What Kind of Attraction Do You Have? Grade level(s): 2d and above Time to Teach: This is an excellent "rainy day" filler (40 minutes ) Area: Physical Science Strand: Static Electricity and Magnetism Material Required: (per small group) 1 hard plastic container with lid (such as a covered petri dish or margarine tub) Little, tiny bits of lots of "stuff" including, but not limited to ... (everything does not have to be in every dish) organic material, straws, penny, BB, lead shot, toothpick, aluminum foil, Styrofoam, string, copper wire, paper, staples, silver-colored wire, pin, some candy pieces (M&Ms), etc.), hard plastic spoon, piece of dry cleaning plastic, small bar magnet. Preparation Required: Having the cases (covered petri dishes or margarine tubs) already made and ready will greatly ease the trouble when the time comes. Providing material which are more susceptible to each of the camps (metals and very light plastics) would not hurt emphasizing of the concept. Concept: Magnetism is one of the fundamental forces of nature. Stationary electric charges produce electric fields. Objective: Students will prepare a table and predict the effects of a statically-charged item and a magnet on the objects in the container. Student will observe and record the results of both types of attraction. Background: We will soon be studying how the movement of electrons causes some materials to become charged, either positively or negatively. As with any good "rainy day" activity, it is self-contained and relatively undemanding if already set up. Holding the students to strict discipline during the prediction phase will increase the effectiveness of what they see during the observation/record phase. Set: I doubt if there is anyone in this class that has not worked with both magnets and seen commercials about static cling. Today, we are going to see whether these two events are related. Instruction: 1) Get yourself a covered dish, a plastic spoon, a piece of dry cleaning plastic, and a small magnet. 2) Make a list down the side of your paper of everything you see in your container. 3) Now make four columns. Call the first one "Predict Plastic" and the second one "Observed Plastic." Call the third one "Predict Magnet" and the fourth one "Observed Magnet. 4) In the first column, put a big "X" next to every item on your list that you think will be attracted to the plastic spoon. Put a "O" next to everything else. 5) In the third column, put a big "X" next to every item on your list that you think will be attracted to the magnet. Put a "O" next to everything else. 6) Now the moment of truth. First, "charge" the spoon with the dry cleaning plastic. Rub it firmly in one direction several times. With the lid still in place, quickly place the spoon over the objects in the case and observe any reaction. If any responds, place an "X" next to it in the second column. 7) Repeat the procedure with the plastic and the spoon as often as necessary. Observe and record. 8) Again, with the lid still in place, place the magnet over the objects in the case and observe any reaction. If any responds, place an "X" next to it in the fourth column. 9) Compare your predictions and the actual results. Practice: Have the students continue the experiment for several trials, eventually the lid of the container will also begin to attract the same items the spoon did, but not the ones the magnet did. Ask the students to write down their ideas for the reasons behind this phenomenon. Closure: Questions/Answers (Assessment): Make your own summary list where everyone can see it. Look for student responses that might be like, "But, I thought that all ... " Q: Were any of the metals attracted to the spoon? A: Only the very light weight ones such as aluminum foil. Q: Were all the metals attracted to the magnet? A: Some were and some weren't. (Be sure that there is some aluminum foil in the containers.) Q: Where did you find differences between your magnetic predictions and what you actually observed? Do you have any guesses about what caused the differences? A:. Answers will vary a bit. Q: Where did you find differences between your "spoon" predictions and what you actually observed? Do you have any guesses about what caused the differences? A: Answers are going to vary a lot. Try to save the explanation details for the lesson devoted to static electricity and the attraction that results on even uncharged objects. BUT IF YOU CANNOT: Q: Why did the objects that were attracted to the spoon begin to "stick" to the lid of the container? A: You can give them at least a "taste" of the principle and effect behind those devilishly mobile electrons. Possible Follow-up Activities (Extension): Almost without saying, this activity will need to be followed eventually by lessons in both static electricity and magnetism. However, the activity does stand on its own nicely as a simple predict and observe lesson without all of the other "stuff." Possible Modifications: This lesson can be combined with the opening phases of an electricity block, but make sure that you have an extended period of time available. Static electric attraction is least one lesson on its own without this one. Therefore, make sure that you are ready for the banquet before you decide to take that first bite. Adapted by: Buddy Farrar SCI 442, MTSU, Spring 1996