Chapter Mass and Volume Mass describes the amount of matter in an object. o Matter – anything that has mass and takes up space. o SI unit for mass is the kilogram.  1 kg = 2.2 pounds  1 gram = kilogram o Mass is measured with a triple-beam balance or electronic scale. o Mass is not the same as weight. Weight measures the pull of gravity on an object. o English unit is the slug or pound. o Related to mass because more mass = more weight. o Weight changes with gravity. < gravity = < weight > gravity = > weight

Volume – amount of space an object takes up. o Basic unit is the m 3 - cubic meter. o Can also be cm 3 or cc. o 1 cm 3 = 1 mL Volume can be measured using 3 different methods. 1.Graduated cylinder - used to measure liquid volume in mL  To read a graduated cylinder: Place on flat surface Read at eye level Read at center – bottom of meniscus – curve of liquid Report measurement to one place value past the value represented by lines on cylinder

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2.Regular, Solid Shape – geometric formulas  Cube or rectangle – length x width x height  Answer will have length units cubed: cm 3, m 3, dm cm x 2.0 cm x 1.0 cm = 12.4 cm 3  1 cm 3 = 1 mL 6.2 cm long 1.0 cm tall 2.0 cm wide

3.Displacement Method Place a volume of water in a graduated cylinder. Make sure the cylinder will hold your object and the water will cover the object. Place a volume of water in a graduated cylinder. Make sure the cylinder will hold your object and the water will cover the object. Measure the water Measure the water Carefully slide the object into the cylinder Carefully slide the object into the cylinder Make a new measurement of the height of the water Make a new measurement of the height of the water Subtract the 2 measurements – Subtract the 2 measurements – the difference is the volume of the difference is the volume of the object! the object!

Calculate the volume of the object in mL

Complete the Chapter 2, Section 1 Worksheet

2.2 Density Mass is not proportional to size – a large object does not always have a large mass. A small object can contain more mass than a large object. Ex: compare a loaf of bread to a brick Density describes how much mass is in a given volume of a material. (how tightly matter is “packed”) o Stated as a ratio of mass to volume o Units can be grams/milliliter; grams/cm 3 ; kilograms/liter o Density of pure water is 1 g/1 mL o Density of a material is the same no matter what the size or shape of the material.  Ex: the density of a steel nail and a steel cube are the same because they are both made of steel.  Exception: water – ice has less density than liquid water

Density formula Density = mass / volume D = m V Ex: A solid wax candle has a volume of 1700 mL. The candle has a mass of 1500 g. What is the density of the candle? D = 1500 g = 0.88 g/mL 1700 mL

Calculate (in your notes) 1.A student measures the mass of five steel hex nuts to be 96.2 g. The hex nuts displace 13 mL of water. Calculate the density of the steel in the hex nuts. 2. A 31.2 g piece of granite measures 2.00 cm x 2.00 cm x 3.00 cm. What is its density? 3. What is the density of ice that has a mass of grams and a volume of 92 cm 3.

1.Calculate the density of your objects. 2.Show all measurements and calculations. 3.Record your densities on the class chart. 4.Copy the class chart, calculate the average densities and turn in. Turn in on Paper

GroupHex NutClay Object Class Average

2.3 Graphing A graph is a visual way to organize data. o Circle graph (pie graph) o Bar graph o Line graph (scatterplot, XY graph)

Circle graph (pie graph) - shows percentages

Bar graph – compares data, often 1 of the variables is not a number

Line graph – compare 2 sets of number data where one variable is thought to cause a change in the other

Line graphs can compare 2 sets of data Easier to read if 2 different colors!!!! Create a legend.

Requirements Independent variable (variable you think will influence another variable) is on X Dependent variable (variable that might be changed by independent variable) is on Y Paper turned so variable with largest spread has more room Covers most of the paper (2/3) Number lines have equal intervals and equal spaces between all numbers – DO NOT have to start with 0 on both axes Axes are labeled with what was measured AND units Points are correctly plotted Best-fit line (NOT connect the dots) Graph has title that relates relationship of information measured

pH of waterNumber of Tadpoles Scientists studying the effect of pH on tadpole populations, collected samples of pond water from 6 local ponds and counted tadpoles in each pond. The data is recorded in this chart. Create a line graph of the data following the rules you were given.

Check Your Work Did you: Place pH on the X axis? Tadpoles on Y axis? 10 pt Turn your paper so tadpole numbers have the longest part of the paper? 10 pt Cover 2/3 of your paper? 10 pt Space your number intervals correctly and equally? 10pt Label Axes with what was measured? 10 pt Correctly plot values? 30 pt. Best-fit line? 10pt Create an acceptable title? 10 pt.

A clam farmer has been keeping records concerning the water temperature and the number of clams developing from fertilized eggs. Make a line graph of the data. Water Temperature in o C Number of developing clams ? Oops, forgot to record!

Answer on the bottom of your graph. 1. What is the dependent variable? 2. What is the independent variable? 3. What is an estimate of the number of clams at 35 o C? 4.What is the optimum (best) temperature for clam development?

Identifying graph relationships In a direct relationship, when one variable increases, so does the other. The speed and distance variables show a direct relationship.

In an inverse relationship, when one variable increases, the other decreases.

Interpolation Method of determining a new data point that exists between a set of known data points

Scientific Notation Simple way of writing numbers with many digits Number x 10 to a specific power Ex: x

Scientific Notation The exponent of 10 tells the person reading the direction the decimal must be moved to obtain the number written in long notation Example: km = 6.5 x 10 4 km mm = 1.2 x mm A positive exponent means “ x10” to that power A negative exponent means “dividing by 10” to that power 27

Expressing Scientific Notation in Full Form Rewrite the number in front of “x10” Determine if decimal should be moved left or right. –Negative exponent tells reader to move left –Positive exponent tells reader to move right If adding zero’s on end – DO NOT add decimal to full number! If adding leading zero’s – add the decimal. Remember, leading zero’s are not sig fig’s Ex: 7 x 10 4 = Ex: 2.31 x = 28

Expressing Scientific Notation in Full Form 1.56 x x x x

Expressing a number in Scientific Notation 1.Rewrite numbers leaving off zero’s on the end or zero’s in front of first “non-zero”. 2.Place a decimal after the first number - only 1 number allowed in front of the decimal 3.State “x 10”. To determine how many places the decimal should be moved – count how many place values to where the decimal started. 4.If the decimal needs to be moved right, exponent is “positive”. If the decimal needs to be moved left, exponent is “negative”. Ex: = Ex: = 30

Expressing a Number in Scientific Notation

Complete and Turn in Convert into scientific notation: m mm L g 32 Convert into full notation: x x x x x 10 -7

State the following numbers in scientific notation 1) ) ) ) )0.06 State the following scientific notation in standard form 6)6.17 x )7 x )7.31 x )6.7 x )9.59 x Make up