Notes on Making Measurements

Measuring in SI Standard system of measurement is the International System of Units (abbreviated SI) Based on multiples of 10

Tips for making measurements Know the purpose of your measurement. Choose the most suitable size unit, such as cm for a book or m for the classroom floor. Know how your measuring tool works, including what main unit it measures and what the smaller units mean. Label your measurements with the units used. Determined whether you will need one, two, or a series of measurements. Figure out whether you will have to perform any math operations. Know any special rules that apply. For example, read the water level in a graduated cylinder at eye level and at the lowest point of the curved surface. For mass, find the mass of a container alone and subtract that mass from the combined mass.

Length Unit of measure is a meter Use metric rulers and meter sticks to measure Line up zero line at one end of object Measure your length Don’t forget the units!

Area and Volume Knowing length, width, and possibly height, it is easy to calculate area and volume Area = length x width (units squared) Volume = length x width x height (units cubed)

Liquid Volume Amount of space an item takes up Measured in Liters (L) or milliliters (mL) For irregular shaped objects, use a graduated cylinder = displacement Measure at the lowest point of the meniscus

Mass Amount of matter in an object Measured in grams (g) or kilograms (kg) Use a balance Zero the balance, put your object on, and it will tell you the mass

Temperature Measured in o Celsius Use a thermometer Water freezes at 0oC and boils at 100oC

Computers and Calculators Computers can be used to organize and analyze data quickly and accurately. May be used to generate graphs or run simulations as well May be used to help scientists communicate with each other

Microscope Compound light microscopes magnify objects Objective x Eyepiece = how much larger the object is than can be seen with your naked eye Electron microscopes – can see even smaller objects (not available in schools)