance over which the force is applied. changing the components of the object. increasing the weight of certain objects. 4. Complete the following information grid regarding the three types of levers: Lever Type: First-Class Lever Second-Class Lever Third-Class Lever: Where is the fulcrum, effort force, and load in this type of lever? The fulcrum is between the effort force and the load. The fulcrum is at one end and the effort force is at one end. The load is in the middle. The fulcrum is at one end and the load is at one end. The effort force is in the middle. What is an example of this type of lever? pliers, teeter totter nutcracker, wheelbarrow crab claw
Use this key to answer questions 5-7: Effort Force Load Fulcrum 5. Consider the diagram below. What type of lever is represented here? First-class lever Second-class lever Third-class lever 6. Consider the diagram below. What type of lever is represented here? First-class lever Second-class lever Third-class lever
7. Consider the diagram below. What type of lever is represented here? First-class lever Second-class lever Third-class lever 8. A pulley helps to reduce the amount of work by changing the distance you have to lift the load. making the load lighter. changing the direction of the force. making the load travel a shorter distance. 9. What was the author s purpose in writing this book? The author wanted to persuade the reader to study the three different types of levers. The author wanted to inform the reader about different machines and how they help us to do work. They author wanted to inform the reader about how machines are becoming unnecessary in today s world. The author wanted to entertain the reader with stories about compound machines like sail boats.
Part III: Compare and Contrast: Study the following list of machines that help us to do work. Next, place the machines in the correct lever-class category: ice tongs, teeter-totter, fishing pole, wheel barrow, crowbar, scissors, pliers, bottle opener, nut cracker, tweezers, and shovels Study the diagrams above if you need assistance. Remember to think about where the force is applied, where the load is located, and the position of the fulcrum. You are an awesome physicist! Class 1 Levers: Class 2 Levers: Class 3 Levers: teeter totter crowbar scissors pliers nutcracker wheelbarrow bottle opener fishing pole tweezers ice tongs shovels
Part IV: Fluency Practice: Follow the four-step fluency practice steps: 1. Read the following excerpt from the text to your teacher. You must focus on pronouncing each word correctly. Take your time and do a great job. Your teacher will then discuss any words that may have been difficult for you. Record your time in the space provided. 2. Read the following excerpt from the text to yourself. Record your second time in the space provided. Ask yourself: Do I understand what happened in the text? 3. Read the following excerpt from the text to a classmate. Record your third time in the space provided. Ask yourself: Is my fluency speed improving? 4. Read the following excerpt from the text to a parent or sibling. Have them sign in the space provided. This will let your teacher know that you completed the fourth step of your fluency practice. Fluency Goal: Your fluency goal for this excerpt is to cut your time in half from your first reading to your fourth reading. If you do not complete your goal, you need to continue reading this excerpt until you accomplish that goal. When you have reached your goal, write down the main idea (one sentence) of your excerpt on the line provided. You will read this excerpt to your teacher one final time. Machines do not change the amount of work that is done. Remember, work is equal to force multiplied by distance. Machines make work easier by changing the distance over which the force is applied. Spreading the force required over a longer distance decreases the amount of force you need to apply at one time. A car jack is a machine that helps you lift a car. Cars are too heavy for people to lift. A jack decreases the force that s needed to lift such a heavy object by applying force over a longer distance. A screw-top lid works the same way. Without the screw top, you would have to slam down the lid hard to cover a jar. With a screw top you must move the lid a longer distance, but you use less force to close the jar. 139 words First Read: Second Read: Third Read: Fourth Read: Parent Signature: Main Idea: