Chapter 1: Science Foundations of Science

1. What is Science?

• Science = A system of knowledge based on facts or principles

–Observation = gathered data that can be seen, heard, tasted, smelled, or touched

–Inference = a logical interpretation based on prior knowledge or experience

• Branches

–Social sciences

–Natural science (Biology, Physical science, Earth science)

2. Scientific theories and laws

• Science is an ongoing process; information improves and changes

• Theory = a tested, possible explanation of a natural event

–Simple and clear explanation

–Experiments must be repeatable

–Theory can be used to predict things

• Law = a summary of an observed natural event

3. The Scientific method

• Sci. Method = A series of logical steps to follow in order to solve problems– Observe

– Formulate a question

– Collect data

– Form a hypothesis = Proposed explanation of observed events

– Conduct experiment

– Collect data

– Draw conclusions

• Control = Condition in experiment that is kept the same

• Variable = Anything that can change in an experiment

Metric System

1. What is it?

• A system of measure based on water that converts in increments of 10s.

• 10 these = 1 those

10 those = 1 that

10 that = 1 them

• Advantage: easily converted and used across the world

• What are some of the things that we measure?– Height Volume– Length Weight

2. Metric Math • Prefixes

• Each prefix indicates ten times more than the previous• With each conversion of unit (change in prefix) you will

multiply by 10 or divide by 10– Moving right x 10– Moving left ÷ 10

King Henry Died By drinking chocolate milk

Kilo Hecto Deca Base deci centi milli

0.001 0.01 0.1 1 10 100 1000

• each time I multiply by 10 watch what happens to the decimal– 1 x 10 = 10.– 20 x 10 = 200.– 300 x 10 = 3000.

• the opposite happens when I divide by 10 – 3000 ÷ 10 = 300– 200 ÷ 10 = 20– 10 ÷ 10 = 1

The decimal slides one place with each x or ÷ by 10, so use the simple sliding method

• Steps of Metric conversion– 1. draw your metric line: KHDbdcm– 2. figure out which direction you will be moving– 3. determine how many times the decimal has to

slide between the units– 4. move the decimal in the given number– 5. Check to make sure the answer makes sense

• Example 1: 6 Km = _________________m– 1. KHDbdcm– 2. K.HDb.dcm (starting at kilometer and ending at

meter)… moving right– 3. decimal moves three spots– 4. 6 Km = 6000 m– 5. Yes, there are more meters in a kilometer

• Practice:– 526 m = 52600 cm– 8000 cm = 0.08 Km– 0.40 m = 400 mm– 0.0003 Km = 0.3 m

3. Scientific Notation

• Does anyone know what a googol is?– 1 followed by 100 zeros– Would you write it out?

Scientific notation = a method of writing or displaying large numbers in a simple format by sliding the decimal and accounting for the slides by multiplying by ten

• Number (1 to 9.9) x 10exponent

234 becomes 2.34

each slide of decimal = x 10 = exponent

• A googol is 1 x 10100

• Practice:– 2500 = 2.5 x 103

– 2503000 = 2.503 x 106

– 0.00002 = 2 x 10 -5

– .0002500030 = 2.50003 x 10-4

Accuracy vs. Precision

• The dictionary definitions of these two words do not clearly make the distinction as it is used in the science of measurement.

1. Accurate : "capable of providing a correct reading or measurement."

• In physical science it means 'correct'.

• A measurement is accurate if it correctly reflects the size of the thing being measured.

2.Precise means "exact, as in performance, execution, or amount. "

• In physical science it means "repeatable, reliable, getting the same measurement each time."

• We can never make a perfect measurement.

• The best we can do is to come as close as possible within the limitations of the measuring instruments.

• For example a metric ruler which has millimeter marks has a least count of 1 mm or 0.1 cm. and when properly used it can make more precise measurements than one with centimeter marks.

• It is "six point something": more than six but less than seven. With certainty we can say it is in the range of 6 to 7. Exactly where in that range is an estimate. We might guess it is 40% of the way, just less than halfway, between 6 and 7 or 6.4.

• It is clear that our estimate was close, but the measurement still does not align with a mark. Not only that, but we are having trouble reading the marks now because they are so fine. Now we can estimate with a higher precision that the measurement is 6.39, although you might say that it is 6.38 or even 6.40. Whatever it is, your best guess is 'correct' although it is not certain.

Density

Density is a physical property of matter

- the mass per unit volume of a substance

- how much “stuff” is in a certain “space”

- density remains the same for any volume of a pure substance

If something is known as being “light”… it probably has a small density

Common densities

Substance Density g/cm3

Water (l) 1.00

Water (s) – ice 0.92

Lead 11.3

Air (mixture) 0.00129

Density Math – density is calculated by dividing the object’s mass by its volume.

- density = mass = g = g

volume cm3 ml

Example 1: If a box has a volume of 3.0 cm3 and a mass of 9.0 g, what is its density?

Example 2: If a liquid has a volume of 200 cm3 and a mass of 800 g, what is its density?

Gasoline has a density of 0.7 g/mL. If your 4-wheeler uses 1,000 mL of gas doing donuts in the lawn, how much lighter is your ride (what mass of gas was used)?