Tools and Measurement

Master scientific measurement tools and SI units for accurate science observations!

Section Summary Scientists use descriptions and explanations when observing natural events. There are two types of descriptions. When making a qualitative description, such as “The lava is bright red,” you use your senses (sight, sound, smell, touch, taste) to describe an observation. When making a quantitative description, such as“The lava has a temperature of 630oC,”you use numbers and measurements to describe an observation. At one time, scientists in different parts of the world used different units of measurement resulting in confusion. Sharing scientific information was difficult, if not impossible. In 1960, scientists adopted a new system of measurement to eliminate this confusion. The International System of Units (SI) is the internationally accepted system for measurement. SI uses standards of measurement calledbase units. Base units for length, volume, and mass are meters, liters, and gramsrespectively. In addition to base units, SI uses prefixes to identify the size of the unit. Prefixes are used to indicate a fraction of ten or a multiple of ten. In other words, each unit is either ten times smaller than the next larger unit or ten times larger than the next smaller unit. For example, the prefix centi- means 1 A centimeter is 1 of a meter. The prefix kilo- means 1,000. A kilometer is 1,000 m. You can simply convert from one SI unit to another by multiplying or dividing by a factor of ten. The table below shows the prefixes and their values. As you engage in scientific inquiry, you will need tools to help you take quantitative measurements. Rulers and meter sticks measure lengths and distances. Beakers hold and pour liquids, while graduated cylinders measure the volume of a liquid. Volume is the amount of space an object occupies. A triple-beam balance is used to measure mass. Mass is the amount of matter in an object. The United States uses another system of measurement known as the imperial or customary system. It is not as logical as the metric system but it continues to be part of our culture and everyday life. Units include inches and miles for length cups, pints, quarts, and gallons are used for volume; and mass is measured most often in pounds. The conversion values vary and can be more confusing, therefore the metric system is used more often in science and internationally. Measuring Tools Match the name of each instrument with its picture. meter stick ruler graduated cylinder triple-beam balance Thermometer Write the metric abbreviation for each word. milliliter mLkilometer kmcentimeter cmgram g Write the word for each metric abbreviation. (Spelling counts! Look up spelling before you submit!) m metermg milligrammm millimeterkL kiloliter Reasonable Units Match each metric unit that would best be used to mearsure the given items. gasoline for your car liter (L) width of a soccer field meter (m) temperature of water degrees Celcius (oC) medicine milligram (mg) The diagram below shows a ball held in place by two blocks. The diameter (width) of the ball is shown between the two blocks.What is the diameter of the ball? 17.0 cm 14.0 cm 8.0 cm 6.0 cm Tools and Measurement Match the Tool with what they Measure. Graduated Cylinder Volume Triple Beam Balance Mass Meter Stick Length Measuring Sort the information into the correct category. Mass Measured in grams The amount of matter in an object (Solids, liquids, gases) Measured with Electronic Scales and Triple Beam Balances. Volume Liquids and irregular objects are measured in Liters or milliliters. Regular objects are measured in cm3 Measured with Graduated Cylinders The amount of space an object takes up. Apply your measuring skills. Use the image to answer the questions below. What is the measurement of the blue line above the metric ruler? (Choose two answers!) 2.7 cm 2.8 mm 2.8 cm 28 mm Applying your Measurement Skills Use the picture to answer the questions below. The mass showing on the triple beam balance is 125.9 g The volume of the liquid 37 ml