What Do You Recall? Physical Science

Station 1 --Investigating Forces Do you know your forces? Non-Contact = Magnetism (opposites attract and likes repel), Gravity (contributes to weight NOT mass). Contact = Friction (Drag) creates ELECTRIC force. Atoms are charged. When the balloons are charged (electrons are stolen!), they are unbalanced, so they seek protons and are attracted to other objects.

Think--What forces are involved in making a hot air balloon move?

Station 2--Observing Motion Forces with causes: Lift = Puck is rising Weight = Gravity (F= MxA) pushing down Thrust = (B) Push with finger, though this is a (Newton’s 3rd law). Push with finger is more APPLIED, BUT we are looking for the motion; Drag = Friction *Remember, balanced forces can be when something is NOT moving, BUT also when something is moving at a constant speed in a straight line (inertia)

When the glider is hovering (but not moving), what forces are balanced When the glider is hovering (but not moving), what forces are balanced? Thrust and Drag AND Lift and Weight. No movement = Balanced. Constant motion is also balanced- -INERTIA!!! 1st Law!!! An object in motion stays in motion, an object at rest stays at rest (at same speed in same direction (velocity) unless acted upon by an unbalanced force! --What must happen to begin movement? A FORCE...needs thrust to initiate (and counter drag). **

--Now that it’s moving, what will happen when all the forces are balanced? It will continue doing what it was...Inertia. --When 2 gliders collide-- -Net force is determined by subtracting. 4 N 2 N Net force = 2 N

Describe the glider’s speed over time (note the axis labels!!!). * Speed is constant until 4 seconds--slope the same. Then the glider slows (flatter slope), then it stops. No change in distance over time.

Station 7 Matter Matters --Protons are the identity! 9 protons = F --Add a proton? Protons are the identity! = Ne --Neutrons do not affect the element! Varying numbers of neutrons mean the atoms are ISOTOPES. = Still Ne --Electrons are EXTREMELY small. --Families (columns) on the periodic table share similar properties!

7--Matter Matters --Solid, liquids, gases Describe each: Solid = vibrations, liquid = flows (but does not fill), Gas = free moving, expands to fill

7- Matter Matters pH 7 = NEUTRAL

7--Think-- What are some similarities and differences between elements, compounds and mixtures? Elements and compounds (compound molecules) are PURE. They can only be separated by CHEMICAL means. Mixtures – Heterogeneous and Homogeneous can be separated by PHYSICAL means (change of state, filter, etc.)

10 --The solar powered race car How should a scientist confirm that an experiment has good (valid and reliable) data? Problem-----Malik and Anthony were testing TWO variables….they had TWO test variables in ONE experiment. --Width and size (C). This INDEPENDENT (TEST) Variable was the variable that the experimenters changed ON PURPOSE, BUT changing TWO variables makes this experiment NOT valid in the first place. The intended DEPENDANT Variable (measured…changed BECAUSE of the independent variable was the speed of the car, as it relied on the tire size (and width unfortunately). Constants are used to be sure that there are no other variables that could affect the results of the experiment. They are the variables that ALWAYS stay the same!

10--Solar powered car The boys who did the experiment and repeated it several times gave it to their friends to do. Their results were similar. This says that the experiment can be REPLICATED! Others do it and get similar results.

11--Think--What are 3 ways that heat can move from one substance to another? radiation - INITIAL transfer of heat to anything! through anything (vacuum) conduction - transferring heat through solids convection - transferring heat through fluids from areas of higher temp to areas of lower temp. (Heat moves cold does not). no such thing as cold only various amounts of heat

11 Radiation is the initial heat transfer. What they are getting at here is if you held your hand near the plate that was initially transferring the heat, that radiation would warm your hand. If you touched someone’s arm after that, conduction would transfer that heat. Convection and conduction are secondary transfers of energy….Radiation is the initial transfer. ie., sun warms the swing at the park (radiation). You sit on it...conduction! Ouch!

11 7 When adding ice, the boiling water transfers its heat to the ice, so the overall temperature drops. Changes in State--

14 --Think-- List several physical properties of matter. density * conductivity * pH color boiling point * melting point * mass Which can identify a pure substance? *Characteristic Properties!

14 Physical Properties of Matter Calculate Density! 20 g/mL = 4 g / x mL? This seemed to stump people. If you are ever not sure how to set up an equation, put in numbers that you can easily solve for and think about how you would solve!

14 Tips-- Solvent = means the substance doing the dissolving (the water in salt water). Solute = the substance being dissolved (salt in salt water). Saturated means dissolved until no more can dissolve so there is extra! Think Kool-aid sludge at the bottom.

15 --Think--What are some similarities and differences in light and sound waves? Both are forms of energy that move as waves (characteristics: wavelength, frequency, amplitude) Sound requires matter to compress Light is slowed by matter

15 Investigating Light and Sound Sound (Compression waves--slinky--back and forth)--NEEDS a medium (something) to travel through. Light (Transverse waves--Up and Down--Think Electromagnetic Spectrum)--DOES NOT need a medium to travel through. Sound (Compression/Longitudinal) Light (Transverse) Amplitude Volume Brightness Frequency Pitch COLOR (or type on the spectrum) Wavelength changes frequency

The Basics

Frequency Change in a Transverse wave *Note change in color!

Frequency Change in a Compression /Longitudinal wave farther apart= lower pitch closer together = higher pitch (second pic)

Amplitude Change in a Transverse wave Lower-Energy (smaller) = Dim Higher-Energy (bigger) = Bright

Amplitude Change in a Compression /Longitudinal wave Lower = Quieter Higher = Louder

Comparison

1= Opaque 2= Translucent 3= Transparent

Sound Light Fastest travel time Solids (knock on the table) Vacuum (sun!!!) 2nd fastest Liquid Gas (air) 3rd Gas Slowest Vacuum (no sound in space) Solid (try to shine a light through the table you knocked on!)

18--THINK-- Describe how energy is converted from one type to another in the production of electricity. Stored potential energy (coal, water, oil) converted to mechanical kinetic energy (spinning turbine) converted to electrical potential energy

18- Battery = Stored potential (chemical) energy converts to electrical. Light bulb = Electrical Energy converts to Radiant (Light or Electromagnetic) Energy -- KNOW ALL NAMES for it. Solar Cell--RADIANT (Electromagnetic/Light energy) converts to electric or thermal. Fan turning--Mechanical converts to electrical

18 Potential = STORED energy Kinetic = MOVING energy

21 Diagram the electromagnetic spectrum, label low/high frequencies and long/short wavelengths. Frequency Changes of Transverse Waves!!!

27 Compare and contrast physical and chemical changes.