Light and Electricity Activities: Division I

Activity 1: Who needs a compass? (1-2 class periods)

Integration Notes:
This activity helps students understand how easy it is to lose track of direction when familiar landmarks are removed. It makes evident the need for the Phase 1 challenge to build a compass. This experience will also be a good reference point for the Phase 2 orienteering challenge.

Also see the Phase 1 implementation and integration notes for Energy and the Environment.

Learner Outcome:
Students will appreciate the need for a compass when familiar landmarks are not discernible.

Materials:
For the entire group:

• large, enclosed space (e.g. a gym)
• picture of the ocean with no landmarks visible on the horizon
• picture of a dense blizzard
• picture of a thick forest picture of a snow-covered Arctic plain

• blindfold
• a commercial compass

Introduction:
In this activity, students are blindfolded and challenged to make their way across the gym (while they role-play carrying a heavy pack and trudging through deep snow). As various distractions present themselves, they gradually change their course and end up at a different wall than the one they intended.

Activity Instructions:
1. At one end of the gym (or other enclosed space), blindfold half of the students. Tell them that they are bundled up in heavy gear, that it is cold outside, and that their goal is to walk to the opposite wall of the gym with no coaching from the other students.

Note: there is added challenge if the students start at different walls so that they can't use the footsteps of their friends as a reference point to their location in the gym.

2. Tell the students that they will receive instructions from you at various points during their walk, but that they should not take their blindfolds off until they arrive at the opposite wall (depending on where they start), at which point they may quietly observe the progress of their classmates.

3. Instruct the other half of the class to sit very quietly at various points around the perimeter of the gym and to observe the progress of the climbers (any noise will act as a reference point for the blind travelers).

4. After the blindfolded group starts, call out various instructions from different points in the gym (again, to remove sound as a reference point). Sample nstructions:

• You dropped your water bottle! Stop to pick it up.
• You hear a loud noise behind you! Turn around to check it out.
• A bunch of snow has accumulated on your right boot. Bang it against your left boot to make walking easier.
• You're very tired. Sit down to rest.
• Tie your boot. Trip and fall. Get up, brush yourself off, and continue.

Include activities that require them to change their orientation. Each time they do one of these things, they will likely unknowingly alter their direction. Continue calling out distractions until a large portion of the group has changed their direction of travel.

5. Once all of the students have reached a wall, ask students to remove their blindfolds and do a quick tally of the number of students who made it to the correct wall (the opposite of where they stated).

6. Reconvene the group to discuss what happened

• At what points did the travelers alter their directions?
• Did it feel like you changed direction?
• Why did the travelers veer off of the planned path?
• What clues to direction might exist on a mountain that do not exist in the gym (e.g. wind direction, slope of the land)? What might make it even more difficult (being cold and / or frightened the possibility of falling off of a cliff if you veer right or left)?

7. Switch groups and repeat the activity.

8. Return to the classroom. Show students pictures of the ocean, the forest, the blizzard, and the Arctic plain. Ask them if they think it would be any easier to find their way in these environments than it was blindfolded.

Some of the students may still feel that having their sense of sight would make a difference in these situations, so encourage them to voice and debate their ideas. If they still have difficulty making this connection, have them considering moving in a completely dark room without a blindfold: Why can't we tell direction in the dark? This should help to bridge their understanding of being blindfolded to the situations in the pictures.

Relate this experience to the Everest expedition and the types of weather problems they might face as they are climbing. For electronic resources and ideas for online interaction with the Everest team, review the Implementation and Integration Notes for Energy and the Environment, Phase 1 - Division I. Also browse through the whole site for pictures and information about Mount Everest and the Nepalese Sherpas who guide the climbers. Resources will come online throughout the phase.

9. Distribute compasses to the students. Allow them a few minutes to investigate them, and then discuss how they could help a person find their way if their sense of direction were impaired by surroundings that look the same in all directions.

10. EXTENSION: If time permits, you may wish to repeat the blindfold activity, only this time, give each blindfolded person a sighted partner to act as a "compass" who is allowed to turn them in the direction of the wall every time the blindfolded partner asks for help.

This is akin to looking at the compass. If the person who is blindfolded doesn't ask very often, he or she could still end up far to the right or left of the intended destination, but they should eventually arrive at the appropriate wall.

The reasons for, and the potential implications of, the left/right deviation would also make an interesting discussion. If you keep turning back to the proper direction, why do you end up so far to the side? Would this matter if you were climbing a mountain in a blizzard? Why or why not?

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Activity 2: Discovering the "law of magnets" (1 class period)

Integration Notes:
This activity is best presented after "Who Needs a Compass?" It will help students design their own compasses and is part of a series of activities designed to prepare students for the orienteering challenge presented in Phase 2.

Also see the Phase 1 implementation and integration notes for Energy and the Environment for suggestions of electronic resources and ideas for on-line interaction with the Everest team.

Learner Outcomes:
Students will:

• Develop an understanding that like poles of a magnet attract and that unlike poles repel.
• Understand how we "know" which end of a magnet is north and which is south.

• 3 unmarked bar magnets
• 2 cm of masking tape (to mark 1 end of each magnet)

2. If some students already know that like poles repel and unlike poles attract, challenge them to figure out how they came to know this. They will likely refer to the attraction of like poles on marked magnets, but ask them how the person painting them knew which end was which.

3. Distribute 3 unmarked bar magnets to each pair of students, and let them explore the properties of the magnets and the interactions between them. (10-15 minutes)

Note: Some students will likely speak about the poles of the magnets as "liking" or "disliking" each other. This may help them to articulate their understandings. At the end of the class, it may be worthwhile to discuss whether they truly have feelings or whether something else is causing the attraction and repulsion.

4. Have each group share their ideas regarding why the magnets behave the way they do. Introduce the terms "attract" and "repel" to help the students describe their experiences of the magnets "sticking together" and "pushing apart."

Ask them when the magnets stick and when they repel. Is there a "sticky side" and a "pushy side"? Allow them to test this idea if they haven't already.

5. Of course, both poles can attract and both can repel. So how would anybody know which end is north and which is south? As the magnets are unmarked, it is difficult to tell. Discuss possible solutions to the problem. (10-15 minutes)

6. After the students have formulated more elaborate ideas, allow them to investigate further with the magnets. Suggest that they mark ends of each magnet with a small piece of tape as they continue their work with the magnets. As they are working, encourage them to articulate how the poles of the magnets differ.

If necessary, ask questions to help lead them to the realization that if they mark one pole of one of the magnets with tape, they can see how it reacts with both of the other magnets. The poles of the two magnets that are repelled by the taped pole of the third magnet are obviously alike.

Continuing this process, they can determine which poles are alike on all three magnets and mark them with tape. Make sure they test their final solution. (10-15 minutes)

7. To conclude the activity, discuss the notion that although it is possible to determine that like poles repel and unlike poles attract, we could call them anything we wanted to, and North and South are just names. (5 minutes)

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Activity 3: Why does a compass always point north (1 class period)

Integration Notes:
This activity is designed to follow "Discovering the Law of Magnets" and allows students to apply their knowledge of magnets to interpret Earth's magnetic field and to design their own compasses.

Also see the Phase 1 implementation and integration notes for Energy and the Environment for suggestions of electronic resources and ideas for on-line interaction with the Everest team.

Learner Outcomes:
Students will:

• Recognize cardinal directions.
• Classify objects according to whether they are attracted by a magnet.

• a globe
• diagram of Earth's magnetic field

• strong bar magnet
• commercial compass
• jar
• iron filings

• collection of small, metal objects (e.g. paper clip, tack, small nail, penny, pre-1983 nickels, post-1983 nickels, sewing needle)

2. Have them test a variety of metal and non-metal objects to determine which ones "work." Essentially, anything with iron or cobalt will be attracted to the magnet. Because steel is composed of carbon and iron, items made of steel are attracted to magnets. (10-15 minutes)

Note: A fun extension of this part of the activity involves inventing a pop machine that can detect "counterfeit" coins. Give them a collection of nickels from before and after 1983 (in 1983, the metal content of nickels was changed; old ones are attracted to a magnet, and new ones are not). Challenge the students to find out what year the change occurred.

Tell the class that the old nickels (for the sake of the activity) represent counterfeit coins, and that they need to invent a change separator for a pop machine that is able to direct good nickels into a payment slot and divert bad nickels to a return path. Of course, a magnet can be used to divert the old nickels to the return slot, whereas the others fall to the payment slot.

3. Have the students re-examine the commercial compasses. Ask them why the compass needle points north. Discuss the following questions:

• Would it point north from anywhere in the world? (Yes)
• Where would the magnet that produced this effect have to be positioned?
• Just to keep them thinking, you may wish to ask them where north would be if they were standing on the North Pole.

4. Show the students a diagram of Earth's magnetic field to see how well it matches their perceptions. (5-10 minutes)

5. Have each group of students dip their bar magnet into a container filled with iron filings to observe the way the pieces line up. (Or hold the magnet under a non-magnetic container or surface with iron filings on it).

6. Now, relate this pattern to the Earth. Discuss how the pieces would line up on the surface of the Earth if the magnet were inside the Earth. (5-10 minutes)

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Challenge: Make a compass

Integration Notes:
Students should complete " Discovering the Law of Magnets", and "Why does a Compass Always Point North?" activities before attempting the challenge. These preliminary activities will allow them to explore how magnets work and how that relates to how a compass works, before trying to make one.

Also see the Phase 1 implementation and integration notes for Energy and the Environment for suggestions of electronic resources and ideas for on-line interaction with the Everest team.

Learner Outcomes:
Students will:

• · Magnetize a sewing needle.
• Recognize that a freely moving magnet will align itself in a North-South position.

• strong bar magnet
• commercial compass

• sewing needle
• petri dish or small bowl
• small piece of cork or plastic (or something else that floats and would hold up the sewing needle such as a small Styrofoam ball) water

2. Ask students why they think it is important to only move the magnet in one direction. Refer to what they learned about magnets ("Law of Magnets" activity regarding alignment). It may help to make an analogy. Ask them to consider the difference between brushing hair back and forth compared to brushing from the top of the head to the bottom of the hair and lifting at the bottom to start back at the top again.

3. Allow each student to magnetize their own needles. (5-10 minutes)

4. Ask the students why the needle doesn't automatically align itself the way the commercial compass needles do when they lay it directly on the table's surface (it can't move freely).

5. Give each student a petri dish/plastic bowl, water, and a small piece of plastic/Styrofoam ball/cork, and ask them how they might use these materials to solve the problem of the needle not being able to move freely.

NOTE: Suspended on the cork, the needle will align itself to magnetic north.

6. Have them label N, S, E, and W on the compass (container) and practice using the compass.

7. To summarize the lesson, ask the students to brainstorm ideas about how they could improve the compass to make it more practical for use in an outdoor setting. (10-15 minutes)

Back to: Light and Electricity Activities: Division I