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Students should do science

•Observation

•Measurement

•Collecting, organizing andinterpreting data

Float or Sink?

•Plastic Cubes

•Rock

•Wood

•Clay

•Can of Soda

•Iron

Learning Cycle

Exploration•Open ended

•Social Interaction

Concept Invention or Formation•Guided Activities leading to formation of concept

Application•Use the concept learned

Essential Features of ClassroomInquiry

1. Learners are engaged by scientifically oriented questions.2. Learners give priority to evidence, which allows them to

develop and evaluate explanations that addressscientifically oriented questions.

3. Learners formulate explanations from evidence toaddress scientifically oriented questions.

4. Learners evaluate their explanations in light ofalternative explanations, particularly those reflectingscientific understanding.

5. Learners communicate and justify their proposedexplanations.

Formal Level (Proportional Reasoning)

ConceptsThe distance between two points ismeasured to be 10 dk green rods.What is the distance in terms of•Lt green•Red•Violet•Yellow

Answer this question bylooking at the relationshipsbetween rods. Do not actuallymeasure.

This is proportional reasoning

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This is proportional reasoning

How many 2’sare in 10? Eachof these is 3violets

How many 5’s are in 10?

Using Units in Science

5 cm x 2 cm=? 10 cm2

2 cm2

3 pears per orange

What is heavier?

•A pound of wood or a pound of iron?

•Wood or iron?

ft3, cm3, m3If you have 20 cubes,and they weigh 40 gall together, howmuch does one cubeweigh?

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Finding mass of 1 cube

Ratio 5gm 1cm32cm3=___ gm, 5cm3= __gm

10 gm= __cm3, 25 gm=__ cm3

Density• The density of a substance of uniform composition is

defined as its mass per unit volume:

• Units are kg/m3 (SI) or g/cm3 (cgs)• 1 g/cm3 = 1000 kg/m3

Density of water = 1 g/cm3 = 1000 kg/m3=32 lbs/ft3

How much does the Earth weigh?An average piece ofthe earth like a rockhas a density of

D=2.5 gm/cm3

The earth has a volume ofapproximately

V= 1027 cm3

Since every cube weighs about 2.5 gram and we have 1027 cubes

The mass of the earth is about 2.5 gm/cm3 x 1027 cm3

2.5 x 1027 gramsgrams

Float or Sink? Why?

•Plastic

•Wood

•Clay

•Metal

Densities of different materials

0.6-0.9wood2.4-3.1stone

1.0Water at 40.92ice1.025Salt water11.4lead0.9oils7.87Iron13.6mercury8.96Copper0.8alcohol2.7Aluminum

Density(gm/cm3)

LiquidsDensity(gm/cm3)

Solids

Why do things float/sink? How is density related to floating andsinking?

Properties of Matter

Are any of the liquids the same substance?Write a scientific explanation that answers the question.

no color-98 ºC0.93 g/cm316 gLiquid 4

silver-39 ºC13.6 g/cm321 gLiquid 3

no color26 ºC0.79 g/cm338 gLiquid 2

no color-98 ºC0.93 g/cm338 gLiquid 1

ColorMeltingPointDensityMass

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Identifying theFeatures of Inquiry

Where in the previous activity was each of thefive features exemplified?

Questions Evidence Explanations Connections to scientific knowledge Communication and justification

The Graduated CylinderIf a stone is dropped, waterlevel goes up

Archimedes uncovered a fraud in themanufacture of a golden crowncommissioned by Hiero II, the king ofSyracuse. Suspecting that the goldsmithmight have replaced some of the goldgiven to him by an equal weight of silver,Hiero asked Archimedes to determinewhether the wreath was pure goldBecausegold has a density of 19.3 grams/cubic-centimeter,

Floating Wood

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Float/Sink At various gradelevels

Changing Density

Example:Empty sodacan vs full

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Mixed Densities

• Metal balls inside jarsink

• What happens if younow put in styrofoam?

Volume is fixed butMass varies

• What happens if weadd mass to theoutside of thecontainer?

Changing Density

Example:Empty sodacan vs full

A bloc of wood floats in water.If holes are drilled in the wood the block will

•Sink

•Float Higher

•Float Lower.

•Float the same

Essential Features of ClassroomInquiry

1. Learners are engaged by scientifically oriented questions.2. Learners give priority to evidence, which allows them to

develop and evaluate explanations that addressscientifically oriented questions.

3. Learners formulate explanations from evidence toaddress scientifically oriented questions.

4. Learners evaluate their explanations in light ofalternative explanations, particularly those reflectingscientific understanding.

5. Learners communicate and justify their proposedexplanations.

Heat and ExpansionWater is an exception

How would this affect the density of water?

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• Water is the exception• Increase the

temperature of anycommon liquid and itwill expand.

• But not water attemperatures near thefreezing point: Ice-cold water does justthe opposite!

At what temperature is watermost dense?

Just below 0｡C, when water has becomesolid ice, its volume is considerablylarger, and its density smaller

• As water cools, it sinks until the entire pond is 4｡C.Then, as water at the surface is cooled further, itfloats on top and can freeze. Once ice is formed,temperatures lower than 4｡C can extend down intothe pond.

Misconceptions re Density, F/SStudents focus on only one variable, mass or volume, ratherthan relationship between these two.

Some common misconceptions

•Size

•Shape

•Material

Variations: Orange, Float or Sink?

Popcorn, Float or Sink?

Real reason for F/S: Archimedes Principal

The increase in water level is the same as thatwhich would occur if, instead of putting thestone in the container, we had poured in avolume of water equal to the stone's volume

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Archimedes Principal: An object in afluid experiences an upward force equalto the weight of the fluid it displaces.

Totally Submerged Object• The object is pushed up by a

force called the buoyant (B)force.

• This force (B) is equal toweight of water displaced.

• B may be bigger than w• B may be smaller than w.• B may be equal then w

What is the Buoyant force? Archimedes Principal Demo

• Iron is muchdenser thanwater. A solidchunk of ironsinks, as youwould expect,but an iron shipfloats. Why?

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The Bouncing ballVariables: Independent and Dependent

Line Going thru origin

Y=mX where m is slope, 2 in this case

Line Not Going thru Origin

Y=mX + b where b is y intercept

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Thermometers and Temperature Scales

• The mercury or alcohol-based one you see here relieson the fact that mercuryexpands at a predictable ratewith temperature. The scaleof the thermometer measuresthe amount of expansion.

Heat and Temperature

220

200

180

160

140

120

100

80

60

40

20

0

F

100806040200

C

C

Y=mX + bF=mC + b

F vs C

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Non- Linear Relationships

Y=Xn

Science Skills

• Observation• Communication• Use of measuring instruments• ANALYSIS AND REPORTING OF DATA

IT IS THE JOB OF THE TEACHER TO PROVIDE AENVIRONMENT WHERE THIS CAN TAKE PLACE

NSF Standards k-4From the earliest grades, students shouldexperience science in a form that engagesthem in the active construction of ideasand explanations

As a result of activities in grades K-4, allstudents should develop

* Abilities necessary to do scientific inquiry * Understanding about scientific inquiry

Science Process Skills•Identify Variables

•Propose Hypothesis

•Plan and conduct controlledexperiments

•Collect, organize and present data

•Communication

•Generate conclusions and/or predictions

Motion of Earth