Scientific MethodMetrics

Do Now: Make a list of some units you know. Try and classify them as metric or the English system.

Prefix Symbol Meaning Numerical Value

Giga- G 109 1,000,000,000

Mega- M 106 1,000,000

Kilo- k 103 1,000

Hecto- h 102 100

Deka da 101 10

BASE g, l, m 100 1

Deci- d 10-1 .1

Centi- c 10-2 .01

Milli- m 10-3 .001

Micro- m 10-6 .000001

Nano- n 10-9 .000000001

Measurement Base Unit

Length

Mass

Volume

Temperature

Time

Measuring always involves some estimation

Certain Digits: A digit that represents a mark on a scale or a non-blinking number on a display.

Uncertain Digits: A digit that represents the space between the marks on a scale or a blinking number on a display.

24.62 what is certain?what is uncertain?

The Kelvin Temperature Scale

Absolute Zero:The point at which all motion of particles stops (no more kinetic energy)

Can we ever reach absolute zero?

oC K

0 oC

450 K

- 40 oC

225 K

K = oC + 273

oF oC K

What is the freezing point of water?

What is the boiling point of water?

Chemistry:• the study of:

the composition, structure, and

properties of matter and the

changes it undergoes

Scientific Method • Logical approach to solving problems

1. Observation2. Problem3. Hypothesis4. Experiment

- Data- Analysis

5. Conclusion

What is a Hypothesis?

an educated guess

Observations

• Qualitative: quality, non-numeric terms

• Quantitative: quantity, numerical description

weather height weight speed

• System: specific portion of the experiment that has been selected for study

In an experiment…

Constant: experimental conditions that do not change

Control: experimental condition that is used as a standard for comparison

Variable: experimental condition that does change

Complete Example problem on Notesheet

Scientific Notation

602,200,000,000,000,000,000,000

6.022 x 1023

0.0000000000000000000000199

1.99 x 10-23

Some numbers are very large or very small, so a short hand notation is needed!

Too large:

Too small:

N x 10n

N is a number between 1 and 10

n is a positive or negative integer

if n is a negative number, the full number is a small decimal

if n is a positive number, the full number is a large number

3.69 x 10-4 ________________1.245 x 105 ________________

General Notation:

Density: ratio of mass to volume “how much stuff is packed into a given area”

Density of Liquids:Density gradients are made by layering substances of varying densitiesGreater density is on the __________Lower density is on the __________

Objects > sinkObjects < float

Solids have a greater density than liquids.

Solid:

Liquid:

So, when water freezes… ice sinks. Right?

WATER IS A SPECIAL CASE!!!The density of ice is less than

water!

This allows fish to survive at the bottom of the lake in winter!

D = m V

m

D V

A sample of aluminum metal has a mass of 8.4 g. The volume of the sample is 3.1 cm3. Calculate the density of aluminum.

Given: Unknown:

Solution:

Answer:

m

D V

A piece of iron has a density of 5.8 g/mL. It displaces a volume of 23.6 mL.What is the mass of the piece of iron?

Given: Unknown:

Solution:

Answer:

m

D V