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SCIENTIFIC MEASUREMENTS. CHAPTER 2. UNIT OBJECTIVES: Students will: Review metric measurements Demonstrate proper metric measurement techniques Investigate ingredient content and affect of ingredients on chewing gum. USING MEASUREMENTS
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SCIENTIFIC MEASUREMENTS CHAPTER 2
UNIT OBJECTIVES: Students will: • Review metric measurements • Demonstrate proper metric measurement techniques • Investigate ingredient content and affect of ingredients on chewing gum
USING MEASUREMENTS Accurate measurements must be taken to have a successful experiment. The student must identify a system of measurements to be used. Metric versus Standard Determine what you are trying to measure. Mass – the amount of matter in an object. Length – distance between two points Volume – amount of space occupied by an object Determine which method will give you the most accurate results.
MEASUREMENT SYSTEMS • System International, SI units, Metric system • STANDARD SYSTEM
HOW TO MEASURE MASS • Mass-the amount of matter in an object • Will often have to use a container • (Use something light weight) • Use digital scales • Must subtract the weight of the container (taring) • or zeroing the scale. • Mass the container, then mass the substance and the container. Subtract the mass of the container to find out the mass of the substance.
How to Measure Length • Length-the distance between two points Use a ruler • Place an object between two vertical surfaces, notate the location of the ends of the object and measure between the end points.
How to Measure Volume • Volume-the amount of space occupied by an object • Cube (l x w x h) • Liquids measured by volume (ounces, liters) • Measure liquids in clear containers with graduated scales • Measure to the bottom of the meniscus (the curve at the surface of the liquid)
How to Measure Time You may use one of the following: • a second hand timer on a watch • the clock • The stove minute timer • or ask the teacher to use your cell phone.
How to Measure Temperature • SI unit (metric) is Celsius notated ‘C, (Most recipes use Fahrenheit degrees, ‘F.) (Stoves measure in Fahrenheit degrees, ‘F.) • Celsius – 0’C is freezing and 100’C is boiling • Fahrenheit – 32’F is freezing and 212’F is the boiling point • C’ = (5/9) x (degree F’ – 32)
Experiment 2a - balancing chewing gum OBJECTIVE: Scientific procedures require accuracy and consistency. The student will : become familiar with the electronic balance (scale) and how to use it. EQUIPMENT: Electronic balance (scale) 1- stick regular chewing gum per lab member 1-stick sugar-free chewing gum per lab member
PRE-LAB and POST LAB Copy each of the questions that follow and prepare the charts as directed. Read each question and in the left column predict the results. In the right column, record your data and findings. PROCEDURE: 1. Become familiar with the electronic scale 2. Use the gum wrapper as weighing paper. Tare (weigh) the gum wrapper. 3. Mass the regular gum. Record the mass in the data table (see example below).
4. Chew the gum for TWO minutes. (Watch the clock closely for accuracy.) 5. Place the chewed gum on the weighing paper and mass it. Record the mass in your data table. 6. Subtract the mass of the chewed gum from the original mass of the gum and record the difference. 7. Repeat the above procedures with the sugar-free gum. Record all your data in the chart. QUESTIONS: 1. Which type of gum will have a greater loss of mass after chewing?
Will there be a difference in texture between the two types of gum? If so, describe it? 3. What substance causes the loss of mass and difference of texture during chewing? Given that sugar has 4 calories per gram, how many calories would you estimate are in a stick of gum?
How does your answer compare to the nutrition label on the gum package? 6. What substance might cause the gain or loss of mass after chewing?
LAB DATA: Tare of the gum wrapper:
CONCLUSION • An interpretation of the data using graphs, charts, or paragraphs. • Explains the data collected. • Uses words like: ‘since’, ‘because’, ‘the reason I know this is . . .’ • Points out supporting or opposing facts. • May explain problems encountered during the experiment.
GUM EXPERIMENT CONCLUSION • Make a one or two sentence statement relating your predictions, your facts and your conclusions from the experiment.