Scientific Method and Units of Measure

Do Now Write down the steps a scientist might use to solve a problem – this is called the scientific method. Hint – there are 6 steps

Steps to the Scientific Method Organized Common Sense Observing and stating the problem Forming a hypothesis Testing the hypothesis Recording and analyzing the data Forming a conclusion Replicating the work

Scientific Method Video YouTube - Chemistry Music Video 1: The Scientific Method 3 minutes

1. Observing and stating the problem Observation – leaves change color in autumn Why????

2. Forming a Hypothesis Hypothesis – possible explanation, preliminary conclusion or even a guess about some event in nature It gets cold and that causes the leaves to change color

3. Testing the Hypothesis Perform an experiment - In July, take a small tree growing in a pot and place it in a growth chamber set to autumn temperature levels. - If our hypothesis is right, the leaves should change color. - If the leaves do change color, would we know if it was definitely due to the temperature?

3. Testing the Hypothesis Not really!!! There are factors other than temperature that are different between our tree in the growth chamber and a tree growing outside. Our tree is growing in a small pot. Our light is not natural light. Etcetera

Variable A variable is the factor that is isolated and tested in an experiment. In a good experiment, all factors other than the variable should be kept the same. Our variable is the temperature in the growth chamber.

Types of Variables Variables are things that may be expected to change during the course of the experiment. The investigator deliberately changes the independent variable. (CAUSE) He or she measures the dependent variable (EFFECT) to learn the effect of changing the independent variable. To eliminate the effect of anything else that might influence the dependent variable, the investigator tries to keep standardized variables constant.  

Control We need a control, which is the part of an experiment that does not contain the variable (temperature) Grow a second tree in a pot an place it in a growth chamber also. But, set the temperature in this chamber to normal summer temperatures. Now, if the leaves change color we can be more sure it was due to the colder temperature.

4. Recording and Analyzing Data As you perform the experiment you must collect data by recording observations and information In our experiment, we could count the number of leaves that changed color and the time it took for them to do so. Then you must analyze the data by putting it in tables and graphs

Forming a conclusion Yahoo Forming a conclusion Yahoo! Video Detail for Why do leaves change color in the fall? Now we have to decide if our hypothesis is true. We look at our data – does it support our hypothesis? In our experiment, if only the leaves on the tree in the colder chamber change color, we may decide that we confirmed our hypothesis. If the leaves of neither or the leaves of both trees change color, we may reject our hypothesis.

6. Replicating the work The original researcher must be able to reproduce the experimental results. Other researchers should also be able to reproduce the experiment.

Hypothesis and theories Theory – when a hypothesis is tested and confirmed often enough that it is unlikely to be disproved by future tests Powerful time tested concept that makes useful and dependable predictions about the natural world

Activity – Identifying Variables Read each scenario and figure out the Independent variable Dependent variable Standardizing variables Control Group ***Each student should hand in a completed copy of this work!

Graphing A graph is a diagram representing a system of connections or interrelations among two or more things by a number of distinctive dots, lines, bars, etc Graphs have an: X axis (horizontal) – represents your independent variable Y axis (vertical) – represents your dependent variable It is a great way to present scientific data because it is easier for people to understand than a bunch of numbers

Graphing Activity Complete the graphing activity “Scientific Method – Thumb Wrestling” Measure and record your thumb length and circumference and your wrist circumference on your lab sheet and on the board Pair off with a same sex student Play 1 round of thumb wrestling Winner moves on to play another winner, loser sits out Play until there is only 1 female and one male winner left Winners record data on board Complete experimental data, analysis and conclusion and hand in.

Homework Complete 2 review sheets Study for test

A Universal Language – The Metric System YouTube - Metric & Standard Measurement Systems

Metric System Science works best when scientists read each other’s papers, check each other’s experiments, and argue about what results mean. To do this they need a universal system of measurement to present their findings. Scientists use the metric system of length, volume, mass, and temperature when describing experiments and data.

Metric System Decimal system based on certain standards and scaled on multiples of 10: Kilo – 1000 Basic Unit Centi – 1/100 Milli – 1/1000 Micro – 1/1,000,000

Metric System Do you know the common metric units?? Length? Volume? Mass? Temperature?

Length Meter – basic unit of length in the metric system Equivalent to 39.4 inches (a little longer than a yard) Kilometer (1000 meters) Meter Centimeter (1/100 of a meter) Millimeter (1/1000 of a meter)

Volume Volume - amount of space an object takes up Cubic Meter – basic unit of volume for solids in the metric system Liter – basic unit of volume for liquids in the metric system Kiloliter (1000 liters) Liter Centiliter (1/100 of a liter) Milliliter (1/1000 of a liter)

Mass and Weight Mass – measure of the amount of matter in an object Weight – a measure of the pull of gravity on the mass Weight can change – mass never changes (space) Gram – basic unit of mass in the metric system Kilogram (1000 grams) Gram Centigram (1/100 of a gram) Milligram (1/1000 of a gram)

Temperature Celsius Scale – metric temperature scale Water freezes at 0oC Boils at 100oC Each Celsius degree is 1/100 of the range between freezing and boiling Normal Human Body Temperature is 37oC Room Temperature is approximately 21oC

Metric System Activity Get into your working groups Complete the conversion worksheet ***Each student should place a completed copy of this work in their ISNB!

Metric Scale Measurement Lab