Packet #3 Chapter #1

Introduction In class, two “quantities,” volume and mass, have been mentioned and are measured using a particular type of unit. What are some of the other “quantities” and units used in science?

Quantities & Units QuantitySymbolUnitAbbreviation Lengthlmeterm Massmkilogramkg Timetseconds TemperatureTkelvinK Amount of a substance nmolemol Electrical currentIampereA Volumevmillilitreml

Prefixes PrefixAbbreviationExponential Multiplier MeaningExample using length Kilo-k kilometer (km) = 1000 meters (m) Hecto-h hectometer (hm) = 100 m Deka-da dekameter (dam) = 10 m Deci-d / 10 (0.1)1 decimeter (dm) = 0.1 m Centi-cm / 100 (0.01)1 centimeter = 0.01 m Milli-mm / 1000 (0.001)1 millimeter = m

Conversions I Within quantities, it is important for scientists to convert a measurement from one unit to another. Let us do some examples.

Conversions II Identify the quantity and unit given and the unit that you want to convert to. Using the equality that relates the two units, set up the conversion factor that cancels the given unit and leaves the unit that you want to convert to. Multiply the given quantity by the conversion factor. Cancel units to verify that the units left are the ones you want for your answer.

Conversions III Examples

Density I Is a physical property of matter The quality or condition of being dense. A measure of “thickness” Density = Mass / Volume

Densities of Various Substances SubstanceDensity (g/cm 3 ) at 25°C Hydrogen Gas (H 2 ) Carbon Dioxide (CO 2 ) Ethanol (ethyl alcohol) (C 2 H 5 OH)0.789 Water (H 2 O)0.997 Sucrose (table sugar) (C 12 H 24 O 12 )1.587 Sodium Chloride (Salt) (NaCl)2.164 Aluminum (Al)2.699 Iron (Fe)7.86 Copper (Cu)8.94 Silver (Ag)10.5 Gold (Au)19.3 Osmium (Os)22.6

Introduction Everyone knows that vegetable oil floats on water. That’s because the two liquids have different densities. Density is basically how much “stuff” is smashed into a particular area… or a comparison between an object’s mass and volume. So, the exact same volume of two liquids may actually have different masses, so they would have different densities. That’s why vegetable oil floats on top of water. But, vegetable oil and water are just one way to explore density. What if you could float seven different liquids in seven different layers? We’ll show you how to be amazing and make a seven-layer density column!

Materials Light Karo Syrup Water Vegetable Oil Dawn dish soap (blue) Rubbing alcohol Lamp Oil Honey Graduated cylinder Food Coloring or True Color Coloring Tablets Food baster 9 oz. portion cups

Lab Instructions Measure 8 ounces {235 ml} of each type of liquid into the 9 oz. portion cups. You may want to start the experiment by coloring each of the liquids to make a more dramatic effect in your column. Light Karo syrup is easier to color than the dark syrup. The only liquids that you may not be able to color are the vegetable oil and the honey.

Lab Instructions II Start your column by pouring the honey into the cylinder. Now, you will pour each liquid SLOWLY into the container, one at a time. Make sure you pour them in the following order. Honey Karo syrup Dish soap Water Vegetable oil Rubbing Alcohol Lamp oil

Lab Special Note It is VERY important to pour the liquids slowly and into the center of the cylinder. Make sure that the liquids do not touch the sides of the cylinder while you are pouring. Also, it’s okay if the liquids mix a little as you are pouring, the layers will always even themselves out because of the varying densities. As you pour, the liquids will layer on top of one another. After you pour in the liquids you will have a Seven-layer science experiment. Density is too cool!

Observations & Why I The same amount of two different liquids will have different weights because they have different masses. The liquids that weigh more (have a higher density) will sink below the liquids that weigh less (have a lower density). To test this, you might want to set up a scale and measure each of the liquids that you are pouring into your column. Make sure that you are measuring the weights of equal portions of each liquid. You should find that the weights of the liquids correspond to each different layer of liquid. For example, the honey will weigh more than the Karo syrup, etc. By weighing these liquids, you will find that density and weight are closely related. Here are the densities of the liquids used in the column as well as other common liquids (measured in g/cm3):

Observations & Why II