Unit 1 Planner. 1.3 Error in Measurement - Taking Measurements. Be able to:

Transcription

1 Unit 1 Planner Name: 1.1 Number, Operation, and Measurement Basics Scientific Notation & Density Scientific Notation Be able to: Convert normal numbers to scientific notation and back. Describe when it might be valuable to use scientific notation. Use the scientific notation key on your calculator. Be able to compare the size of two numbers in scientific notation Density Be able to: Measure the density of solids and liquids. Measure volume by volume displacement or by geometry for regular solids. Draw particulate diagrams that give a subatomic description of relative density. Use the float/sink test to rank the densities of two substances. Solve for ml or g in a density calculation. 1.2 Dimensional Analysis Unit conversions Be able to: Convert a metric unit to another metric unit. Create metric conversion factors using a chart. Convert an English unit to another English unit. Interconvert metric and English units. 1.3 Error in Measurement - Taking Measurements Be able to: Use measuring equipment correctly by recording the correct number of digits. (6 ml and 6.0 ml are not the same thing!) Describe the difference between accuracy and precision. Label a measurement as more accurate or more precise than another measurement. Keywords: Random Error Systematic Error Accuracy Precision Scientific Notation Standard Notation Density Volume Mass Compactness Density Table Float Sink Unit

2 Tools of a Scientist Unit Date Topic 8/17 First Day of School-Introduction Activities, Syllabus 8/18 Equipment Lab 8/19 Taking Strides Measurement Lab 8/22 Taking Strides Measurement Lab, Penny Drop Activity 8/23 Accuracy and Precision Reading 8/24 Scientific Notation Notes and Practice 8/25 Scientific Notation Scavenger Hunt 8/26 Introduction to Density Notes, Density Equation Practice 8/29 Density Lab 8/30 Density Phet 8/31 Unit Quiz 9/1 Unit Conversions Tutorial 9/2 Unit Conversions Practice 9/5 Labor Day-NO SCHOOL 9/6 Unit Conversions WebAssign 9/7 Tools of a Scientist Unit Review 9/8 Tools of a Scientist Unit Test 8/17/16 Objective: Students will get to know each other, the teacher and the classroom. Warm-Up: Find a seat and introduce yourself to your table partner. 8/18/16 Objective: Students will use lab equipment to complete measurements. Warm-Up: None

3 8/19/16 Objective: Students will practice taking measurements and determine if they are accurate and precise. Warm-Up: Tools of a Chemist Equipment List Directions: Match the name of the tool with the correct description. 1. Erlenmeyer flask 2. Bunsen burner 3. Ring stand 4. Stirring rod 5. Hot plate 6. Balance 7. Beaker 8. Graduated cylinder 9. Scoopula 10. Micropipette 11. Spark lighter 12. Burette a. Often used as a reaction vessel (a contained place to mix reactants together) b. A long, skinny, graduated tube used to deliver and acid or base to a container c. A glass rod used to mix substances d. A device to which various clamps can be attached for laboratory purposes e. A piece of lab equipment that produces an open flame (from natural gas) f. A cone shaped container with a tapered, cylindrical opening. Its shape allows chemists to safely mix dangerous substances, like acids, without the risk of splashing g. A cylindrical container used to accurately determine the volume of liquids h. A flat-topped electrical device used to heat substances in the lab i. A round shaped spatula used to deliver solid reagents to reaction vessels j. A device used to accurately measure the mass of a substance k. A tool used to transfer small volumes of liquids l. A friction-activated lighter used to safely light a gas

4 Directions: Use the tool list on the previous page to determine the names of the following lab equipment

5 8/22/16 Objective: Students will determine if data is accurate, precise, or both. Warm-Up: 1. What is the SI unit of measurement for distance? 2. If everyone in your group walked the same distance, why were all of your distances different? 8/23/16 Objective: Students will determine if data is accurate, precise, or both. Warm-Up: Coin Diameter A gold coin has an accepted diameter of mm. Two students are asked to measure the diameter of four gold coins. Student A uses a simple plastic ruler. Student B uses a precision measuring tool called a micrometer. Student A plastic ruler 27.9 mm 28.0 mm 27.8 mm 28.1 mm Student B micrometer mm mm mm mm Which student s data is more accurate? Why? Which student s data is more precise? Why? Errors in Measurement As you read, in the margins, write a question mark for ideas or words that you are unsure about and a star for ideas that relate to you personally. Then, answer the questions at the end of each section. Random Errors There is no exact measurement. In the Investigate, when you used your stride length as the measuring tool, the distance of the hallway was different for many of the groups. If you tried to improve the measurement by using a meter stick, you found that there were still differences in the measurement. Even if you had used a tape measure, there would still have been differences in your measurements. Vocabulary Words: Box the following vocabulary words in the reading. Then, define them in YOUR OWN WORDS! random error: systematic error: Physicists know that all measuring tools produce random errors, or errors that cannot be corrected by calculating. It is the responsibility of the student scientist to record all the values of a measurement and recognize that the data will include random errors. Every time you measure the length of your desk, you might find that the measurement is different from a previous value by 0.1 cm. This difference could be in either direction (+ 0.1 cm). You can use a more precise ruler and that may decrease this random error or uncertainty to only 0.05 cm ( cm). However, the uncertainty can never be completely eliminated. accuracy: precision: Both the measuring tool and the person doing the measuring are responsible for the uncertainty. A meter stick that has only the centimeters noted would have a greater uncertainty than a meter stick that has the millimeters noted. A meter stick that has millimeters noted may still have a large uncertainty if the person using it is not very careful in aligning the meter stick with the length being measured.

6 In your measurement of the distance, you found different distributions of measurement. If you made histograms as shown below, of the length of a hallway using your stride (left figure), the meter stick (middle figure) or a tape measure (right figure), you can get a sense of the uncertainty in each type of measurement. The middle value is probably the "best guess" for the length of the room, but there will always be an uncertainty surrounding that value, as shown by the spread to the left and right of the middle value. 1. Underline the topic sentences or main ideas in the previous section. (You should not underline more than 5 words in a row!) 2. Summarize your main ideas from question 1 into one BIG IDEA of the section. (This should be no more than 2 sentences!) 3. What are some other examples of random errors? Systematic Errors There are also systematic errors. If you mistake a yardstick for a meter stick and report your measurement as 4 m, when in fact it is 4 yd, that is a systematic error. Every measurement you record with that yardstick will have this error. Systematic errors can be avoided or can be corrected by calculating. 1. Underline the topic sentences or main ideas in the previous section. (You should not underline more than 5 words in a row!) 2. Summarize your main ideas from question 1 into one BIG IDEA of the section. (This should be no more than 2 sentences!) 3. What are some other examples of systematic errors? Accuracy and Precision In shooting arrows at a target, you can have accuracy and precision by getting all the arrows in the bull s-eye (left figure). You can have precision, but not accuracy by having all the arrows miss the bull s-eye by the same amount (middle figure). You can also have accuracy, but without precision by having all the arrows surrounding the bull s-eye spread out over the area (right figure). Notice that here the average position is the bull s-eye (accuracy), but not one of the arrows actually hit the bull s eye (precision). People do not always need the same level of precision in their measurements. One decision you must make is how precise a measurement you want. For example, in motor racing, horse racing, or Olympic skiing, time has to be measured to the thousandths or tens-of-thousandths of a second. But when a painter estimates the time required to paint a customer s house, she or he may only need to know the time within a few hours. As you increase the need for precision, the measurement becomes more difficult (and often, more expensive to make).

7 1. Underline the topic sentences or main ideas in the previous section. (You should not underline more than 5 words in a row!) 2. Summarize your main ideas from question 1 into one BIG IDEA of the section. (This should be no more than 2 sentences!) SI System In physics, you will be using the International System of Units. The units are known as SI units, abbreviated from Le Système International d Unités. This is the system of units that is used by scientists. This system is based on the metric system. All units are related by some multiple of ten. There are seven base units that can be combined to measure all scientific properties. The base units that you will use in physics are shown in the table. You will also be using other units that are a combination of these base units. You will be introduced to these units when you need to use them. The best way to learn units is to use them frequently and correctly. It is not helpful to memorize lots of units. In this section, you measured the length of a distance in meters. The meter (m) is the base unit of length. Other units that you will use for measuring and describing length are the kilometer (km), centimeter (cm), and millimeter (mm). These three units are made up of the base unit meter and a prefix. An important feature of the metric system is that there is a single set of prefixes that relates larger and smaller units. All the prefixes are related by some power (multiple) of ten. Driving the Roads and United States Units of Measurement The United States does not use the metric system for everyday measurements. Distances along the road are measured in feet, yards, or miles. Speed limits are posted in miles per hour rather than kilometers per hour, as they are in many other countries. Below are some conversion factors for length in US measurements. 12 inches = 1 foot 3 feet = 1 yard 5280 feet = 1760 yards = 1 miles In this chapter, Driving the Roads, US measurements will be used to express distances and speeds with respect to driving and traffic. In the classroom, you will use SI units for measuring. Checking Up: 1. Explain the difference between systematic and random errors. 2. Explain why there will always be uncertainty in measurement.

8 3. What would the positions of arrows on a target need to be to illustrate measurements that are neither accurate nor precise? 8/24/16 Objective: Students will convert values from scientific to standard notation and vice versa. Warm-Up: A measurement was taken 3 times. The correct measurement was 68.1mL. Determine if the following sets of measurements are accurate, precise, both, or neither. a. 78.1mL, 43.9mL, 2mL b. 68.1mL, 68.2mL, 68.0mL c. 98.0mL, 98.2mL, 97.9mL d. 72.0mL, 60.3mL, 68.1mL What are they? o Standard and Scientific Notation Notes : a number written as a digit and nothing else. : a way to write numbers that makes it easier to write large and small numbers. Written in 2 parts: A digit between and (decimal point is after the first number) X 10 to a power Converting from Standard Notation to Scientific Notation: All you are doing is the! 1. Find the decimal. Mark it if necessary. 2. Mark where the decimal. 3. Count how many places the decimal has moved: this is your. a. Decimal left: exponent b. Decimal right: exponent 4. Write the number in this format: a X 10 b 5. Examples: 3, ,996

9 Convert from Scientific Notation to Standard Notation 1. Look at the exponent. This is you move the decimal. a. Positive number: move the decimal. b. Negative number: move the decimal. 2. Drop the X 10 b 3. Move the decimal and fill in the for. 4. Examples: X X X X X X 10 0 In the given pairs, which number is bigger? Hint: it may help to convert them from scientific notation to standard numbers to compare or 5.6 X X 10 5 or 6.45 X X 10-4 or 6 X X 10-5 or 5.43 X /25/16 Objective: Students will convert values from scientific to standard notation and vice versa. Warm-Up: 1. What does X 10 0 mean? 2. Change the following numbers from the given to standard scientific notation. a. 561 X 10 4 b X 10 3

10 8/26/16 Objective: Students will determine the density of an object using the equation, displacement, and the density table. Warm-Up: Vocabulary Match Density Density = Density is the ratio of mass to volume If the volume stays the same and the mass the density will o If the mass stays the same and the volume the density will Equation: Mass usually expressed in grams Volume usually expressed in cm 3 or liters, etc. Density is the measure of the of a material. How the atoms or molecules are to each other More than heaviness - density includes how much an object takes up!! All substances have density including liquids, solids, and gases. It is a physical property of the substance. How to solve for density using the density equation: Determining Density Regular Shapes- mass, then determine the volume by using a formula o Ex: Cones, cylinders, spheres, cubes, etc. Irregular Shapes- mass, then measure displacement of a liquid (usually water) by that irregularly shaped object. o o o o o Example: A 10.0 cm 3 sample of Copper has a mass of 89.6 g. What is the density of the Copper? Example: What is the weight of the ethanol that exactly fills a ml container? The density of ethanol is g/ml. Example: What volume of silver metal will weight exactly g? The density of silver is 10.5 g/cm 3.

11 Density Table o All known substances already have a calculated density. We put these numbers into a density table. o We assign water a density of 1.00 g/cm 3. o We can compare the density of other objects to determine if they will float or sink in water. If the density is than 1.00 g/cm 3, the object will in water. If the density is than 1.00 g/cm 3, the object will in water. 8/29/16 Objective: Students will determine the density of an object using the equation, displacement, and the density table. Warm-Up: 1. An object has a mass of 45g and a density of 0.955g/cm 3. What is the volume of the object? 2. An object has a density of 1.25g/mL and a volume of 12mL. What is the mass of the object? 8/30/16 Objective: Students will determine the density of an object using the equation, displacement, and the density table. Warm-Up: Vocabulary Scramble Word Scramble Definition Picture NITDSEY Amount of matter per unit of volume. LUVOEM SAMS MCCPOSATENS SDNYIET ALTEB The amount of space that a substance or object occupies. A rough measure of the number of atoms in a substance or object. How closely and neatly the atoms of a substance or object are. A chart that lists the known densities of objects. OTLAF NIKS Rest or move on or near the surface of a substance without sinking. To go below the surface of a liquid.

12 8/31/16 Objective: Students will determine the density of an object using the equation, displacement, and the density table. Warm-Up: Measuring Liquids What volume is indicated on each of these graduated cylinders? All measurements are in ml. Be sure to record the correct number of decimal places!

13 9/1/16 Objective: Students will convert between units using a conversion factor. Warm-Up: Using your conversion sheet Metric prefixes can be applied to any type of units. A prefix is prefix after all! Consider: The term anti is a prefix that means against or opposite Anti is used in lots of different words: Anti-war (against war) Antacid (opposite of acid) Anti-hero (not the typical hero) A metric prefix works the same way. Look at the prefix centi : Our conversion sheet says that 100 centi = 1 So: 100 centimeters = 1 meter 100 centiliters = 1 liter 100 centiwatts = 1 watt For each of these, use your conversion sheet to record the correct conversion factor: 1. How many milliliters are in liters? = 2. How many grams are in hectagrams? = 3. How many decimoles are in moles? = 4. How many meters are in kilometers? = 5. How many donuts are in centidonuts? = 6. How many dekavolts are in volts? =

14 9/2/16 Objective: Students will convert between units using a conversion factor. Warm-Up: Complete the following conversions. 1. Convert 4.75 centimeters to meters. 2. Convert 16.7 inches to feet. 3. Convert grams to pounds. 4. Convert 90 centuries to years. Steps: Multiple Unit Conversions We use multiple unit conversions when we don t have a conversion factor that gets us to the desired unit in step. Remember: conversion factors can be flipped! 1. Draw your. 2. Locate conversion factors that will get you to the desired unit. Write out in a chain what you are going to convert to. 3. Start with the unit that you have. Put this in the of your railroad tracks. 4. Write the first unit conversion with the unit you start with on the. (So they match!) Cancel the units. 5. Continue writing unit conversions with the unit of the conversion factor on the bottom in the next unit conversion until you get the desired unit. 6. the numbers on top and the numbers on bottom. 7. Include the in your answer. Example: How many ounces are in 167 grams? How many centimeters in 72 inches? How many yards are in 810 inches?

15 If I run 5 miles per hour, how many meters per second do I run? 9/6/16 Objective: Students will convert between units using a conversion factor. Warm-Up: Vocabulary Kahoot 9/7/16 Objective: Students will demonstrate their knowledge of introductory chemistry concepts on a unit review. Warm-Up: 1. How are you going to prepare for tomorrow s test? 2. What topics do you still need to study? 9/8/16 Objective: Students will demonstrate their knowledge of introductory chemistry concepts on a unit exam. Warm-Up: None