Magnetism Shaw STEM Lab 2015

Things You’ll Learn How magnets work The two sides of a magnet How magnets can effect a compass How Maglev trains operate

Background Information Imagine getting in a bullet-shaped train and gliding to your destination at almost 500 kilometers (300 miles) per hour. Magnetism could make it possible. In the early 1960s, two American scientists patented a new kind of train called a maglev train. The name stands for “magnetically levitated train,” because the train floats just about the track.

Do It & Research Check out the two bar magnets. Examine the magnets, they are marked “S” (south) and “N” (north). Place both north poles together, then both south poles together, and one north pole and one south pole together. Describe what happened for each of the three examples North and North South and South North and South

Background Information All aboard the “Maglev Express,” the world’s fastest train, propelled through the air by magnets! How does maglev work? The process is repulsive. Repulsion is a property of magnetism. In the case of the maglev train, electromagnets (coils of wire magnetized by electric currents) on the bottom of the train repel, or push against, other electromagnets in the guideway tracks. That causes the train to float!

Background Information To propel the train forward, an alternating current of electricity flows through coils in the guideway walls. The current causes each coil to change its polarity (North to South, South to North) as each train magnet passes. When the train and guideway magnets line up N-N or S-S, the result is repulsion, or a push forward. All that pushing and pulling makes maglevs fly! To make the train speed up or slow down, engineers controlling the railway increase or decrease the amount of electric power fed into the track. That cause the speed at which the magnetic wave travels underneath the train.

Background Information Click the link below to watch a short film about Maglev trains.

Do It & Research Check out the floating magnets kit. Make two magnets float as shown in the picture to the right. Describe what makes the magnets float. Measure the distance between the magnets-record this information. Join two of the magnets together and make the third magnet float. Measure the distance between the magnets-record this information. Is this distance more or less than the previous experiment? Describe your reasoning. Continue joining the magnets one at a time while floating another. Measure the distance after joining each magnet-record this information. Are the magnets becoming closer or further away? Describe why this could be happening. Explain what would happen if we were to add more magnets.

What makes something magnetic? Imagine a factory that makes little bar magnets and ships them out. A truck driver named Dave transports these magnets in cardboard boxes. Dave doesn’t have time to worry which way the boxes are stacked, so he piles them inside his truck any which way. The magnets inside one box could be pointing north while the one next to it is pointing south, east, or west. Overall the magnets are all jumbled up, so even though magnetic fields leak out of each box, they all cancel each other out.

What makes something magnetic? Another driver named Bill loads his truck very neatly. Bill stacks all the boxes in the exactly the same way. The magnetic field of one box will align with the field from all the other boxes. This makes the truck into one giant magnet. These two trucks are large examples of what happens inside magnetic materials. A substance like aluminum contains lots of tiny pockets and therefore its “boxes” are arranged randomly-therefore it is not magnetic. A substance like iron however has all of its “boxes” lined up and is therefore magnetic.

Do It & Research Check out the metal samples and a magnet. Test each of the metal samples with the magnet and record your findings in a table. Find four more samples of your own and test if they are magnetic or not and record your findings in the same table. Material To Be Tested Magnetic or Not Iron Zinc Aluminum Copper Your Sample #1 Your Sample #2 Your Sample #3 Your Sample #4

Do It & Research Gather the following to assemble your car Red or Blue Levitator Car Template Card Stock Four (4) Ceramic Magnets Transparent Tape Scissors Double-sided Tape Gather the following to test your car Mag Lev Track Meter Stick Text Books Stop watch Meter Tape

Do It & Research Assemble the Base For Your Car In each of the four corners of the card stock, attach one (1) magnet with double-sided tape After the magnets are in place, hold the card stock over the magnet strip on the Mag Lev Track. The magnet strip should repel the magnets attached to the card stock. If any of the four ceramic magnets are attracted to the magnetic strip, remove the ceramic magnets from the card stock, flip them over, and reattach them on their other side so they repel the strip. Now, the card stock should float (levitate) over the track

Do It & Research Assemble the Body Score along the five solid lines on the Levitator Car Template. Using scissors, cut along the dotted lines of the template. Cut out the body and wings (white flaps, outside edges, wing slots). Fold the body in half, done the centerline. Tape the nose and windshield areas to hold them in place. Fold the flaps inward, toward the center, to form the base of the car. Attach the flaps to the card stock with double-sided tape. Fold the wings and place them in the wing slots, with the logos on the top facing toward the back.

Do It & Research Measure the distance of the Mag Lev Track Raise one end of the Mag Lev Track to a height of 15 centimeters with textbooks. Place your Mag Lev Car at the top of the track and time how long it takes to travel the distance of the Track-record this information in a table (example is shown on the next slide.) Repeat this with the height of the track raised to 30 and 45 centimeters. Record the information of each of these trials. Calculate the speed of your car for the trials. Speed = Distance of the track / Time it took your car to travel

Time it took car to travel Do It & Research Height of Track Distance of Track Time it took car to travel Speed 15 Centimeters 30 Centimeters 45 Centimeters

Do It & Research Describe in at least five (5) sentences what conclusion you can make about the speed of your car as you raised the height of the track. Explain in at least five (5) sentences modifications you could make to your Mag Lev Car to make it travel faster. After explaining your modifications, try them out! Be sure to record your findings in a separate table.