LEVEL 3 CONTENT-BASED LEVELED READER
SWEAT IN T FO EX RM ATIONAL T
WHY DO WE
SWEAT? KID E-LIT
WHY DO WE
SWEAT?
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Word List temperature hot warm blooded sweat cold blooded bright red inside pig evaporate brains glands dilate liquid blood vessel pores expand body
rise shiver movement lizard snakes drop muscle environment tissue drink molecule water energy exercise gas fluids animals
Whew! It's so hot!
I'm bright red!
I'm sweating like a PIG! WHEW SO H ! It's OT!
Why do we sweat?
Internal Temperature
3 7 °C
Internal Temperature
3 7 °C
Humans are warm-blooded -- this means our internal temperature always stays the same. Around 37°C or 98.6°F is a normal internal temperature.
Internal Temperature
3 8 °C
Snakes
Internal Temperature
Lizar ds
3 3 °C
Some animals are cold-blooded. This means that their internal temperature varies, or changes, according to the temperature of their environment. For example, lizards and snakes are cold-blooded.
Internal Temperature
3 7 .2 °C
rnal e t x e The rature tempe RISES.
Internal Temperature
3 7 .1 °C
ternal n i r u O ature r e p m te RISES.
Internal Temperature
3 7 °C
When it gets hotter, and the external temperature of our environment rises, our internal temperature rises too.
External Temperature
3 8 .9 °C
pes a c s e Heat e from th body.
Internal Temperature
3 7 °C
When our internal temperature rises above 37°C, we sweat. Our sweat allows heat to escape from the body and our internal temperature returns to 37°C.
External Temperature
1 0 °C
B rrrr!
r e v i sh
When it gets cold, our internal temperature drops below 37°C, and we shiver.
rnal Our inetre re temp baatcuk up. goes
In Tempteernal ra tur e
g Shiverin tes genera heat.
37°
C
These shivers are contractions of the muscles. This movement generates heat which makes our internal temperature go back up. shivers nt co ractions of the muscles
B ra
T
in
al re n r e Ext era tu em p
B lo
o
ss e V d
els
37°C
When the external temperature rises above 37°C, our brains send a signal to our blood vessels.
B r a in B
esse V d o o l
ls
D ila t e
Exp an
d
This signal causes the blood vessels to dilate. This means that the blood vessels expand, or get bigger.
t Hea apes esc m the fro dy. bo
When they dilate, our blood vessels allow heat to escape from the body more easily and faster.
Sweat
Sw ea
Pore t Swead G la n
t
Pore
Sweat Gland
Sw eat Pore
Sweat Gland
At the same time, our sweat glands fill with water that they pump to the exterior of our bodies. Sweat comes out of the pores in our skin.
Sweat
Sw eat
37.4°C
Pore t Swead G la n
Sw ea
Sw eat
t
Pore
Pore
In Tempteernal ra tur e
Sweat Gland
3 7 .4
°CSweat
The sweat is the same temperature as our internal temperature.
Gland
Internal re Tem p era tu Intern al Tempe rature
3 7 .4
°C Intern al Tempe rature
Sw eat
37.4°C
3 7 .3
°C Intern al Tempe rature
3 7 .2
°C Intern al Tempe rature
3 7 .1
°C Intern al Tempe rature
37°
C
How does sweat cool us off, if it is the same temperature as our internal temperature?
Gas
W a ter V a p
Sw eat
E v a p o r a t io
or
er t a W d i u q i L
n
Our sweat evaporates. The water changes from liquid into gas, or "water vapor".
Gas
W a ter V a p
or
EN ERG Y Sw eat
E v a p o r a t io
er t a W d i u q i L
n
To change from a liquid to a gas, the water molecules need energy.
W a ter H eat
L iq u id
E
V apor
n o i t a r vapo
H eat
W a ter
ENERGY
He
at
T is s u e s The molecules of liquid water capture heat from our tissues.
Internal re Tem p era tu
H eat
Whew !
Intern al Tempe rature
3 7 .4
°C Intern al Tempe rature
3 7 .3
°C Intern al Tempe rature
ENERGY
3 7 .2
Ahhhh ...
°C Intern al Tempe rature
3 7 .1
°C Intern al Tempe rature
s e u s s Ti
Reduced
37°
C
Our tissues get cooler. Our internal temperature is reduced, and we feel cooler.
External Temperature
3 9 °C
Internatlure a Tem per
3 7 °C
That is how sweat maintains our internal temperature at 37°C or 98,6°F when the external temperature rises above 37°C.
So when you feel sweat on your body you can rest assured it is a good thing.
We do need to be careful when we exercise and sweat a lot. We have to drink more fluids to stay hydrated. Hydration is replacing the lost fluid in our body from sweating.
Be sure to drink plenty of water when exercising or working in the heat. WATER does a body good!