ENERGY AND MOTION Unit 1-section 1 Science- a process that uses observation and investigation to gain knowledge about events in nature.
Investigations scientists use: 1. Observing something that occurs and recording information. 2. setting up experiments that test the effect one thing has on another. 3. building a model that resembles something in the natural world and testing to see how that model acts.
The Scientific method 1. State the problem 2. gather information 3. form a hypothesis 4.test the hypothesis 5. analyze data 6. draw conclusion
Theory- an explanation of things or events Law- Tells you what will happen under certain conditions, but not how or why. A theory can be used to explain a law Dependent variable- value changes according to the changes in other variables Control- the standard that test results can be compared.
Constant- a factor that does not change when other variables change. Independent variable- the variable you change to see how it will affect the dependent variable. Bias- occurs when expectations change how experimental results are viewed
Standards of Measurement Measurement -The dimensions, capacity, or amount of something Standard- an exact quantity that people agree to use to compare measurements. Measurement systems include the International System of Units- SI
SI Base Units Quantity Measured Unit Symbol Length meterm Mass kilogram kg Time second s Electric Current ampere A Temperature Kelvin K Amount of substance mole mol Intensisy of light candela cd
Common SI prefixes Prefix symbol multiplying Factor Kilok1,000 Decid0.1 Centic0.01 Millim0.001 Microu Nanon
Measuring Distance Choosing the unit of length Measuring Volume Volume- the amount of space occupied by an object V= l x W x H Measuring Matter- Mass- a measurement of the quantity of matter in an object Density- the mass per unit volume of a material -Divide the objects mass by its volume derived units- a unit obtained by combining different SI units
Measuring Time and Temperature- Temperature is measure on the Celsius scale ( C ) Kelvin- the coldest possible Temperature is 0- also known as absolute zero Absolute zero is equal to degrees celsius Fahrenheit- the human body remains at 98.6 degrees Fahrenheit *The boiling point of water is 100 C and Freezing point 0 C *Kelvin scale- water freezes at 273 K and boils at 373K Ratio- a relationship in quantity, amount, or size. Text pg 834 questions 1-10
Communicating with graphs Visual displays- Graphs 1.Line graph- shows any relationship where the dependent variable changes due to a change in the independent variable. 2. Bar Graph-useful for comparing information collected by counting. 3. Circle graph- shows how a fixed property is broken down into parts. ** All three graphs are used to display data