The Metric System

Metric System Unit of measurement based on 10 The metric system is also referred to as SI which is the abbreviated French phrase for metric system (System Internationale). Contains sets of prefixes that connect onto the base unit names.

Common Base Unit Names Length = meters Mass = grams Volume = Liters Temperature = Celsius or Kelvin

The Prefixes Kilo- Hecto- Deka- BASE: just unit name Deci- Centi- Milli-

The Prefixes Kilo- 1000 Hecto- 100 Deka- 10 BASE: 1 Deci- .1 Centi- .01 Milli- .001

How to Convert To convert, start with the prefix you are given…..count how many places it takes to get to the prefix you want. 1.5 km = _____cm Kilo-hecto-deka-base-deci-centi-milli Move the decimal as many steps as it took in the line above….AND move the decimal in the same direction. Add in zeros to show place values! 1.5 km = 150000 cm

How to Convert Cont. Kilo-hecto-deka-base-deci-centi-milli 1 mL = ______ cL 4.2 grams = _______kg 56 mm = ________ m 8.9 kL = ________daL

More Practice 3075 mm = _________ cm 6 L = __________ mL .42 cg = ___________g 11 cm = ____________ mm 900 m = ___________km

Measuring Distances

Distance SI unit for distance or length is meters. Tool: meter stick, ruler

Mass: how much matter an object contains. This is NOT weight. Measuring Mass Mass: how much matter an object contains. This is NOT weight.

Measuring Mass SI unit for mass: grams Tool: triple beam balance

How much mass is shown?

How much mass is shown?

Volume: How much space an object occupies Measuring Volume Volume: How much space an object occupies

Volume of a liquid SI unit of volume for liquids: liters or mL Tools: graduated cylinder, beaker (use mL for these tools)

How much volume? Watch out for the meniscus!

How much volume?

How much volume?

Volume: regular shaped objects such as cubes SI unit for regular shaped object’s volume is m3. This is pronounced out loud meters cubed. Tools: ruler or meter stick Multiply LENGTH x WIDTH x HEIGHT.

How much volume? Unit in rectangular prism is mm.

How much volume? A rectangular prism measures 6cm by 2cm by 3cm. How much volume does it have? A cube measures 2cm on each side. How much volume does it have?

Volume: irregular shaped object like a marble SI unit for volume of an irregular shaped object is liters or mL. Tools: beaker or graduated cylinder. Measure the volume of a liquid. Place object into the liquid and record the volume again. Then subtract to find the volume of the object.

How much volume?

How much volume?

How much volume?

Density Density is the amount of mass per unit of volume (D = m/v). It is also used as a physical property to identify unknown samples.

Density SI unit for density is EITHER g/mL or g/cm3 Tools: this is a division problem! Divide mass over volume! The density of water is ALWAYS 1 g/mL. If a rock has a density of 2.4 g/cm3, will it float or sink in water?

How much density? What is the density of a board whose dimensions are 5.54 cm x 10.6 cm x 199 cm and whose mass is 28.6 kg? What is the density of a liquid with a volume of 14.6 mL and a mass of 2.2g?

Variables For any experiment you want to change ONLY ONE variable. A variable is any factor, trait or condition in an experiment that can exist in differing amounts or types. For any experiment you want to change ONLY ONE variable.

Variables (continued) Independent Variable: the variable that YOU personally change or manipulate! This is the whole point of the experiment. What are you trying to find out? Dependent Variable: the variable that changes from performing the independent variable. What are you measuring? The dependent variable is almost always a type of measurement/number. You would look at your data for the dependent variable. Controlled Variable: a variable that is kept constant.

Independent, Dependent & Controlled Variables I want to see if plants grow better with Miracle Gro or natural fertilizer. I would set up three plants in pots that are the same type; receive the same amount of water and sunlight; one pot would receive Miracle Gro, the second pot natural fertilizer, and the third pot nothing added. After 4 weeks of regular watering, I would measure the length of leaf growth on the plants. I would like to find out which battery lasts longer: Duracell, Energizer, or the generic store brand. I would use one flashlight, place one set of batteries inside, and leave the light on until the light begins to fade, keeping track of time. I would repeat this test using the same flashlight but different sets of batteries.

Variables and the Hypothesis When you examine the hypothesis, the independent variable is found after the word IF……..and the dependent variable is found after THEN.

Inferences: To make an inference is to draw a conclusion based on evidence. Ex: You observe the leaves on the tree have turned yellow. Inference? There are dark clouds in the sky. Inference? The school’s phone number is on your caller ID at home. Inference?