Levels of Observation and SI• Observation: observing patterns in nature.

Can be elevated to a:

• Hypothesis: a tentative explanation. “If and then statement.”

Can be elevated to a:

• Theory: scientifically acceptable principle to explain phenomena. Ex. Plate Tectonics.

Can be elevated to a:

• Law: a concrete principle. Ex: Newton’s Laws of Motion.

Scientific Method

• State the problem

• Research the problem

• Form a hypothesis

• Test the hypothesis

• Draw conclusions from the data.

How to get a date using the Scientific Method…

1. State the problem:

“I need a date for this weekend.”

2. Research the problem…

• What will it take to solve my problem?

• To solve my problem, “I need to someone to take out this weekend.”

• Who can I take?

- Examine the possibilities.

- Eliminate poor choices.

- Consider likely choices.

3. Form a hypothesis

• A possible solution to my problem.

• The simplest solution is often the best solution.

“If I take (name of potential person), then we will have fun!”

4. Test the hypothesis

• Perform the task to see if the hypothesis works.

• “Ask (name of potential person) for a date.”

5. Draw conclusions from the data.• Data is the results of an experiment.

• In it’s simplest form, there are only two possibilities:

1.If your hypothesis was correct, you now have a date for this weekend. PROBLEM SOLVED!

2.If your hypothesis was incorrect, the experiment failed. DON’T GIVE UP! Do more research and continue process until solved.

- What was wrong with your original hypothesis?

- Did you make a poor selection?

- Form another hypothesis and test it.

Units of Measurement

Measurement• Most scientific studies and experiments use a standard

system of metric units called Le Système International d’Unités (International System of Units), or SI for short.

Methods of Scientists

• SI is a modern version of the metric system based on a decimal system that uses the number 10 as the base unit.

MeasurementLength

Methods of Scientists

– meter (m)– The meter is divided into 100 equal parts called centimeters

(cm). – The centimeter is divided into 10 equal parts called millimeters

(mm). – Long distances are measured in kilometers (km) which is 1,000

m.

Time– second (s)

MeasurementWeight and MassMethods of Scientists

– Weight is a measure of the gravitational force on an object.

– Weight varies with location depending on gravitational force.

– Weight is a force, and the SI unit for force is the newton (N). EX: 100 lbs on Earth = 16.6 lbs on the moon.

– – Mass is the amount of matter in

an object. The SI unit for mass is the gram (g).– The mass of an object, unlike

weight, does not change with an object’s position.

Methods of Scientists

Area– Area is the amount of surface included within a set of

boundaries and is expressed in square units of length, such as square meters (m2). A = length x width

Volume– The amount of space occupied by an object is the object’s

volume. V = length x width x height

• solid object = cubic meter (m3).

• liquid volumes = milliliters (mL3) or liters (L3).

Density

– Density is a measure of the amount of matter that occupies a given space.

– Density is calculated by dividing the mass of the matter by its volume.

KNOW this formula!!!

Density = Mass/Volume

Temperature

– Temperature is a measure of the average vibrations of the particles that make up a material.

– A mass made up of particles that vibrate quickly has a higher temperature than a mass whose particles vibrate more slowly.

– Temperature is measured in degrees with a thermometer.

• In science, temperature is often measured on the Celsius (C) scale. • In SI, temperature is measured on the Kelvin (K) scale.

Kelvin Scale• The Kelvin temperature scale (K) was developed by

Lord Kelvin in the mid 1800s. • The zero point of this scale is equivalent to -273.16 °C on the

Celsius scale. This zero point is considered the lowest possible temperature of anything in the universe.

• At the freezing point of water, the temperature of the Kelvin scale reads 273 K. At the boiling point of water, it reads 373 K.

• Whereas the Kelvin scale is widely used by scientists, the Celsius or Fahrenheit scales are used in daily life. These two scales are easier to understand than the large numbers of the Kelvin scale.

• Could you imagine waking up to your radio and hearing the DJ give a weather report like this: "It's going to be a beautiful day today with sunny skies and a balmy temperature of 297 K!" That's 24 °C or 75 °F.

Temperature conversions…• Convert Celsius to Kelvin: K = °C + 273

• Convert Celsius to Fahrenheit: °F = 9/5(°C) + 32

• Convert Fahrenheit to Celsius: °C = (°F − 32) · 5/9

Convert to a) Fahrenheit and b) Kelvin:

1) 22° C

2) 12° C

3) 0° C

4) 100 ° C

Answer: 1.8(22) =39.6 +32 = 71.6° F

Answer: 1.8(12) =39.6 +32 = 53.6° F

Answer: 1.8(0) =0 +32 = 32° F (Freezing point)

Answer: 1.8(100) =0 +32 = 212° F (Boiling Point)

Convert Fahrenheit to Celsius: °C = (°F − 32) · 5/9

Convert F to C:

1) 77° F

2) 87° F

3) 67° F

4) 212° F

5) 32° F

Answer: (77 - 32) = 45 · 5/9 = 25° C

Answer: (87 - 32) = 55 · 5/9 = 30.8° C

Answer: (67 - 32) = 35 · 5/9 = 19.6° C

Answer: (212 - 32) = 180 · 5/9 = 100.8° C

Answer: (32 - 32) = 0 · 5/9 = 0° C

Scientific Notation• To express numbers that are very large or small, scientists

use a type of shorthand called scientific notation to express the number as a multiplier and a power of 10.

– In scientific notation, a number is expressed as a value between 1 and 10 multiplied by a power of 10.

– The power of 10 is the number of places the decimal point must be shifted so that only a single digit remains either to the left or right of the decimal point.

5 974 200 000 000 000 000 000 000 =

0.0000000001 =

For example:90 000 000 000 =

Scientific Notation– If the decimal point must be shifted to the left, the exponent of

10 is positive.– If the decimal point in a number must be shifted to the right,

then the exponent of 10 is negative.

9 X 1010

5.9742 X 1024

1 X 10-10

Science Research Investigation Project

Parts of the Experimental Design

• Title: A statement describing the cause and effect.

• Hypothesis: a tentative explanation. “If and then statement.”

• If the (independent variable) is (describe how it will be changed), then the (dependent variable) will (describe the effect).

• Independent Variable (IV): This is the variable which is changed or manipulated.

• Dependent Variable (DV): This is the result of the change or manipulation. It is what is measured.

• Levels of the Independent Variable: different variations of testing that are done on the subject.

• Number of trials: This is the number of times the experiment was done. Usually, the more trials, the greater the validity.

Parts of an experiment

• Control: a comparison group against the standard.

• Constants (C): details of the experiment which are

kept the same.

What is the Scientific Method (21 min)

Ten seeds were planted in each of 5 pots found around the house that contained 500g of “Peat’s Potting Soil.” The pots were given the following amounts of distilled water each day for 40 days: Pot 1, 50 mL; Pot 2, 100 mL; Pot 3, 150 mL; Pot 4, 200 mL; Pot 5, 250 mL. Because Pot 3 received the recommended amount of water, it was used as a control. The height of each plant was measured at the end of the experiment.

For the following sample lab scenario, identify:

1.Title2.Hypothesis3.Independent Variable4.Dependent Variable5.Control6.Constants

What is the Independent Variable?

Title

Hypothesis

IV: Amount of distilled water (mL)

control

DV:

C:

What is the Dependent Variable?

Title

Hypothesis

IV: Amount of distilled water (mL)

control

DV: Height of the plants

C:

Title Hypothesis IV: Amount of distilled water (mL) control DV: Height of the plants C:

What is the title?

Title The Effect of the Amount of Distilled Water on the Height of the Plants Hypothesis IV: Amount of distilled water (mL) control DV: Height of the plants C:

What is the hypothesis?

Title The Effect of the Amount of Distilled Water on the Height of the Plants Hypothesis If the amount of distilled water is increased, then the height of the plants will increase. IV: Amount of distilled water (mL) control DV: Height of the plants C:

What are the levels of the IV?

Title The Effect of the Amount of Distilled Water on the Height of the Plant Hypothesis If the amount of distilled water is increased, then the height of the plant will increase. IV: Amount of Distilled Water (mL) 50 100 150 200 250 DV: Height of the plants C:

How many trials were done?

Title The Effect of the Amount on the Height of the Plant Hypothesis If the amount of distilled water is increased, then the height of the plant will increase. IV: Amount of Distilled Water (mL) 50 100 150 200 250 10 10 10 10 10 DV: Height of the plants C:

Is there a control?

Title The Effect of the Amount of Distilled Water on the Height of the Plant Hypothesis If the amount of distilled water is increased, then the height of the plant will increase. IV: Amount of Distilled Water (mL) 50 100 150 200 250 control 10 10 10 10 10 DV: Height of the plants C:

What was kept constant?

Title The Effect of the Amount of Distilled Water on the Height of the Plant

Hypothesis If the amount of distilled water is increased, then the height of theplant will increase.

IV: Amount of Distilled Water (mL)

50 100 150 200 250

control 10 10 10 10 10

DV: Height of the plants

C: same type and amount of soil; same type of water

Are there any design flaws?

Hypothesis If the amount of distilled water is increased, then the height of theplant will increase.

IV: Amount of Distilled Water (mL)

50 100 150 200 250

control 10 10 10 10 10

DV: Height of the plants

C: same type and amount of soil; same type of water

Design Flaws: poorly defined constants infrequency of measurement

Title The Effect of the Amount of Distilled Water on the Height of the Plant

Hypothesis If the amount of distilled water is increased, then the height of theplant will increase.

IV: Amount of Distilled Water (mL)

50 100 150 200 250

control 10 10 10 10 10

DV: Height of the plants

C: same type and amount of soil; same type of water

Design Flaws: poorly defined constants infrequency of measurement