Unit 1: Chemistry - Introduction To Surface Tension, Matter, and Energy Flashcards
Variables
Manipulated Variable
Independent Variable –> change or manipulate factor (cause)
Only one MV variable because if multiple, how can you identify cause
Variables
Responding Variable
Dependent Variable –> what you measure in experiments/what is the result (effect)
*Depends on MV, can have multiple RV
Variables
Control Variable
Variables kept same between control and experimental except MV/IV
Surface Tension
Resistance to penetration of surface of liquid (think back to penny drop lab)
Water close to spilling off penny because of gravity and attraction –> maintain “dome” shape
Variables
A cow is given a growth hormone, and compared to another cow that was not given a growth hormone. Both cows were weighed at 2 years. Identify the MV, RV, and CV.
Manipulated (independent) variable = one cow received growth hormone, while the other did not
Responding (dependent) variable = weight of both cows after 2 years
Control variable = same breed of cows, same diet (besides the hormone), same scale
Control group = cow without growth hormone
Variables
One grape is placed in tap water and another grape is placed in salt water. The change in their mass is measured after a day. Identify the MV, RV, and CV.
Manipulated (independent) variable = one grape is placed under tap water, while the other grape is placed in salt water
Responding (dependent) variable = grape’s mass a day after
Control variable = same type of grape, same amount of water, same mass, same time under the water
Control group = grape under salt water
Variables
Pill bugs are placed in a container where they have a choice of a wet or a dry environment. Researchers record how much time was spent on each side. Identify the MV, RV, and CV.
Manipulated (independent) variable = 2 different choices for environment (dry or wet)
Responding (dependent) variable = how much time spent on each side
Control variable = same species of pill bugs, same mass of bugs, even distribution of each environment
Control group = wet environment
Matter
Matter
Anything that has mass and volume
Mass = made of particles (atoms), similar to weight
Volume = amount of space something takes up
ex. Mars, Jupiter, stars, dissolved sugar, air, cells, atoms, oxygen, baby powder, steam
*All mater is made up of particles (atoms/molecules, too small to see)
Matter
Out of the 3 main states of matter, which state (phase) can it hold the shape and volume?
Shape, solid –> definite (cannot change shape)
Volume, solid –> definite
Shape, liquid –> can change (particles allow this because it can flow)
Volume, liquid –> definite
Liquid can flow between containers
Shape, gas –> can change
Volume, gas –> can change (particles allow this because it can flow)
Gas can flow between containters
Matter
What are the characteristics of the 3 main states of matter?
Solid = particles close together, in rigid structure, at bottom of container because of gravity, vibrating, have low energy
*Particles attracted to each other
Liquid = particles pushed around, moving fast, more energy that solids, clump of particles at bottom, while some at top because evaporation, close to each other, edge to edge in container
*less attracted, particles at bottom because of gravity –> not enough energy to go to air
Gas = particles everywhere, bumping into each other often, high amounts of energy, spread apart, no structure, moving fast
*very little attraction to each other
*ALL PARTICLES MOVE IN STRAIGHT LINE UNTIL BUMP INTO OTHER PARTICLES OR CONTAINER
Energy
Energy
Ability to do “work”
Work = moving matter
Energy increases = temperature increases and vice versa
Energy
Temperature
Temperature = average kinetic energy of particles
Kinetic energy increases = temperature increases –> temperature depends on kinetic energy
*On test, hotness and coldness is one of the answers, but it is incorrect
Temperature Scales
What is the temperature of the boiling point?
100 degrees Celsius
212 degrees Fahrenheit
Temperature Scales
What is the temperature of the melting/freezing point of water?
0 degrees Celsius
32 degrees Fahrenheit
Temperature Scales
What is the temperature of room temperature?
20 degrees Celsius
68 degrees Fahrenheit
