Electromagnetics for 8 th grade

1. Activity Under Development We value your input! Electromagneticsfor 8th grade

2. Activity Guide • Challenge: Discuss (5-10 minutes) • Generate Ideas and Multiple Perspectives (instructor choice) • Research and Revise (and Test Your Mettle) • Activity 1: Review the relationship between electricity and magnets (5-10 minutes) • Activity 2: Copper coil motor (10 minutes) – this can be conducted as a demonstration or each group can construct a copper coil motor • Activity 3: Create a Current Detector (15-20 minutes) • Activity 4: Create an Electromagnet (15-20 minutes) • Activity 5: Complete Data Chart (10-15 minutes) • Go Public: Revisit challenge (instructor choice)

3. Teacher Tips • The magnetic motor can be a demonstration/review or a hands-on activity for your students. • You may need to use the needle nose pliers to straighten the ends of the copper coils used in the magnet motor. BE CAREFUL not to bend the coil. • The current detector shows dramatic response when testing the battery and much less dramatic response with the electromagnet. It does show a response, though! • These experiments show the relationship between electricity and magnets. • A magnet that is moved past a copper coil causes the electrons to move, moving electrons create electricity. • This activity is designed for 6 groups of 4 students each. • Each group of students will do the same activities. • You will prepare a bin of materials for each of the 6 groups.

4. Teacher Prep • Assemble materials from next page • Set up 6 bins of the same materials for 3-4 students at each of 6 tables • 4 D-cell batteries • 4 D-cell battery holders • 2 pieces of 3 meter copper wire with insulation stripped off ends (they are coiled on cardboard) • 1 piece of ½” diameter PVC tube • 2 jumper cables • 1 compass • 1 roll clear tape • 1 bar magnet • 1 12 cm iron nail • 1 plastic bowl • 1 box of 100 paper clips • 1 Electromagnetic chart • 2 safety pins • 1 copper wire coil • 1 metric ruler • Set up 6 stations, 1 at each table.

5. Materials • 24 D-cell batteries • 24 D-cell battery holders • 12, 3-meter piece of 18-24 gauge insulated wire with ends stripped off • 12 jumper cables • 6 compasses • 6 rolls clear tape • 6 bar magnets-plain • 6 bar magnets with North and South Poles marked • 6 12 cm iron nail • 6 plastic soup bowls • 6 boxes of 100 paper clips • 6 copies of Electromagnet Data Chart – stored in mechanical room filing drawer on bottom left • 6 PVC pipes ½-inch diameter x 4-inches long • 6 copper coils (with ends stripped) • 12 large safety pins • 6 pens/pencils • 6 metric rulers

6. Location of All Materials Drawer 4a1: • 4 boxes labeled bar magnets • 9 ½” diameter PVC tubes • 10 6” iron nails • 8 bags of 100 paper clips • 28 mechanical pencils • 9 compasses Drawer 4a2: • 12 rolls clear tape • 7 ceramic bar magnets • 16 jumper cables Drawer 4a3: • 20 D cell batteries • 6 sets of insulated copper wire (2 4-meter lengths rolled on cardboard) • 8 rulers • 36 D-cell batteries • 1 plastic box containing 8 copper coils, 16 safety pins, 8 rubber bands, 1 pair needle nose pliers Drawer 4a4: • 8 plastic bowls

7. Worksheet

8. Challenge • The president of a local office supply company, STEMco, has asked your class to design and build an executive desk toy. • The toy must be capable of some type of motion OR light up, but cannot contain batteries or be connected to an electric outlet. • The president’s son owns a magnet factory, so the toy MUST contain at least one magnet.

9. Guiding Question • How are electricity and magnetism related? • How can we detect electric current with a magnet, compass, and battery? • How can we create an electromagnet? • What can you do with a simple motor? • Review – • What is electricity? • What is an electromagnet?

10. Activity 1: How are electricity and magnets related? (5-10 minutes) • A magnet can induce an electric current when moved through a coil of copper wire. • A magnet that is moved past a copper coil causes the electrons to move. • Electricity is the flow (movement) of electrons. • A magnet can also reverse the flow of electrons (electricity) in a copper wire.

11. Activity 2: Create Copper Coil Motor(10 minutes) • Materials needed: • 1 D cell battery • 1 coil of copper wire • 1 bar magnet • 2 safety pins • 1 rubber band The teacher can conduct this part of the activity as a demonstration for review or engagement!

12. Attach doubled rubber band to battery.

13. At each end of battery, insert one safety pin in between rubber band and battery. Make sure both safety pins are level at the top.

14. Put a magnet under the battery - in line with the long axis of the battery.

15. Insert copper coil in the small loops at the top of each safety pin. You may need to use the needle nose pliers to straighten the ends of the copper coil. BE CAREFUL not to bend the coil.

16. Very lightly spin the coil. What happened?Now reverse the magnet. What happened?

17. Take Apart Copper Coil Motor • Take apart the coil motor. • Remove magnet from battery. • Remove copper coil from safety pins. • Remove safety pins • Remove rubber band. • Return materials to your bin.

18. Activity 3: Creating a Current Detector(15-20 minutes) Materials for each group of 4 students: • 2 jumper cables • 2 pieces 18 gauge wire 3 meters long (with ends stripped) • Small compass • D-cell battery • D-cell battery holder • Strong magnet • 4 inch piece of ½-inch diameter PVC pipe • Clear tape

19. Wrap 3-m wire around compass • Wrap loops tightly around middle of compass: • Leave 40 cm at the end. • Wrap from North to South. The wire must stay at the middle of the compass • TIP: you may want to tape the wire on the compass to hold it in place as you wrap.

20. Placed D-cell battery in battery holder.

21. Line up the compass on your desk • Make sure North points North and lines up with the wire loops. • This is your current detector!

22. Connect one end of wire to the D-cell • Connect the compass to the D-cell battery using jumper cable. One end of the jumper cable on the compass wire, one end on the battery.

23. Touch other end of wire to D-cell • Connect a 2nd jumper cable to the battery terminal. • Touch the free alligator clip to the bare end of the wire. • Observe what happens and record your observations in your Electromagnet chart. • Disconnect the jumper cables from the battery and compass.

24. Wrap 3-m wire around PVC tube • Leave at least 50 cm of wire at each end. • Wrap tightly but DO NOT overlap the wires. • TIP: you may need tape to hold the wire in place as you wrap.

25. Connect one wire on current detector • Use a jumper cable to connect one wire on the current detector to one wire on the PVC tube. • Use a second jumper cable to connect the other wire on the current detector to the free wire on the PVC tube. It is very important that the cardboard tube is as far away from the compass as is possible!!!

26. SLOWLY insert a magnet labeled with North and South into the PVC tube and pull out. Insert and pull out. • Observe and record what happens to the compass needle. • The compass must be FLAT to work. You may need to hold it in place. • Note: South is inserted into the tube in the image below.

27. Predict …. • What will happen to the compass needle if you reverse the magnet before you insert it into the tube, North first? • Now test your prediction. Remember the compass must be FLAT to work. • Note: North is inserted into the tube • Disconnect all wires and straighten wire that was wrapped around PVC. Wrap it around cardboard and return materials to your bin.

28. Conclusions – for your worksheet • Describe what happened to the compass when current ran through the wire. • Describe what happened when you reversed the position of the bar magnet in the tube. • In what way is the compass needle’s movement evidence of a current in the wire? • What do you think produced a current in the wire?

29. Activity 4 - Create an Electromagnet(15-20 minutes) Materials per group of 4 students: • 4 D-cell batteries • 4 D-cell battery holders • Large iron nail (16 cm) • 100 metal paper clips in a plastic bag • Small plastic container • 2 jumper cables • 3 meters of 24 gauge copper wire with ends stripped off • Electromagnet Chart

30. Wrap wire around nail • Leave approximately 25 centimeters of wire free at each end. • Wrap the wire around the nail tightly, making your coils as close together as possible. Do NOT overlap the wire!!! • Stop at the end of the nail. (You may have more than 25 centimeters of wire left at that end.)

31. Insert batteries in battery holders • Make sure – end of battery is at – end of battery holder.

32. Connect wire to battery • Use a jumper cable to attach one end of the wire to one end of the battery. • Connect another jumper cable to the free end of the battery and the free end of the wire. • This is an electromagnet.

33. Test your electromagnet • Place one end of the electromagnet in a bowl full of paper clips. • Count the number of paper clips and record in your Electromagnet Data Chart. • Repeat this test 2 more times. • Record in Electromagnet Data Chart. Calculate average # of paper clips picked up. • Disconnect one end jumper cable from the battery.

34. Add 2nd battery • Clip another battery in series onto your electromagnet. • Re-test it and record the number of paper clips you can pick up. • Repeat this test for a total of 3 trials. • Record in Electromagnet Data Chart. Calculate average # of paper clips picked up. • Disconnect one jumper cable from battery.

35. Add 3rd battery • Clip a third battery in series onto your electromagnet. • Re-test it and record the number of paper clips you can pick up. • Repeat two more times for a total of 3 trials. • Record in Electromagnet Data Chart. Calculate average # of paper clips picked up. • Disconnect one jumper cable from battery.

36. Add 4th battery • Clip a fourth battery in series onto your electromagnet. • Re-test it and record the number of paper clips you can pick up. • Repeat two more times for a total of 3 trials. • Record in Electromagnet Data Chart. Calculate average # of paper clips picked up. • Disconnect one jumper cable from battery.

37. Activity 5: Complete data chart(10-15 minutes) • Calculate the average number of paper clips picked up for each total battery voltage and record in Electromagnets Data Chart. • Graph your results. • What happened to the electromagnets strength when you added more volts?

38. Go Public: Revisit the Challenge • The president of a local office supply company, STEMco, has asked your class to design and build an executive desk toy. • The toy must be capable of some type of motion OR light up, but cannot contain batteries or be connected to an electric outlet. • The president’s son owns a magnet factory, so the toy MUST contain at least one magnet.

39. Vocabulary • Electromagnet - An arrangement of wire wrapped around a core producing a temporary magnet • Electricity – the low of electrons • Induce – cause to happen • Magnet – object that attracts certain metals (especially those containing iron) • Maglev – magnetic levitating system. • A transportation device that relies on electromagnets to propel it. • Repulsion and attraction work to push and pull the train along.