Measurements and Calculations
Learning Log
This week in Chemistry, the main focus was Ch. 2 Measurements and Calculations. Quantity is something that has magnitude, size or amount. Units are helpful for describing a specific amount, like teaspoons, cups or grams. The SI (Le Systeme International d' Units) base units are length, mass, time, temperature and the amount of substance. They are measured in meters, kilograms, seconds, kelvin and moles. There are also converting units that change from unit to another like feet to inches, or kilograms to grams. Conversion factors are a ratio where the top units are equivalent to the bottom unit. An example would be that there is 5.4 kilograms equivalent to 5,400 grams. Besides the base units on the metric system, there is also giga (g), being the biggest and nano (n) being the smallest. A quantitative measure can be recorded as a number (quantity) while a qualitative does not involve a measured number, but a description. A variable is something that can change, the independent variable is the one being changed and the dependent variable is the one you measure. With measuring and calculating, there is accuracy and precision. The accuracy refers to the closeness of measurements to the correct or accepted value of quantity measured. Precision refers to the closeness of a set of measurements of the same quantity made in the same way. To find the percent error of something you would use the equation, value experimented-value accepted/value accepted X 100. Significant figures are digits that are known with certainty plus one final digit which is somewhat uncertain or is estimated. The rules for a digit being a significant figure is, 1. All non-zeros are significant, 2. Trailing zeros after a decimal are significant, and 3. All zeros between two significant zeros are significant. Scientific notation is a value that is expressed in two parts. The first factor consists of a number less than ten, but equal or greater than one. The second part consists of a power of ten.
Lab Abstract
This main purpose of the lab this week was to see how the measurements and recordings of objects are accurate or precise. From the measurements that were calculated in length, there were about 2-3 significant figures from the triple beam and a total of 6 combined overall. From comparing our measurements from the area in the classroom to a given one, the calculation had a percent error of -10.06% The accuracy from the lab measurements can make a big difference, even its off by a bit from the real measurement. Some improvements can take place by being more precise and rounding to nearest thousandth to see more of a difference.
Learning Log
This week in Chemistry, the main focus was Ch. 2 Measurements and Calculations. Quantity is something that has magnitude, size or amount. Units are helpful for describing a specific amount, like teaspoons, cups or grams. The SI (Le Systeme International d' Units) base units are length, mass, time, temperature and the amount of substance. They are measured in meters, kilograms, seconds, kelvin and moles. There are also converting units that change from unit to another like feet to inches, or kilograms to grams. Conversion factors are a ratio where the top units are equivalent to the bottom unit. An example would be that there is 5.4 kilograms equivalent to 5,400 grams. Besides the base units on the metric system, there is also giga (g), being the biggest and nano (n) being the smallest. A quantitative measure can be recorded as a number (quantity) while a qualitative does not involve a measured number, but a description. A variable is something that can change, the independent variable is the one being changed and the dependent variable is the one you measure. With measuring and calculating, there is accuracy and precision. The accuracy refers to the closeness of measurements to the correct or accepted value of quantity measured. Precision refers to the closeness of a set of measurements of the same quantity made in the same way. To find the percent error of something you would use the equation, value experimented-value accepted/value accepted X 100. Significant figures are digits that are known with certainty plus one final digit which is somewhat uncertain or is estimated. The rules for a digit being a significant figure is, 1. All non-zeros are significant, 2. Trailing zeros after a decimal are significant, and 3. All zeros between two significant zeros are significant. Scientific notation is a value that is expressed in two parts. The first factor consists of a number less than ten, but equal or greater than one. The second part consists of a power of ten.
Lab Abstract
This main purpose of the lab this week was to see how the measurements and recordings of objects are accurate or precise. From the measurements that were calculated in length, there were about 2-3 significant figures from the triple beam and a total of 6 combined overall. From comparing our measurements from the area in the classroom to a given one, the calculation had a percent error of -10.06% The accuracy from the lab measurements can make a big difference, even its off by a bit from the real measurement. Some improvements can take place by being more precise and rounding to nearest thousandth to see more of a difference.