Measurement and Data Collection Pre-AP Biology
Bellwork You are making a 10% gelatin solution by adding 10 g of gelatin to 100 mL of water and heating to 70oC. What measurement tools would you use to make this solution? Be ready to share 11/24/2018
Objectives Define the international system of units Calculate conversions between metric units Identify scientific tools in the laboratory used for measurement
Purpose Your experimental results will not mean very much if you don’t have a way to attach numbers or non-opinion descriptions to them. The numbers collected must be expressed in units that have the same meaning world-wide Scientists have developed tools to assist in data collection Proper organization of the data allows the scientist to determine what the data really means. 11/24/2018
International System of Units-Metric System Scientists use the metric or SI systems of units for the measurement of physical quantities-length, volume, and mass This system of measurement is used world-wide The metric system is a decimal system of measurement that is scaled on multiples of 10 Prefixes are used in front of the units to indicate powers of ten
Metric System Measurement Base Unit Symbol Mass gram g Length meter m Volume liter L
Metric Prefixes Prefix Symbol Power tera- T 1012 deci- d 10-1 giga- G 109 centi- c 10-2 mega- M 106 milli- m 10-3 kilo- k 103 micro- 10-6 hecto- h 102 nano- n 10-9 deca- da 101 pico- p 10-12
Metric Conversions When converting between metric units, follow these rules Always convert to base units first Ex. To convert cmkm must first convert cm to m then to km Make conversions using the prefix definition Ex. Use the conversion 1 cm = 102 m rather than 1 m = 100 cm
Example Conversion of 6.5 km to m Start with what?
Why do I need to learn this method? You need to fill your swimming pool with your garden hose. The hose releases 1L of water per minute. Your pool holds 1000 kLof water. How long will it take to fill your pool? Can you answer this by moving the decimal point?
Example Conversion of 6.5 km to mm
Practice Problem-complete on note-taker 435 mL L
Practice Problem-complete on note-taker 5.39 g mg
Measurement tools used in Biology
Reading a Meter Stick Meter Stick – major scale division represent centimeters Each cm is further divided into minor scale divisions-0.1 cm or 1 mm divisions
Reading volume in a graduated cylinder Graduated cylinder is marked off in equal units of volumes Usually they are graduated in mLs Most graduated cylinders have Major scale divisions – associated with numbers Minor scale divisions between the numbers Read the volume at the bottom of the meniscus
Use of balance for determining mass In this class, an electronic balance will be used for measuring mass Zero the balance by hitting the Tare button before each measurement Place object on stainless steel tray Read the value for mass If you get the tray dirty, please clean it off
Closure Activity Name two measurement tools discussed in the notes today and explain how they are used in measurement.
Measurement Lab
Constructing well organized Data Tables
Example of a Good Data Table- Effect of fertilizer on plants Date Height in cm of plant Appearance of leaves 4/5/11 10 Leaves are green and there are 2 areas of light green new leaves 4/6/11 All leaves are green and there are 3 areas of light green new growth 4/7/11 11 The plant has 3 areas with light green leaves. The leaves appear to be larger 4/8/11 13 Plant is more spread out and has 5 areas of light green leaves 4/9/11 16 Plant has 5 areas of light green leaves 11/24/2018
Think-Pair-Share Examine the example data table. Write down key characteristics of a data table on your note-taker. Share with a partner 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class 3
Data table characteristics Title Clear labels Dates Column/row labels Units are included Easy to view Straight lines All data can be displayed 11/24/2018
PROPERTY OF PIMA COUNTY JTED, 2010 Minute Paper- think back to the bellwork You have one minute to write down qualitative and quantitative data in the form of a data table that you might take on the new species of plant Be prepared to share. 29. Minute paper or Quick Write teacher provides a prompt from the lesson students have one minute to write down a summary of the key points students compare with a partner teacher uses a strategy to check all PROPERTY OF PIMA COUNTY JTED, 2010 24