Science SCI.IV.1.6 Grade: 7 Strand IV: Using Scientific Knowledge in Physical Science Standard 1: Matter and Energy ­ All students will explain how electricity (and Magnetism) interact with matter. Benchmark 6: Investigate electrical devices and explain how they work, using instructions and appropriate precautions. Constructing and Reflecting: SCI.I.1.1 ­ Generate scientific questions about the world based on observation.
· Construct questions for each of the investigations suggested below to guide the design of the investigation. SCI.I.1.2 ­ Design and conduct scientific investigations.
· Experiment with batteries, bulbs, and wires to make and test electric circuits.
· Experiment with batteries, wires, and a nail to make and test an electromagnet. SCI.I.1.3 ­ Use tools and equipment appropriate to scientific investigations. SCI.I.1.6 ­ Write and follow procedures in the form of step­by­step instructions, formulas, flow diagrams, and sketches. SCI.II.1.3 ­ Show how common themes of science, mathematics, and technology apply in real­world contexts. SCI.II.1.4 ­ Describe the advantages and risks of new technologies. Vocabulary / Key Concepts Context Flow of electricity for energy or information transfer. Situations requiring assembly, use, or repair of electricity:
· electrical toys
· radios
· simple appliances (replacing batteries and bulbs) Safety precautions for using electrical appliances; grounding. Documentation for toys and appliances; wiring diagrams and written instructions. See IV.2.MS.3 Transformations of energy Connecting electrical appliances:
· stereo systems
· TV’s and videocassette recorders
· computers and computer components.
Knowledge and Skills Students will investigate electrical devices and explain how they work by following the flow of energy through a device. Students will determine if the circuit is complete to make the appliance work by reading a flow diagram, which is often included in an instruction manual E.g.: A VCR connected by a cable to a TV, a printer connected by a cable to a computer. Safety precautions: Surge Protectors work as a circuit breaker to protect electrical appliances from an overload of current reaching the appliance. Resources Coloma Resources: Electricity and Magnetism Book – Chapter 2 Build a Flashlight pg. 36­37 in book listed above. Other Resources:
· SMILE – IL Institute of Tech – Electricity and Magnetism links – 35+ single concept lessons vetted and posted by teachers. Excellent!
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Grounding is an example of a safety precaution. Grounding is the connecting of a charged object to the ground by way of a conductor e.g. lightning rod to dissipate extra charge. ·
Caution: Taking apart large appliances is dangerous! Residual charges in capacitors can injure students. Teachers’ Domain – Electricity and Magnetism – video clips, interactives, images and documents. Awesome!! (1 st link­ free sign­up, 2 nd link info)
ThinkQuest – Electronics: an Online Guide for Beginners ­ Outstanding site!
· SCoPE ­ Unit Plan for Energy ­ Moving It and Using It
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Michigan Teacher Network Resources
· The Blobz Guide to Electrical Circuits – fun, interactive, self­assessing and highly informative – Excellent site!
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JCISD – Inquiry Activities on Electricity – EXCELLENT resource for teachers!!
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Bill Nye: Gravity, Friction, Magnetism
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Science Explosion
Instruction Benchmark Question: How do humans use electricity safely? Focus Question: How do electrical devices work and how are they safely used? Assessment Coloma Assessment Safety Poster Topic: “What Not To Do” Optional Assessment Have students work in groups of 2 or 4. Give each group a small, broken electrical device. (e.g. flashlight, battery­operated toy) The students will explain at least 4 reasons why the device might not be working, and at least two safety precautions, which should be taken while fixing the appliance. Compare characteristics of several working appliances. Include on/off switches, wires, complete circuits, etc. Have students take apart flashlights, reassemble to work, and diagram the internal mechanism showing current flow. Have students bring in small broken appliances from home. In small groups, take appliances apart and Have students take the above scenario home to have students hypothesize why the appliance is parents and explain why an electrical device not working. does not work. Further suggestion: have an appliance repair person come to class to discuss students hypothesis as to why the appliances are not working. NOTE: Remind students that when working with an electrical appliance to disconnect it from the power source. Teacher should instruct students on proper electrical safety procedures. (Give students rubric before activity.) Scoring Rubric Criteria: Accuracy of explanation: Apprentice ­ Explains fewer than two valid reasons why appliance does not work. Basic ­ Explains two to three valid reasons why appliance does not work. Meets ­ Explains four valid reasons why appliance does not work. Exceeds ­ Discusses five or more valid reasons why appliance does not work. Criteria: Appropriateness of safety precautions: Apprentice ­ Describes no safety precautions. Basic ­ Describes one safety precaution. Meets ­ Describes two safety precautions. Exceeds ­ Describes three or more safety precautions. Poster Rubric 5 – Originality 10 – Accuracy of information 5 – Neatness 10 – Essay describing in words what poster is saying in picture 30 Points Total
Teacher Notes: “Electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced.” (NSES) Electrical charges flow from one side of a source of electrical energy (battery, generator, wall plug) through the circuit devices (lights, bells, motors, etc.) and back to the source. The circuit must be complete in order to work; switches can open a circuit, making it incomplete and therefore not allowing current to flow. The battery or other source provides energy to the electrical current, which is transformed in the circuit devices to other forms of energy (light, heat, sound, motion, etc.) Energy is neither created nor destroyed in this process; it only transforms from one form to another.
· Electricity in a coiled wire produces a magnetic field. The force that magnets exert on certain metals and each other is an invisible force that acts “at a distance” without coming into contact with the object it moves. Electric charges can also exert non­contact forces, following the same rules as magnets (like charges repel, unlike charges attract).
· Gravity is also a non­contact force. However, it is only an attractive force. Non­contact forces weaken quickly as the distance between the objects increases. (JCISD) Focus Questions
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How does a current flow in circuits?
How do humans use electricity safely?
What are the non­contact forces affected by magnets, static electricity and gravity?
What is the relationship between magnetic forces and electric currents?
What is energy and how does it transfer from one substance to another in everyday situations? Notes The middle school electricity benchmark does not require students to differentiate between parallel and series circuits. The corresponding high school benchmark addresses that. (JCISD)
Name Date SCIENCE INTEGRATION ACTIVITY Force is a push or pull on an object. Earth's magnetic force affects our lives in many ways. Even though we cannot see this force, we can see some of its effects. The force is behind the northern and southern lights, and it makes a compass usable. In magnetic metals (iron, nickel, cobalt) there are tiny sections called domains that are like miniature magnets. Usually the domains are not lined up, so they pull in different directions. When the domains are lined up, the metal becomes a magnet. Magnets can form naturally. Called lodestones or magnetite, they can be used as natural compasses. Getting Started How can we see an invisible force around a bar magnet? One way is by sprinkling iron filings on a piece of paper placed over a bar magnet. Studying a bar magnet's magnetic field will help you in comprehending Earth's magnetic field. Thinking Critically Draw what you think the force field will look like around a bar magnet. TRY IT! You will need:
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bar magnet
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iron filings (in shaker)
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paper
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self­sealing plastic sandwich bags
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horseshoe magnet (optional)
Class 13 1. Place a bar magnet inside a plastic bag and seal the bag. Set an 8.5 inch x 11 inch sheet of paper over a bar magnet. 2. Carefully sprinkle a small amount of iron filings evenly on a piece of paper. Be careful not to get any directly on the magnet. Draw the force field in the box provided. 3. Lift the paper off the magnet and carefully pour the filings back into the container. 4. Using two bar magnets, put two north ends close together (5­10 cm). Draw the force field. 5. Put a north and south close together (5­10 cm). Draw the force field. 6. Repeat the procedure if you have a horseshoe magnet available. Observations Summing Up/Sharing Results The strength of the magnetic field is greatest in the are(is where the filings are most attracted. What areas of your bar magnet have the greatest magnetic strength? If a bar magnet is similar to Earth's magnetic field, where would you expect Earth's magnetic force to have the greatest strength? What did you learn about like and opposite poles? Going Further Sometimes people observe an eerie light in the night sky called the northern lights or aurora borealis. In the southern hemisphere it is called the aurora australis. Research the cause of the northern lights and what it has to do with Earth's magnetic field.