Life Sci Metrics Length-Vol

Report
The ABC’s of Science
Intro to Life Science
Measurement
Metric System Part 1:
Length
Volume
Science is all around us
• Botany: the study of plants, uses PS to
explain how plants use carbon dioxide
(CO2) and water (H2O)to make food
Science is all around us
• Geology: explain earthquake waves and rock
composition
• Oceanography: chemistry of ocean water
• Ecology: the nitrogen cycle and the transfer of
energy between organisms in a food chain
• Biology: how the heart pumps blood, how the
eyes & ears work and how the brain sends
electrical impulses throughout the body.
What are the ABC’s of Science?
A. The Metric System
B. Safety Rules
C. The Scientific Method
--> We will be “reviewing” all of the above… pay
attention, you will be tested on it!
Mini-Contest
• Which group can measure the length of the
room the BEST?
• In your group, plan (quietly and secretly)
HOW you are going to measure the room.
You have 3.5 minutes to plan
• You may use any of the measuring tools on
the counter.
• Now, grab your tools and MEASURE (you
have 4.5 minutes)
Mini-Contest
• Write down our answer on a sticky
note.
• Let’s see who got the answer.
• Answer: the room is _________
long.
• Did everyone get the same answer?
• Why not?
It all depends on the foot!
• Numbers and units are used
to make measurements.
• The distance from your
desk to my desk could be
25 shoe lengths or 30 shoe
lengths.
• It depends on how big the
shoe is.
• Think of Shaq’s foot versus
Mini-Me.
It all depends on the foot!
• You can see that to use practical measurements, a
measurement standard HAS to be used.
• In other words, everyone has to use the SAME
system or units.
• Otherwise, it just gets confusing.
Let’s talk Metric
• A standard is a fixed quantity used by
everyone when measuring.
• Here in America we use an English system:
foot, yard, and mile.
• However, MOST people use another system
called the International System of Units or
SI (which stands for Système Internationale
d’Unités)
• This is the modern form of the metric system.
Measurement
• By using this system ALL scientists can
understand each others measurements.
• If I conducted an experiment here in
America, even someone in Zimbabwe would
be able to understand my measurements.
• And, everything is done in multiples of 10,
so changing from one unit to another is
easier than with English units.
Break it down
•
•
•
•
•
OK, let’s get this as simple as we can.
We are going to look at all of our metric
measurement units as two-part words.
The first part is the PREFIX.
The second part is the type of UNIT.
So --> PREFIX - UNIT
Part 1: the PREFIX
•Here are some important prefixes:
You need to memorize these
Prefix
Symbol
Meaning
kilocentimillimicro-
k
c
m
µ
1000 (1 thousand)
0.01 (1 one-hundredth)
0.001 (1 one-thousandth)
0.000001 (1 one-millionth)
Part 2: the UNIT
•Here are some important UNITs, and you
need to memorize these too.
What are we
measuring?
Length
Volume
Mass
Temperature
Unit
meter
liter
gram
kelvin
Break it down yo’self!
• One kilometer is equal to ____ meters.
– kilo - meter
• prefix = kilo or 1000
• meter = unit measuring distance
• Therefore: 1 kilometer = 1000 meters.
• 5 kilometers would be:
– 5 x 1000 meters = 5,000 meters
• Always remember to break it down!
I still don’t get it.
• Here’s another way to go from one unit to another; just
remember:
• King Henry Died of Drinking Chocolate Milk Mmmmmm.
• King Henry Died of Drinking Chocolate Milk Mmmm
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• To convert to a larger unit, move the decimal
place to the left (divide)
• To convert to a smaller unit, move the decimal
place to the right (multiply)
Let’s Practice
1.
10 grams = _____ kilograms
•
•
Move the decimal three places to the left (divide)
.01kg
2. 56 meters = _____ centimeters
•
•
Move the decimal two places to the right (multiply)
5,600 cm
3. 876 centimeters = ____ kilometers
•
•
Move the decimal five places to the left (divide)
.00876 km
Measuring Length
Let’s talk Length
• The meter (m) is the SI unit of length.
• A meter is about the distance from a
doorknob to the floor.
• A driver golf club is also about a meter
in length.
• The meter is divided into 100 equal
parts called centimeters (cm).
• There are 100 centimeters in a meter:
– 100cm = 1 m
Measuring Length
• An even smaller unit is a millimeter (mm).
• The prefix milli- means 1/1000, so…
– 1000 mm = 1 m
– 10 mm = 1 cm
• Long distances are measured in kilometers
(km)
• Note: here is the US, we measure speed by
miles per hour, or mph. In most other
countries, they measure in kilometers per
hour.
You try it!
4. Name 3 things that are about one meter
long
5. Name 3 things that are measured in
centimeters
6. Name 3 things that are small enough to be
measured in millimeters
Answers:
4. Meters: golf club, bath towels
5. Centimeters: your little fingernail, the
distance between the lines on standard
notebook paper, the width of a large paper
clip
6. Millimeters: wire diameter, book thickness,
tape width, camera film
Let’s talk Volume
• Have you ever heard someone
say “this shampoo gives my hair
a lot of volume!!!”
• What does that mean?
• Volume means to take up space.
• Or, volume is the amount of
space occupied by an object.
• So if someone’s hair has a lot of
volume, that means it is full.
• It takes up a lot of space.
Measuring Volume
Measuring Volume of Solid
Rectangular Objects
• For solid rectangular
objects, the volume is the
length x width x height.
• V = l x w x h
• A cubic meter (m3) is a
unit of volume.
• A cubic meter is a very
large unit - it contains
1,000,000 cubic
centimeters.
You try it!
7. What is the volume of this
solid?
• V=lxwxh
• V = 4cm x 1cm x 2cm
• V = 8 cm3
8. What is the volume of this
solid?
• V = 3cm x 3cm x 3cm
• V = 27 cm3
Measuring Volume of
Liquid Objects
• For liquid objects, we use graduated
cylinders to measure the volume.
• In cooking, we may also use
measuring cups, teaspoons or
tablespoons.
• The level of a liquid in a graduated
cylinder shows the volume of the
liquid.
• A liter (L) is a unit that is usually
used to express volume
• A soft drink bottle is a 2-liter
bottle.
Measuring Volume
• For smaller volume measurements, we also
use:
– milliliter (ml)
– cubic centimeter (cm3).
• One liter contains 1000 milliliters or 1000
cubic centimeters.
• 1L = 1000ml = 1000 cm3
• 1mL = 1 cm3
Accuracy is Everything
• To read the
volume of the
liquid, note the
level at the
bottom of the
curve.
• We call this the
meniscus.
You try it!
9. What is the volume in ml?
– 73 ml
10. What is the volume in ml?
– 21.5 ml
Measuring Volume of Solid
Irregular Objects
• So, how would I measure the volume of an
irregular object such as a piece of clay?
• I can’t measure the sides and I can’t use a
measuring cup.
• But I CAN still use a graduated cylinder.
• Simply submerge the object in the graduated
cylinder and record the difference in water
level.
• We call this measuring volume by displacement.
• You will practice it during the lab today.
Measuring Volume of Solid
Irregular Objects

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