matter and energy chapter 3.1. what do you think of when you hear the word… kinetic
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Kinesiology (scientific study of biological movement) Kinesthetic learning (learning by doing/tactile learning/learning by physical movement)TRANSCRIPT
Matter and Energy
Chapter 3.1
What do you think of when you hear the word…
Kinetic
Kinesiology (scientific study of biological movement)
Kinesthetic learning (learning by doing/tactile learning/learning by
physical movement)
So what does kinetic mean?• Motion!• So what is the kinetic theory of matter? – Theory of the motion/movement of matter • 3 common states of matter:• A) Gases• B) Liquids• C) Solids
• 4th state of matter? – Plasma!
3 Main Parts of the Kinetic Theory
• 1. All matter is made up of atoms and molecules that are always in constant motion
Kinetic Theory…
• 2. The higher the temperature of the substance, the faster the particle moves
Kinetic Theory• 3. At the same temperature, more massive
(heavier) particles move slower than less massive (lighter) particles
Who would win?
Diamond
Solids—definite volume, definite shape• Particles in a solid are in a fixed position (even
though they are still moving!—they just vibrate) • Structures of solids are rigid – Crystalline Solids—have an orderly
arrangements of atoms or molecules • Ex: Iron, Diamond, and Ice
– Amorphous Solids—composed of atoms and molecules that are in no particular order • Ex: Rubber and Wax
Rubber
Liquids—definite volume, not shape• Particles of a liquid can slide past each other, so
the shape of a liquid changes • Particles move faster than in a solid, overcoming
the forces of attraction between the particles (allowing particles to flow freely)
• Liquids take the shape of their container, but the volume does not change!!
Another property of water…
• Surface tension!—force acting on the particles that cause the particles to stick together on the surface
Gases- no definite volume or shape • Particles are free to spread in all directions• What would happen if I sprayed perfume at
the front of the room? – The gas particles will expand to fit the room, and
eventually you will all smell it! • Gas changes in volume and in shape!
How many balloons can one helium tank fill?
700! Gases change both their shapes and volumes, and once they are under less pressure and in a wider space, they can expand!
Plasma• Believe it or not…– Plasma is the most common
state of matter!...more than 99% in the universe!
• Where is plasma found?– Sun, stars, lighting, fire, aurora borealis
• Plasma does not have a define shape, the particles have broken apart, and they can conduct electric currents! – So, similar to gases except that gases cannot
conduct an electric current!
Energy • Energy is the ability to change or move
matter (to do work)
• Thermal energy = the total amount of kinetic energy of the particles that make up a substance
Temperature
• What is temperature?• Scientifically, temperature is
the measure of the average kinetic energy of the particles in an object
• Hot temperatures = particles moving faster = greater amount of kinetic energy
Change of State• Chemical or Physical Change?–Physical! • The identify of a substance does not
change, only the amount of energy of a substance • If energy is added = particles move faster• If energy is removed = particles move
slower
Water—Which state has the most energy?
• Go from solid to liquid by adding heat!• Go from liquid to gas (Steam) by adding heat!• A transfer of energy (known as heat) leads to a
change of state• Draw this in
notebook
Changing state with energy• Endothermic changes—changes that result
from adding heat – Example: A solid changing to liquid by the
addition of heat atoms vibrate faster and break apart from their fixed positions (melt)
– Melting point—temperature at which a substance changes from a solid to a liquid
– Melting point of water? 0°Celsius
Changes of State• Evaporation—change of state from a liquid to
a gas (ex: boiling)– Boiling point of water at sea level = 100°Celsius
• Sublimation—the process by which a solid turns into a gas – Example: Dry ice (solid carbon dioxide)
sublimes to form gaseous carbon dioxide
Changes of State• Other changes can occur by releasing heat =
exothermic reactions • Condensation change of state from a gas to a
liquid• Water molecules slow down, and
a large amount of atoms clump together
• Freezing change of state from a liquid to a solid– Water molecules slow down further, and the attraction
between particles overcomes their motion
Changing States..
• When a substance loses or gains energy, either its temperature changes OR it is changing states (NOT BOTH)
• When changing states, temperature stays the same
• If you add heat to ice at 0°C, the temperature will not rise until the ice has melted
