The World of Physical Science Chapter 1 The World of Physical Science

What is Science? Science is a process of gathering knowledge about the natural world. What are some of the different types of sciences that a person can study?

Science Life Earth and Space Physical Biology Astronomy Physics Chemistry Anatomy Meteorology

What is Physical Science? Physical science is the study of matter and energy. Matter is made up of atoms and has both a mass and volume. Energy is the ability to do work. The branches of physical science Chemistry Physics

Chemistry Chemistry is the study of all forms of matter, including how matter interacts with other matter. Chemistry looks at the structure and properties of matter.

Physics Physics looks at energy and how that energy affects matter. Motion, force, gravity, electricity, light, and heat are parts of physics.

Many sciences use chemistry and physics (the physical sciences) Meteorology – the study of weather uses physics to understand pressure differences in the atmosphere Geology – the study of the structure of the earth uses chemistry and physics to understand heat, force and chemical composition of rocks Biology- the study of living things uses chemistry and physics to understand the chemical reactions in plants and animals and physics to study how living things move.

What are the “steps” of the Scientific Method? The scientific method are the ways in which scientists answer questions and solve problems. Observation Ask a question Form a hypothesis Test the hypothesis Analyze results Draw conclusions Communicate results

Steps of the Scientific Method 1) Observation The use of the senses to gather information. Qualitative – color, odor, taste, etc. Quantitative – measurements. Instruments used: Rulers, balances, stopwatches, etc.

Steps of the Scientific Method 2) Ask a question 3) Hypothesis An explanation that is based on prior scientific research or observations and can be tested. If – then statement.

Steps of the Scientific Method 4) Testing the Hypothesis – Experiment A controlled experiment compares the results from a control group with the results from the experimental groups. The groups are exactly the same except for one factor. That factor is the variable. Independent variable is the variable you change. Ex. Time Dependent variable changes in response to the independent variable. Ex. Distance

Steps of the Scientific Method 5) Collect, Record, and Analyze Data Data is the information gathered through your experiment. All information needs to be recorded in a notebook, in a data table or other recording devices. Organizing material makes analyzing the data easier.

Steps of the Scientific Method 6) At the end of the investigation, you draw your conclusion. Accept or reject Change your hypothesis and retest. 7) Communicate results How can you do that?

A gardener decided he wanted to try a fertilizer for his tomato plants A gardener decided he wanted to try a fertilizer for his tomato plants. He put fertilizer is 20 plants and called them group A . He just put regular soil into 20 plants and called them group B. Both groups received the same amount of sun light exposure, water, and were exposed to the same temperatures. He found that plants in group A produced an average of 25 kgs of tomatoes where plants in group B produced an average of 15 kgs of tomatoes.   State the hypothesis of the experiment: State the independent variable, the one you changed: State the dependent variable, the one that changed because of the experiment: Which was the control group? What variables were controlled? 6. State a conclusion for the above experiment:

Theory vs. Law A theory is an explanation for many hypotheses and observations. Supported many times. Can predict future results. Can not be proven 100% Examples Big Bang Theory Einstein’s Theory of Relativity A law is a summary of many experimental results and observations. Laws are always true and do not change. Examples Newton’s Laws of Gravity Conservation of Mass

Measurements Length Volume Mass Temperature Density Time Meters Liters Kilogram Temperature Kelvin or Celcius Density g/cm3 Time seconds

Metric Measurements Prefixes Symbol Factor of Base Unit kilo- K 1,000 hecto- H 100 deka- D 10 BASE m, L, g, s Meter, liter, gram, second deci- d 0.1 centi- c 0.01 milli- m 0.001

Metric Conversions K H D __ d c m 1378 millimeters = ________ dekameters 45 centimeters = ________ decimeters 4 liters = ________ hectoliters 5 kilograms = ________ grams

Scientific Notation 12345 = 1.2345 x 104 0.00456 = 4.56 x 10-3 A way to express very small or very large numbers Example: 12345 = 1.2345 x 104 0.00456 = 4.56 x 10-3 Exponent – the # of times the decimal was moved (+) to the left (-) to the right Coefficient – must be between 1 and 9 Base

Scientific Notation 56934 = 1280 = 0.0345 = 0.0000037 =

Scientific Notation Reverse it! (+) right (-) left 2.347 x 10-3 =