HB 1.A.4 through HB 1.A.8

Precision and Accuracy Precision- measure of the degree to which measurements made in the same way agree with one another. How repeatable are your measurements. The more repeatable, the more precise. Accuracy- of a result is the degree to which the experimental value agrees with the true or accepted value How close a measurement is to an actual or accepted value. The closer it is to the accepted or actual value, the more accurate.

What this means for an experiment High degree of precision but poor accuracy Means the same error is involved in repeated trials of an experiment. High degree of accuracy and poor precision Means the measurements reached the accepted value once but it was not repeated. You should try to be accurate and precise in every experiment But it is impossible to be completely accurate using the naked eye. The more decimals in the recorded measurement, the greater the precision of the instrument. An instrument read to the hundredths place is more precise than an instrument that reads to the tenths place. The last digit read should be estimated on any piece of equipment.

Graphing Why do it? Steps to graph Organize data Provide an easy way to explain data without the person reading the report. Steps to graph Make a table Independent variable on the left and dependent variable on the right Graph the organized data Independent variable on the “X” axis and dependent variable on the “Y” axis. Choose scales for X and Y axis 2 data points more than is needed on the vertical Horizontal should be long enough for all data points to fit Intervals should be in equal increments Label each axis with name of the variable and units of measure Title the graph

Examples of Graphs

What graph should I use? Different relationships between different independent and dependent variables mean you should use different graphs. But how do you know which one to use? Line graph use with data that is collected all at the same time. Ex. Any variable over time Bar graph use with data collected with different categories. Circle graph use with data that shows a relationship to parts of a whole. Ex. percentage

Stepping Up to SI In SI different units measure different things just like in English measurements Meters = length Seconds = time Liters = volume Kelvin = heat Gram = mass Ohms =current The ones above are base units. We add a prefix to the base to make the base unit smaller or bigger. The prefixes you need to know are: Kilo- =1000 B Deci- = .1 Hecto- = 100 A Centi- = .01 Deka- = 10 S Milli- = .001 E

Stepping Up to SI There are two ways to convert from one to the other. Both are fairly easy since they are all in increments of 10. Conversion factors Stairsteps

Metric Stairs Start at the step your unit is on and move the number of steps to get to the unit you are changing to. For every stair you move up move the decimal point to the left. For every stair you move down move the decimal point to the right.

Science and Technology Science is a process of inquiry that searches for relationships that explain and predict things in our world. Technology is the application of scientific discoveries to meet needs and goals of humans through the development of products and processes Science affects technology Science is applied to technology to make products and processes that meet the needs of mankind In science the scientific method is used In technology the technological design process is: Identify need or problem Solution designed to meet it Product is developed and tested Results analyzed to determine how well it solved the problem

Comparison of Science and Technology