Transcript 7 Science Chapter 4 Notes

Unit 2: Heat
Chapter 4: Temperature
describes how hot or
cold an object is.
How
does
temperature affect
your daily life?
Why
do you feel
warm playing
outside on a cold
winter’s day?
How
hot or cold
something is
Place one hand in
cold water, one
hand in “hot”
water for 1
minute. Then at
the same time put
both hands in the
luke warm water.
Describe what each
hand feels.
 What
do you consider to be “comfortable
temperatures”?
 Are you cold? Warm or just right?
 Room temperature is between 20°& 23°
 What are ways to standardize temperature
testing?

When would you use a devise and when would
you use your hand?

Why do some people feel cold when others feel warm?
 Example: You may feel cold in their classroom despite
the temperature being relatively high.
 Example: You may feel very warm in a house after
playing pond hockey on a cold winter day.

Reason:
 Energy always transfers from the warmer object to the
cooler object.

In this case, the warmer object is the water, and the cooler
object is the surrounding air. Since energy is transferred to the
air in the shower, the surrounding air becomes warmer. Once
you walk out of the shower, the new air you've entered is at a
lower temperature.
http://www.youtube.com/watch?v=6sUOMds_zmE
The
human body: 37°C
Boiling
point of
water:
100°C
Freezing
Point of
water: 0°C
p. 117 wild, weird, wonderful
p.119 Check your understanding
Terms assignment
p. 122
As the air
heats, the
liquids drops
and rises when
air is cooled.
http://www.youtube.com/watch?
v=_q5cUmA6zpE
Liquid rising
up the tube
shows the
temperature
is rising.
http://catalogue.museogalileo
.it/multimedia/FromThermosc
opeToThermometer.html
 Scales
are necessary for
temperatures to be accurate
and comparable.
 Early thermometers did not
have scales attached to them.
 Scales are necessary for
accuracy of measurement as
well as comparison of
temperatures.
3 commonly used scales are:
1. Fahrenheit
2. Celsius
3. Kelvin
Developed
by Gabriel
Fahrenheit
The first
to be
widely
used
Developed
by Anders
Celsius.
Based on
the freezing
and boiling
points of
water.
Developed
by
William Thomson
(Lord Kelvin)
Scale starts at the
coldest temperature
possible – absolute
zero (-273 ˚C)
Part
Function
Liquid
Colored alcohol that expands when
heated and contracts when cooled
Fine opening through which the
liquid moves
Bore
Thick Glass
Surrounds the bore
Thin Glass
Surrounds the bulb, allows for heat
to be transferred to the liquid
Scale
Numbers ranging from 0 C to 100 C
which the temperature is read from
Bulb
Storage space for the liquid, found at
base of thermometer
 Activity:

“The Laboratory Thermometer”
Need thermometers
1. The Liquid-in-glass
Thermometer
The lab thermometer contains
colored alcohol rather than
mercury for safety.
Made
of two
wires of different
metals.
A temperature
difference causes
a current to flow
Can
measure higher
temperatures than typical
thermometers such as in
kilns and diesel engines
http://
www.
youtu
be.co
m/wa
tch?v
=BB5
jjW1V
2DI
3. The Resistance
Thermometer (digital
thermometers)
Made
of two different
metals fused together.
These metals expand
and contract at
different rates causing
the strip to bend when
heated.
http://www.you
tube.com/watc
h?v=BQaUTIk
wojk
Heating and Cooling
a Bimetallic Strip
5. Infrared Thermometer
(thermogram)
 Converts infrared
radiation into colors
that can interpret a
temperature
difference.
Can be
used to
measure
heat loss in
your home
 Chapter
4 workbook