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 state-changes 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 state-changes it is and whether energy is added or removed [from the substance changing].