Scientific Measurements: The Metric System Credit to A. Rubel

Graphs III. Graphs Used to visually see a change or comparison in data Line graph – shows a change over time

Bar Graphs Bar graph – shows a comparison between 2 or more objects or event

Circle Graphs Circle graph – uses a circle to show a breakdown to show percentages (out of 100%). Colors and patterns are often used to show the differences.

Computing Percentages for a Circle Graph There are 360 o in a circle. If you have 15% to shade, then 360 o x.15 = 54 o So you would mark the 54 o with a protractor.

The Metric System PQ_q59xyw&safety_mode=true&persis t_safety_mode=1&safe=active

SI Units (Metric System) The International System of Measurement (SI) The metric system (SI) – used so scientists everywhere can communicate with each other. Based on the number 10. Major units: Length = meter volume = liters (liquids) or centimeters (solid or liquid) mass = gram/kilogram (measured by a balance instrument)

Length, Mass, and Volume The measurement of mass is the amount of matter that makes up the object; measured in milligrams, grams or kilograms (paperclip = 1g) Volume is the amount of space the object takes up.

Mass vs Weight Mass is the amount of material that makes up an object. (tent vs house) Weight is completely dependent upon gravity and mass of the object. Since gravity varies in different places, then weight can change, but mass does not!

Volume The instrument for volume can be either the meter stick (for a solid -like a box), or a container (like a bottle or container) for a liquid. Volume, as a solid, can be measured in meters. Volume, as a liquid, can be measured in liters. Volume can also be measured in cubic centimeters (cc) If you are finding the volume of an object, then you are using the 3 numbers of the volume formula (length x width x height): 6 m x 2m x 4m = 48m 3

Lab Measurement Instruments A meter stick is used to find length A balance is used to find mass. A scale is used to find weight. A graduated cylinder is used to find volume. The bottom of the curve of the graduated cylinder is called the meniscus.

Volume of a Irregular-Shaped Object If you have an object that you cannot measure with a meter stick (such as a rock), you would 1) Fill a cylinder with water and measure from the meniscus 2) Put in the rock and measure the meniscus 3) Find the difference ( in mL)

How Mass and Volume Affect Density ?v=h5Mkt46Pwog&safety_mode =true&persist_safety_mode=1& safe=active

Density Density – This is a physical property - “thickness” of matter. It is the amount of mass per unit of volume. Formula: mass divided by volume = m/v Example: an object that has a mass of 28g and a volume of 7 28 g 28g 7 ml= 4 g/ ml OR 7 cm 3 = 4g/ cm 3 Question: Does a larger object always have greater density? Which has a greater density, a baseball or a beach ball? WHEN YOU HAVE GREATER MASS COMPARED TO A SMALLER VOLUME, THE HIGHER THE DENSITY. Rate is a ratio between 2 different types of measurement. For example: density is a ratio between mass and volume.

How the Titanic Sank ?v=G8ey_RBdxYM&safety_mod e=true&persist_safety_mode=1 &safe=active

Density is a Physical Property Every element on the periodic table can be identified by a special physical property. Every element has its own specific density. In other words, it doesn’t matter how large or small the sample is, each element would have a specific density. So, if you wanted to identify an element, what are the two things you could find out about it that would prove what the element is?

SI Temperature Temperature: In SI, Celsius is normally used instead of Fahrenheit Conversion: o C = ( o F-32) 1.8 Freezing Point (water): 0 o C Boiling Point (water): 100 o C For extreme temperatures we use Kelvin: K = o C Absolute zero: − o C or 0 K (no heat at all) Kelvin does not use a degree mark.

Temperature Kelvin is different from Fahrenheit and Celcius in that it does not use a degree superscript ( o ).

Absolute Zero Absolute Zero is the temperature in which there is no molecular movement, because there is absolutely no heat energy. Absolute Zero is “as cold as it gets.” Theoretically, Absolute Zero is achieved at 0 K (or o C.) It does not occur naturally, but there have been several attempts to achieve it in a lab setting: