8th Grade Integrated Science Math in Science 8th Grade Integrated Science

Measurement Systems The Metric System The two systems of measurement used in the world are English and Metric The US uses the English system Most other countries use the metric system The metric system is based on powers of ten English units of measure (and what they measure) Metric Units of measure (and what they measure)

Measurement Systems In science we only use the metric system of measurement to collect data Examples of units of measure in the metric system: Length -- meters, centimeters, kilometers; the base unit is the meter Mass- grams, milligrams; the base unit is the gram Volume – liter, milliliter; the base unit is the liter

Converting within the metric system When moving from one unit to a smaller unit When moving from one unit to a larger unit

Converting within the metric system There is an easier way to convert in the metric system!!! You just have to remember this mnemonic device and fill in the stair steps…. King Henry Died base unit Drinking Chocolate Milk

Graphs and Graphing First let’s review…. https://www.youtube.com/watch?v=l0jTMDtX4WY Experimental Design Experiments are made up of two groups: Control Group – does not include the thing we are testing, used for comparison Experimental Group – contains the thing we are testing or the independent variable Variables Independent Variable- The difference between the control and the experimental group, determined before the experiment, the thing changed by the scientist Dependent Variable –The thing we measure during the experiment, also called data _______________________________________________________________________________

Graphs and Graphing Types of graphs What is each used for? 1.) Line graph – used to show a change over time 2.) Bar graph – used to compare things, good for surveys 3.) Scatter plot – used to show a correlation (or relationship) between two variable --positive correlation --negative correlation --no correlation

Graphs and Graphing S Scale U Units L Labels T Title A Accuracy Parts of the graph and graphing When creating graphs in science make sure to follow the SULTAN checklist S Scale U Units L Labels T Title A Accuracy N Neatness

Graphs and Graphing– SULTAN (cont.) Scale - graph should take up whole page (>80%), each line is worth the same value, the numbers are evenly spaced; allows us to see the trend in data easily How to find the proper scale (for most cases) Count the number of boxes on each axis and jot that number down somewhere. Divide the range (range is difference between the highest value and the lowest value for that data set) by the number of boxes on that axis. If the number is a decimal you will always round up to the next whole number. You have to round up to keep your graph inside your axes, if you do not your data will go off of the page. This number will be your scale for that particular axis. **This step also has to be followed for each separate axis. Scale = Range / Number of Boxes

Graphs and Graphing- SULTAN (cont.) Units- what the numbers on the scale are measuring, (m), (s), (oC) Labels- Describe what is being measured; length, time, temperature Remember the following D –Dependent R- Responding Y- axis M- Manipulated I- Independent X- axis

Graphs and Graphing– SULTAN (cont.) Title- Placed across the top of the graph, short summary of what the graph shows; DO NOT simply restate the independent and dependent variables; ie. Number of waves vs. Time Accuracy - data is plotted precisely, key included if necessary Neatness – lines drawn with a ruler, easy to read

Graphs and Graphing—Types of Graphs Line Graphs Used to show a change over time Shows how the dependent variable is related to or changes due to the independent variable Line Graph Relationships Descriptions of how two variables relate to each other Direct Relationship – BOTH variables increase or BOTH variables decrease Cyclic – Pattern on graph repeats over time Static – As the independent variable increases, the dependent variable stays the same Indirect Relationship – When one variable increases, the other decreases

Graphs and Graphing- Types of Graphs Bar Graphs Used to compare things, good for surveys If there is data for multiple groups, bars can be side by side or stacked If there are multiple bars for a category a KEY is necessary

Graphs and Graphing- Types of Graphs Scatter Plot Used to determine if there is a correlation or relationship between two variables Positive Correlation- as one variable increases so does the other Negative Correlation- as one variable goes up, the other goes down No correlation- no apparent relationship between the variables

Mass, Volume and Density The amount of matter in something Units = grams Tool used to measure = balance Volume The amount of space something takes up Units = cm3 or mL Tool used to measure = ruler or graduated cylinder

Mass, Volume and Density Volume (continued) Two methods for finding volume: Regular object (regular object = flat sides) Use a ruler or meter stick and measure length, width and height Formula = Length x width x height cm x cm x cm = cm3  we measured 3 dimensions so units are cubed Irregular object (for example a mineral or rock) Water displacement – use a graduated cylinder Fill graduated cylinder with water, leave room at the top, note the amount of water Put object in graduated cylinder, note new water level Subtract value in #1 from value in #2 Your answer for #3 is the volume with mL as the units

Mass, Volume and Density The amount of matter in a specific volume Can be used to help identify an unknown substance Units = g/cm3 or g/mL Tools used to measure = balance, and ruler or graduated cylinder Density of water is 1 g/cm3 or 1 mL If an object is placed in water and floats, its density is less than 1 g/cm3   If an object is placed in water and it sinks, its density is greater than 1 g/cm3

Mass, Volume, Density Density = Mass Volume Volume = Mass Density Mass = Density x Volume Density of an object remains the same, no matter how many pieces its broken into