Constructing Ideas in Physical Science Joan Abdallah, AAAS Darcy Hampton, DCPS Davina Pruitt-Mentle, University of Maryland CIPS Institute for Middle School Science Teachers

AAAS/DCPS CIPS Workshop8/2-8/13 2 Session 2 Debriefing What do you remember from yesterday’s session (no peeking at text or notes)? What were the “essential questions” being asked/explored? What conclusions did “we” decide? What was/were the “underlying concepts/content” that the activities were after?

AAAS/DCPS CIPS Workshop8/2-8/13 3 Deeper Questions What deeper questions could you envision students asking? What misconceptions or misinterpretations can you foresee? How or what would you say?

AAAS/DCPS CIPS Workshop8/2-8/13 4 Deeper Questions or Possible Misinterpretations “What is a magnet”? “What makes something a magnet”? “How can you magnetize something”? “How does something loose being a magnet”? What would you say?

AAAS/DCPS CIPS Workshop8/2-8/13 5 What’s a Magnet? Magnets do the following things: Attract certain materials - such as iron, nickel, cobalt, certain steels and other alloys; Exert an attractive or repulsive force on other magnets Have an effect on electrical conductors when the magnet and conductor are moving in relation to each other; Have an effect on the path taken by electrically charged particles traveling in free space. The Magnet Library ng/new_lib/lib_1.htm

AAAS/DCPS CIPS Workshop8/2-8/13 6 Why does a Magnet Work? Iron, Cobalt, and Nickel (and some other elements), as well as some alloys are ferromagnetic These materials exhibit a property called long range ordering –This is a quantum effect beyond the scope of a middle (or high) school class –Unpaired electrons in the material tend to line up –Electrons which line up cause the magnetic effect

AAAS/DCPS CIPS Workshop8/2-8/13 7 Iron Fe #26

AAAS/DCPS CIPS Workshop8/2-8/13 8 Cobalt Co #27 From Web Elements

AAAS/DCPS CIPS Workshop8/2-8/13 9 So Why isn’t all Iron Magnetic? Usually, due to random effects, this electron spin alignment is limited to regions This randomness leads to no net magnetic field Electrons in different directions

AAAS/DCPS CIPS Workshop8/2-8/13 10 How do we make it a magnet? Add an Electric Coil Wire coils with electricity through them create a magnetic field which runs through the center This tends to align the domains (of lined up electrons) in the same direction The greater the current, the greater the magnetic field Iron (or other ferromagnetic elements) tends to amplify the magnetic field

AAAS/DCPS CIPS Workshop8/2-8/13 11 Now it stays magnetic after we remove the wires The electric field makes the domains line up When you remove the coil, the domains tend to stay aligned –This property is called hysteresis

AAAS/DCPS CIPS Workshop8/2-8/13 12 Earth’s Magnetic Field

AAAS/DCPS CIPS Workshop8/2-8/13 13 Want To Learn More? What Makes Earth a Magnetic Force? Magnets and Electromagnets Electricity and magnet playwiths Magnetic Expressions Ohio State’s Virtual Demo Lab (also scroll to end for list of other online simulation sites)Ohio State’s Virtual Demo Lab

AAAS/DCPS CIPS Workshop8/2-8/13 14 Can We Apply What We Learned Yesterday? Class Activity 1.Battery PowerBattery Power 2.WHICH TILE CLEANER REMOVES SOAP SCUM THE BESTWHICH TILE CLEANER REMOVES SOAP SCUM THE BEST 3.The Science of WaterThe Science of Water 4.What Can Affect One’s Perception of SoundWhat Can Affect One’s Perception of Sound 5.Why does junior tennis have such a high injury rate?Why does junior tennis have such a high injury rate? Judge these using the rubric provided

AAAS/DCPS CIPS Workshop8/2-8/13 15 More Fun A Science Fair How Not to Guide – Montykins – Bogus Entries are Fair Game –