Science 8 Welcome Back!!!

What do you remember. https://www. youtube. com/watch What do you remember???? https://www.youtube.com/watch?v=djTNUp4XIRo metric song On your white board write the… Unit for mass Unit for length Unit for time

What do you remember???? Which is larger? 1.5 kg or 1.5 mg? 10 liters or 10 ml? A pound or a kilogram? A kilometer or a mile?

Can you change metrics? What was the mnemonic you learned???? How many milliliters is in 1.5 liters? How many kilograms are in 230grams? How many mg are in 230 g?

Converting….Kids Have Dropped Dead Converting Metrics 1. 47 mg to ______ grams 2. 1548 ml to _____ liters 3. 5.67 kg to ______ g 4. 15.89 m to _____ km

Answers: 1. 47 mg to 0.047 grams 2. 1548 ml to 1.548 liters 3. 5.67 kg to 5670 g 4. 15.89 m to 0.01589 km

More…… 5. 0.5 l to _____ ml 6. 802 mm to _____ km 7. 0.543 cm to ____ mm 8. 1500 g to ____ kg

5. 0.5 l to 500 ml 6. 802 mm to 0.000802 km 7. 0.543 cm to 5.43 mm 8. 1500 g to 1.500 kg

Rounding…review! Make sure you read directions and round accordingly 123.4567890 Rounded to the nearest… Whole number = 123 Tenths = 123.5 (why .5 and not .4??) Hundredths = 123.46 (why .46 and not .45??) Thousandths =123.457 (the 6 was rounded up to 7)

Measurements…. What tool is used to measure length? What tool is used to measure mass? What tool is used to measure temperature? What tool is used to measure the volume of a liquid?

These are ________ and measure________ The unit most frequently used is the _______

Measure at the bottom of the curved surface.

Each line represents ____?____ milliliters.

What are the volumes shown in each of the cylinders below?

What is the water displacement method? What information can be gleaned from this picture?

What is the mass showed in each picture? Be sure to include units.

Electronic balance – make sure it is measuring in _____

What are the temperatures shown in the pictures?

Graphing Bar graphs are use to …… Pie or circle graphs are used ……. When should the bars touch? Pie or circle graphs are used …….

Bar graph vs histogram Bar graphs are used for data that fits into categories. They often compare data ( how many cars are blue? White?) Bars usually do not touch. Histograms are used with continuous data. ( how many students in VCMS are 10 -14 years old) Spaces are NOT used between data.

Line graphs Used to show changes over time or over distance ALL points on the line MUST have corresponding data

Which variable goes on which axis??? MIX and DRY Manipulated Independent variable on X axis Dependent Responding variable on Y axis

What is the relationship shown on this graph What is the relationship shown on this graph? What are the two variables? Which is the manipulated variable? Which is the independent variable?

What is the relationship shown on this graph What is the relationship shown on this graph? As volume increases, the mass increases. What are the two variables? Volume and mass Which is the manipulated variable? volume Which is the independent variable? volume

What is the relation-ship shown by this graph?

What is the title shown on this graph. What are the two variables What is the title shown on this graph? What are the two variables? Which is the responding variable? Which is the independent variable?

Density What does density measure? What two measurements do you need in order to calculate the density of an object? What is the formula for density?

DENSITY A ratio between mass and volume A measure of how tightly packed the atoms are. Is how much matter occupies a given space The more mass in a given space, the greater the density. Pure substances can be identified by density.

Which has a greater density? 5 grams 10 grams 5 cc 5 cc

Changing the size of the material. 40 cm3 If the first block is cut into two pieces, what happens to the mass? To the volume? To the density?

100 grams 50 grams 50 grams 40 cm3 20 cm3 20 cm3 2.5 g/cm3 2.5 g/cm3 2.5 g/cm3

CHANGING SIZE DOES NOT CHANGE THE DENSITY!!!!

Changing the shape of a material Does the mass change? Does the volume change?

CHANGING SHAPE DOES NOT CHANGE MASS OR VOLUME 40 cm3 100 g 40 cm3

CHANGING SHAPE DOES NOT CHANGE DENSITY! Changing shape does not change mass or volume, therefore the density will not change. When you fold a piece of paper you have not changed the mass or volume. You also have not changed the way the atoms are arranged in that material, therefore the density does not change.

Changing pressure Increasing pressure will cause the atoms to move closer together and the substance will compress. Volume decreases and density will increase. Decreasing pressure allows the atoms to spread apart and the material expands. Volume increases and density decreases. pressure density (DIRECT)

Changing pressure changes volume. 30 mg 10 ml Increase pressure 30 mg 2 ml Increasing pressure changes the volume from 10 ml to 2 ml. The mass remains constant at 30 mg. Density increases from 3.0 g/ml to 15.0 g/ml

Changing temperature changes volume. 40 ml 20 g 10 ml Decrease temperature Decreasing temperature causes the substance to contract and volume decreases. Volume changes from 40 ml to 10 ml. Mass stays constant at 20g. Density changes from 0.5 g/ml to 2.0 g/ml

Changing temperature When temp increases, atoms move faster and spread apart. Volume increases and density decreases. As a material cools, atoms get closer together. Volume decreases and density increases. Temperature density INDIRECT relationship

Draw a graph to show the relationship between: Density Temp Pressure

If you change the substance- add or take away atoms – then the mass to volume may change and the density may change.

Blue 0.8 g/ml pink 0.6 g/ml purple 1.0 g/ml yellow 0.2 g/ml

In the beaker of water below, draw a square that has a density of 0 In the beaker of water below, draw a square that has a density of 0.7 g/ml. Add a triangle that has a density of 1.7. Add a circle with a density of 1.0

The square should be 7/10 below the surface of water The square should be 7/10 below the surface of water. The triangle should be on the bottom. The circle should be suspended in the water.

Phases of matter Solids: Liquids: Gases: For most materials the volume will increase as the material is heated and its density will decrease. temperature volume density

Solids…………..……Liquids…………………..Gases Temperature Energy Volume Density (Are there any exceptions to this??)

WHY??

water

Density of H2O

Water is unique! Water is most dense in the liquid state Water is most dense at 4oC What would happen to aquatic life if this were not true?????

Miscellaneous terms to know: Instruments _ used to extend our senses Classification – to group information together in order to see connections and relationships between things. Dynamic equilibrium – always changing, but maintaining a balance (staying the same) Interface – boundary across which energy flows Observations and inferences

Points to Ponder…. Should the US change to the metric system? Why or why not? How might a construction engineer use the concept of density in his or her day?

END OF INTRODUCTION