Author: Diane Zak
Source: Adapted from Science NetLinks grade 3-5 Magnets; Student Sheet - Magnetic Pick-ups
This lesson uses a "Magnetic Discovery Bottle" to teach students:
What should students know as a result of this lesson?
What should the students be able to do as a result of this lesson?
1 clean 1-liter water bottle with a magnetic wand attached (for each center or group of students).
The wands may be ordered from Educational Innovations: www.teachersource.com The order number is #M-510 currently (2005-2006) $1.50 each. Tie one wand to each bottle's neck with a string or piece of yarn. (The magnetic wands work better and are easier to use than other types of magnets.)
Collections of the following items:
Put 4-5 items from the suggestions above in each bottle. To keep students from removing the cap and taking out the items, glue the cap back on the bottle. Then tie on the magnet. For ease of distribution and data collection, consider numbering the bottles.
Before proceeding, by your questions and their responses, make sure that students understand PREDICTING: Knowledge from previous experience is used to make a prediction (what you think will happen), that can be tested.
Two balls (one large: volley ball, one small: golf ball) or (one heavy: soft ball, one light: tennis ball)...Which ball will hit the floor first when both are dropped from the same height and dropped at the same time?
Allow students to observe, touch, and lift the balls before dropping them.
Test your predictions: Drop both balls at the same time from the same height; observe (Both balls will hit the floor at the same time.)
*It may be necessary to drop the balls a few times to make sure both balls hit the floor at the same time.
Tell the students that when they made a guess about what would happen to the balls, they were making a prediction. Scientists make predictions about what they think will happen when they test something.
Before proceeding, be sure that students understand the posed problem: Tell the students that today they will be making predictions about magnets. They should use what they already know to make their predictions.
Assessment: Monitor students' answers to your questions to be sure everyone understands the goals of the lesson. Use the students' input to make a class chart or poster illustrating the steps involved in making predictions. (1. make careful observations, using their five senses 2. past experiences and prior knowledge 3. guess what will happen next)
*If the students need help with the answers, prompt them – What was the first thing they did with the balls? (Looked at them, touched them, lifted them). What was the second thing they did before the balls were dropped? (Made a prediction/guess about which ball would hit the floor first). What was the last thing they did? (Observed the balls being dropped to find out if their predictions/guesses were correct).
* Older students may be in groups of 3 or 4. Very young children work better individually.
Assessment: Monitor students' work to check that they are carrying out procedures carefully, making observations, and recording data accurately.
Redirect their attention to the task, as needed.
Make sure that students are employing safe practices as they conduct the activity.
Check to see that each member of the group is participating.
Answer students' questions regarding procedures.
Note: Be aware that explanations of the phenomena will be discussed in the next part of the lesson, so do not give answers to questions aimed at explaining "why" something is happening or not happening.
Students report their findings.
Assessment: Listen to students' accounts of their findings to judge if their reports are supported by the findings that you observed as experiments were being conducted. Ascertain students' knowledge of magnets by having the students make a poster illustrating and labeling what they learned about magnets, their properties, and objects that are attracted to magnets.
Older students could make a cartoon, with a minimum of 5 or 6 sections, explaining the kinds of things that are attracted to magnets, properties of magnets, and several uses of magnets.
Younger students could draw a picture depicting things that are attracted to magnets, properties of magnets, and several uses of magnets.
A fun demonstration: Iron is a mineral the human body needs to carry oxygen in the blood. With insufficient iron, a person will feel very tired much of the time (anemia). We get this iron from the foods we eat. Packaged foods have a food label listing the ingredients. The cereal "Total" contains 100% of the iron a person needs in one day.
Assessment: Take a survey of magnets in their home. Make a chart with two columns. The first column should contain the name of the appliance, object that uses a magnet, or is a magnet. The other column should contain information about how the magnet is used. Example: Refrigerator door ……. Uses magnets to keep the door closed; Decorative flower magnet ….. Used to attach notes to the refrigerator; calendar magnet ….. Used to keep track of the date.
Discuss the safety rules for magnets, pointing out the items in the classroom, which should be avoided. (Depending on the age of the students, it would be wise to visually mark these with a warning sign.) See "Safety"
PREDICTING: What you think will happen
A hypothesis is an educated guess, based on previous experiences. Correct or incorrect predictions, in science, do not matter. What does matter is that the prediction leads us to a test that can lead us to the truth. Making careful observations provides us with information. We can use this information to make predictions about possible answers to our questions. Our answers are based on our observations and previous experiences. The prediction must be one that can be tested. For example: See Procedure (Learning Cycle)
Materials that are attracted to a magnet become temporarily magnetic themselves. Examples students may be familiar with include paper clips, scissors, screw driver. Iron (or iron alloys), like steel, are the most common objects that are magnetic. Three other metals that are magnetic, but are not commonly found, are nickel, cobalt, and barium ferrite. These four metals are called ferromagnetic metals. A U.S. nickel does not have a high enough nickel content to be magnetic, but a Canadian nickel does.
Many appliances such as computers, radios, telephones, TVs, and speakers use magnets as part of their internal make-up. All electric motors consist of a rotating electrical conductor that sits between the poles of a stationary magnet. See "Applications"
Caution needs to be exercised when using magnets since placing magnets near computers and computer discs, television sets, wind-up watches, cassette tapes, answering machines, VCR's, microwave ovens, radios, tape recorders, telephones, or credit cards can damage these items. If magnetic marbles are used be aware that these marbles look a lot like bubble gum – a possible safety issue
Remind students to use science materials for the correct purpose; no horseplay in the lab; be careful not to put objects in your mouth; do not share materials with students in another group.
In homes: magnets are used in advertising and decorations such as refrigerator magnets. They are useful as fasteners and latches. They are necessary parts of the operation of refrigerators, vacuum cleaners, washing machines, compact disc players, blenders, hedge trimmers, drills, audiotapes, videotape players, and speakers, toy trains, toy cars, and robots…in anything that moves or rotates, since all electric motors consist of a rotating electrical conductor that sits between the poles of a stationary magnet.
Magnets in telephones, radios, and TV sets help change electrical impulses into sounds.
Industry: Cranes, fax machines, photocopiers, printing presses, and computers. Huge magnets move iron and steel scrap.
Transportation: Trains, trolleys, subways, monorails, cable cars, escalators, elevators, moving sidewalks, windshield wipers, electric windows and doors, door locks and other devices in automobiles, buses, and airplanes. Electromagnets produce radio waves in radar systems which is important as a navigation aid for ships and airplanes.
Medicine: MRI used for diagnosing diseases.
See Learning Cycle, Exploration, and Elaboration Assessment, Student worksheet
Grouping Suggestions: Older students can be placed in groups of 3-4 students with varied abilities. Assign each student in the group with a job. Relate jobs to real-world positions such as managers with job descriptions. See worksheets: Managers' job title with job descriptions. The Managers' job descriptions can be printed out on colored paper, a different color for each job. Provide each group with a set of these cards. With very young children, you may prefer to have the students work alone.
Pacing/Suggested Time: This activity will take 2-4 class periods.