Substances*with*a*p H*below*7*are*called *Acids.*Substances*w ith*a*pH*above*7*ar e*called*Bases.*Subs tances*with*a*pH*of*7*are*Neutral.**Water*is*
the*only*neutral*sub stance.*
*
The*pH*scale*actuall y*measures*the*amou nt*of*HYDROGEN5IO NS5(H+)5that*are*pr esent*in*a*solution.*pH*could*stand*for*“T HE$POWER$OF$
HYDROGEN.”**The$lower*the*pH *value,*the*greater*the*amou nt*of*hydrogen*ions*(H+)*present*in*the*solution5
*
You$CAN$Pass$Your$Biology$SOL!$
Scientific Method
Step$1:$Make*an*OB SERVATION.**The*tw o*
***************types*are:*
*
$→QUALITATIVE:$$Des criptions**
* *****without*number.*(Ex)*The**
******book*is*heavy.*
$→QUANITATIVE:$Descriptions**
*** *****that*use*numbers.*(Ex)*The**
* *****book*has*250$pages.*
*
Step$2:$Make*a*HYP OTHESIS.$$This*is*an **
***************educated*guess*based*on**
***************qualitative*a nd*quantitative*dat a.*
*
***⇒*Scientist*should*look*for*2**
*********variables*in*try ing*to*find**
*********answers*to*the*problem.*
*
*◊INDEPENDENT$VAR IABLE$(IV)$
$$$$$$OThe*thing*I*change*
$◊DEPENDENT$VARIA BLE$(DV)$
$$$$$$OThe*thing*I*measure$
*
$
Step$3:$Setup*a*CON TROLLED$$
$$$$$$$$$$$$$$$EXPERIMENT.**Each*has:*
**
1. CONTROL$GROUP:$t he*group*
that*stays*the*same*( doesn’t*
receive*the*IV).**It’s*n eeded*to*
compare.*
*
2. EXPERIMENTAL$GROUP:$the*
group*that*is*manipulated*(the*
group*you*are*performing*the*
experiment*on).**This*group*
receives*the*IV.*
*
Step$4:*Make*a*CON CLUSION*or*THEOR Y$
$
⇒If*the*data*gathered*from*your**
*****controlled*experiment*support*
*****your*hypothesis,*y ou*accept*
*****your*conclusion.*
⇒If*the*data*doesn’t*su pport**
*****your*hypothesis,*s tart*over!*
How$to$Identify$Variables$on$
a$Graph:$
*****Scientists*use*the$SCIENTIFIC$METHOD$to*help*them*answer*questions*and*solve*problems*about*the*natural*world.******
*
*
*
………………………………………………………………………….*
*
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YOaxis$is$the$DV.$
The$thing$I$measur e$
XOaxis$is$the$IV.$
The$thing$I$change$
*Water*makes*life*possible!**It’s*a*universal*solvent,*comes*in*three*states,*and*has*a*high*specific*heat*to*regulate*temperature**
*
The*chemical*formula*of*water*is*H2O.$$It*
has*2*hydrogen*and*1*oxygen.*
$
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*
*
Water*has*a*positive *side*(hydrogen)*and *a*
negative*side*(oxyge n).***These*charges*
allow*water*to*stick *to*other*things*that*
also*have*a*charge.*
*
HYDROGEN$BONDS*hold*water*to*itself*
and*to*other*charged *substances.*
*
*
When*water*sticks*to*other*things*(like*a*
car*window)*ADHES ION*is*taking*place.*
*
When*water*sticks*to*itself*COHESION*is*
taking*place*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
**
$
Water*comes*in*3*sta tes:*solid,*liquid*or*
gas.**In*the*solid*stat e*(ice),*water*is*less*
dense*than*the*liquid*state.**Ice*floats!*
*
Water*has*a*HIGH$SPECIFIC$HEAT.**It*ca n*
absorb*a*lot*of*energ y*without*increasing*
its*own*temperature .**This*is*why*water*
takes*so*long*to*boil !*
*
We*use*this*property *to*help*us*
regulate*our*body*te mperature.**
When*our*body*temperature*gets*
too*high,*we*start*to*PERSPIRE*
(sweat).***
*
We*do*not*want*our*body*temperature*
to*fluctuate*very*much*because*it*
would*alter*chemical*reactions*
(METABOLISM).*When*
metabolism*is*thrown*off,*
HOMEOSTASIS$(balance)*is*also*
thrown*off.*This*can*lead*to*death!!!!*
$
Water & its Properties
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pH Scale
