Dr. Joseph W. Howard ©2008 Science & the Physical World When you look around the room, what do you see? When you look around the room, what do you see? Can we “categorize” anything? Can we “categorize” anything? Can we relate seemingly different things? Can we relate seemingly different things? What does everything in the room have in common? What does everything in the room have in common?

Dr. Joseph W. Howard ©2008 Scale Up! Scale Up! Room Room Building Building Campus Campus City City Universe Universe Scale Down! Scale Down! Room Room People People Chair Chair Dust Dust Chalk Chalk Atom Atom

Dr. Joseph W. Howard ©2008 Scales in Science Scales in Science We can explore three scales  Macroscale Objects the human eye can easily “see” with the naked eye. [[~millimeter  bigger]]  Microscale Objects you need a “microscope” to “see.” [[~ m  0.001m]]  Nanoscale Very tiny – nearly impossible to “see” using very fancy scientific equipment. [[~ m  smaller]] Which scale is the most responsible for everything that occurs in the physical world? –Microscopic and macroscopic behavior determined by objects at the nanoscale level We can explore three scales  Macroscale Objects the human eye can easily “see” with the naked eye. [[~millimeter  bigger]]  Microscale Objects you need a “microscope” to “see.” [[~ m  0.001m]]  Nanoscale Very tiny – nearly impossible to “see” using very fancy scientific equipment. [[~ m  smaller]] Which scale is the most responsible for everything that occurs in the physical world? –Microscopic and macroscopic behavior determined by objects at the nanoscale level

Dr. Joseph W. Howard ©2008 Closer Look at the Nanoscale Closer Look at the Nanoscale Consider a piece of ice from our macroscopic view

Dr. Joseph W. Howard ©2008 Closer Look at the Nanoscale Closer Look at the Nanoscale This is a tiny piece from the block of ice Consider ice from a nanoscale view Consider ice from a nanoscale view

Dr. Joseph W. Howard ©2008 Looking at the Nanoscale: Divide block of ice in half

Dr. Joseph W. Howard ©2008 Looking at the Nanoscale: If divided over and over, eventually reach smallest particle that is a particle of ice the water molecule If divided over and over, eventually reach smallest particle that is a particle of ice the water molecule

Dr. Joseph W. Howard ©2008 NanoScale Stuff Chemical compounds atoms molecules particles Periodic table protons electrons

Dr. Joseph W. Howard ©2008 Molecules are composed of atoms Some substances have atoms, but not molecules as their fundamental particle Elements –substances that consist of only one type of atom –Mercury for example Molecules are composed of atoms Some substances have atoms, but not molecules as their fundamental particle Elements –substances that consist of only one type of atom –Mercury for example Looking at the Nanoscale: The Fundamental Particle

Dr. Joseph W. Howard ©2008 Looking at the Nanoscale: The Fundamental Particle Compounds –molecule is fundamental particle –two or more different types of atoms chemically bound together in the molecule –ice for example Compounds –molecule is fundamental particle –two or more different types of atoms chemically bound together in the molecule –ice for example

Dr. Joseph W. Howard ©2008 Looking at the Nanoscale: The Fundamental Particle Pure substances and mixtures –mixtures have more than one type of fundamental particle present All substances are made of atoms, but the atom is not necessarily the fundamental particle of the substance Pure substances and mixtures –mixtures have more than one type of fundamental particle present All substances are made of atoms, but the atom is not necessarily the fundamental particle of the substance

Dr. Joseph W. Howard ©2008 How Big is an Atom? Typically about m long 1 atom of Cu weighs lb Typically about m long 1 atom of Cu weighs lb In Scientific Notation, m is 1 x m lb is 2.33 x lb In Scientific Notation, m is 1 x m lb is 2.33 x lb

Dr. Joseph W. Howard ©2008 Scientific Notation Scientific Notation 1 hectogram = 1  10 2 grams= 1  10  10 = 100 grams 5,100,000 fish = 5.1  1,000,000= 5.1  10  10  10  10  10  10 fish = 5.1  10 6 = 5.1 mega-fish 1.23 picoseconds = 1.23  seconds = seconds

Dr. Joseph W. Howard ©2008 Changing Units Changing Units Often you will need to change one unit to another unit. How many quarters are in $5? (US) You actually do this every day! Unit Conversion(Keep track of the factor labels) 5 dollars= 20 quarters[ I multiplied! ] 60 eggs = 5 dozen [ I divided! ] How many dozen are in 60 eggs?

Dr. Joseph W. Howard ©2008 Example Example How many seconds are in 1 earth day? 1 day= 86,400 secs 8.64  10 4 seconds

Dr. Joseph W. Howard ©2008 Example Example Being a young entrepreneur you go into business operating a “kissing booth” at the local carnival and charge 50¢ for every kiss. How many dollars do you make if you sell 2.3 kilokisses? 2.3 kilokisses = 2.3  10 3 kisses= 2.3  1000 kisses = 2300 kisses 2300 kisses= $ 1150

Dr. Joseph W. Howard ©2008 1x m one fermi 1 fm1x mdiameter of proton (in the nucleus) 2.2 fm2.2x mclassical diameter of neutron 3.8 fm3.8x mdiameter of the nucleus of a helium atom fm x mclassical diameter of an electron 7.2 fm7.2x m diameter of the nucleus of an aluminum atom 14 fm1.4x mdiameter of the nucleus of a gold atom How small is small ? How small is small ?

Dr. Joseph W. Howard © mm2x10 -3 mdiameter of a large grain of sand 2 mm2x10 -3 msize of a small ant mm4.234x10 -3 mheight of a line of text in 12-point type 10 mm1x10 -2 mone centimeter 1.7 cm1.7x10 -2 m wavelength of 20khz note (highest that can be heard) at 27 degrees celsius 2.5 cm2.5x10 -2 msize of a large ant 2.54 cm2.540x10 -2 mone inch 8.5 cm8.5x10 -2 mlength of largest human chromosome if it were stretched end-to-end 12.2 cm1.22x10 -1 mwavelength of microwaves in a microwave oven 30 cm3.0x10 -1 mone foot 79 cm7.9x10 -1 m wavelength of 440 hertz note (A above middle C) at 27 degrees celsius 91 cm9.1x10 -1 mone yard 1 m one meter How small is small ?

Dr. Joseph W. Howard ©2008 Pluck a hair from your head. Examine that single strand of human hair. Now imagine slicing that hair lengthwise into 10 strips. Each piece would be too small to see with the naked eye and would be about as wide as a typical human cell, about 5 millionths of a meter. Now cut one of those slices 10 more times, and you've reached the limit of vision of the best optical microscopes. But now comes the big step. Take one of these strips and cut it 1,000 more times. The resulting pieces now contain only a few atoms -- and you've entered the nanoscale realm. This means there are about 10 5 atoms across the width of a human hair. The same number of hairs (10 5 ) put side by side would be 5 meters in length. The average human head has 10 5 hairs. (Looked it up) 10 5 meters is 62.2 miles Pluck a hair from your head. Examine that single strand of human hair. Now imagine slicing that hair lengthwise into 10 strips. Each piece would be too small to see with the naked eye and would be about as wide as a typical human cell, about 5 millionths of a meter. Now cut one of those slices 10 more times, and you've reached the limit of vision of the best optical microscopes. But now comes the big step. Take one of these strips and cut it 1,000 more times. The resulting pieces now contain only a few atoms -- and you've entered the nanoscale realm. This means there are about 10 5 atoms across the width of a human hair. The same number of hairs (10 5 ) put side by side would be 5 meters in length. The average human head has 10 5 hairs. (Looked it up) 10 5 meters is 62.2 miles How small is small ?