Bellwork – 01/22/14
1] Evaporation of rubbing alcohol – physical or
chemical change?
2] Would you add or remove energy ( to/from the
water ) to do this?
** What is the source of the energy?
Bellwork – 01/22/14
1] Evaporation of water – physical or chemical
change?
Physical
2] Would you add or remove energy ( to/from the
water ) to do this?
Add
Grab notebooks/study guides
at front of room
Bellwork:
What are the four states of matter?
Bellwork:
What are the four states of matter?
Solid, Liquid, Gas, Plasma
TN Standards
• CLE.3202.Inq.2 – Recognize that science is a
progressive endeavor that reevaluates and
extends what is already accepted
• CLE.3202.Inq.3 – Use appropriate tools and
technology to collect precise and accurate
data
• CLE.3202.Inq.6 – Communicate and defend
scientific findings
• CLE.3202.1.4 – Investigate chemical and
physical changes
How Does Matter Change
States?
Essential Questions:
• 1] What makes up matter?
• 2] What kind of energy do all particles of
matter have?
• 3] What happens when a substance changes
from one state of matter to another?
• 4] What happens to mass and energy during
physical and chemical changes?
Demonstration 1
• Have cotton balls with rubbing alcohol added
• Student in the front of each row come to the
front and grab enough cotton balls for row
• Each student rub the alcohol on their arm ( skin )
• What happens? What kind of sensations do you
feel?
• Why is this happening?
What is Happening?
Evaporation
• Your body heat gets transferred to the rubbing alcohol
and it evaporates
• This gives that part of your skin a “cooling” sensation
Some Changes Absorb Energy
• Energy is added when water ( or any
substance ):
• Evaporates
• Melts
• Sublimates ( dry ice )
Some Changes Release Energy
• Energy is removed when water ( or any
substance ):
• Condensation
• Freezing
Sweating – Cools Your Body
• So which of the five state changes does
sweating represent?
• Is energy released or absorbed when the
sweating process occurs?
• How does a dog sweat?
Demonstration 2 ( ongoing )
• Will start boiling water in the back of room
• Will take a few notes while water boils
• Once water boils, will add ~butter to it
Changes of State
• The identity of a substance does not change when
the state changes but the energy changes
Active Demonstration
• I will guide you through this
• We will have three groups
• Each group will act like either particles in a gas,
liquid, or solid ( one at a time )
• Each group will stand up and act out this role
Active Demonstration - Results
• Solids: particles vibrate in place
• Liquids: particles move faster than in solid so they
spread out more
• Gas: particles move very fast so they are really far
apart
• Can you walk through ice, water, humid air?
Kinetic Theory of Matter
• Matter is made of atoms and molecules
• These act like tiny particles that are ALWAYS in
motion
• Particles move faster at higher temperatures
• Bigger particles move slower than smaller ones AT
THE SAME TEMPERATURE
Review States of Matter
( Volume & Shape )
• Solids – definite shape and volume?
• Liquids – definite shape and volume?
• Gas – definite shape and volume?
Review States of Matter
( Volume & Shape )
• Solids – definite shape and volume?
– BOTH
• Liquids – definite shape and volume?
– ONLY VOLUME
• Gas – definite shape and volume?
– NEITHER
Solid, Liquid, Gas
Temperature
• Particles in all states of matter have kinetic energy
• Temperature is a measure of the average kinetic
energy of particles in an object
Conservation of Mass & Energy
• Mass and Energy are both CONSERVED ALWAYS
• Mass/Energy is neither created nor destroyed
• This applies to state-changes also
Demonstration 2 ( Butter )
• Of course you know this, but what happens
when the butter is added to the hot water?
• Why does this happen?
• How does energy ( of both the water and the
butter ) change during this process?
• What happens to the particles in both the water
& butter ( speed up or slow down ) ?
Practice - Study Guides
• Pg 10 ( #s 1, 2, 5 )
• Pg. 11 ( #s 1, 2, 3, 4 )
Challenge – In Your Notes
• Fog: which of the 5 state-changes does fog
represent?
• When/Where does fog form
• Is energy absorbed or released when fog forms?
• Is energy and mass conserved when fog forms?
Exit Pass
• On a Whiteboard, make a table with 3 columns
and 4 rows
• list four ( 4 ) common, everyday examples of statechanges in first column
• Put which of the 5 state changes they are in middle
• List whether energy is released or absorbed on
right
Exit Pass
• Draw a picture that indicates a state-change ( you
choose !! ) then label which of the 5 statechanges it is and whether energy is added or
removed [from the substance changing].