Properties of Matter Anything in red type or on a red slide, you do not need to put into your notes. Everything else, you are expected to put into your notes.
Pre-Assessment Questions • What is matter? • Can you give an example of matter? • Are mass and volume the same thing? • What is density?
You Table Dog Pop Water Air Carbon dioxide Light Which of these are matter?
Matter has physical properties. • Physical properties – characteristics that can be used to identify and describe materials. Any property that can be observed or measured is a physical property. • Examples include: color, shape, brittleness, density, length, width, height, mass, and volume.
Measuring Mass • Mass is the amount of matter (number of atoms) in an object. • Mass does NOT change unless you add or subtract matter. • In this demonstration, how could I change the mass of the water?
We measure mass with a balance scale. Steps in using a triple-beam balance: • Carry the scale carefully using both hands. (They cost about $100 each, so please treat them nicely.)
Zero the scale - first move all the masses to the zero position, see if the line is at zero. If not, gently turn the knob at the end and allow it to balance. Repeat until the line is at zero.
Put the object on the pan. • Move the masses until the lines are lined up. • Record the total mass.
Practice using the triple beam balance scales. • Get a partner and one scale for both of you to use. • Zero the scale. • Take turns measure the masses of objects such as a pen or pencil, a planner, a ruler, a glue stick, or other reasonably small object. • When you are both confident in using the scale, call your teacher over to test you.
Mass is measured in grams. • 1000 grams = ____ kilogram • 1 gram = ____ milligrams
Measuring Volume • Volume is the amount of space an object occupies. • Solids and liquids have a definite volume – that means you can’t change it without adding or subtracting matter.
Gases can compress or expand to the size of their container, so their volume can change; it’s NOT definite. • Watch the demonstration. Which type of matter can be squeezed into a smaller space?
We measure the volume of liquids with a graduated cylinder. • Graduated cylinders are made of glass and will break if dropped. Please be careful with them!!
Steps in using a graduated cylinder: • Put the liquid in it. • Place it on a flat surface.
Get down to read it at eye level. • Read it at the bottom of the smile (meniscus).
Practice using the graduated cylinder • With a partner, get a graduated cylinder. • Try to get exactly 50 ml of water in it. • Have your partner check you. • Repeat for different amounts until both of you are confident in using it. • Call your teacher over to quiz you.
Volume is measured in liters. • 1000 liters = ____ kiloliter • 1 liter = ____ milliliters
We measure volume of a regular solid by using math. • To find the volume of a box you multiply length times width times height. • V = l x w x h
Example: • A box has a length of 10 cm, a width of 5 cm and a height of 2 cm. Find volume. • V = l x w x h • V = 10 cm x 5 cm x 2 cm • V = 100 cm3 • cm times cm times cm = cm3
Time to try finding volume in a mini lab! • Get a partner and find the volume of at least 2 of the boxes in lab. • Write down each measurement and your final answer.
The Box Volume Lab • Get the lab sheet and follow the instructions carefully! • Link to the lab sheet!
We find volume of an irregular solid using the submersion method: • An example of an irregular solid is a rock. • To find its volume: • Put water into a container such as a graduated cylinder. • Note how much water there is. • Put the object in and the water rises. • Note how much the water rose and that’s the volume.
Why does this work? • Since volume is the amount of space an object takes up, when you put an object in water it displaces the water. This means that the water still takes up the same amount of space for itself plus the amount of the object, so the water rises the amount of the volume of the object.
Time for you to try in lab. • With a partner find the volume of one or two of the irregular objects. • Call your teacher over when you are confident you know what you are doing.
Okay, now that you understand mass and volume, let’s put them together.
Which weighs more – a pound of feathers or a pound of lead? • Actually, they weigh the same. But which takes up more space?
Density • Density is a measure of how closely packed the atoms are in a substance. • density = mass divided by volume • d = m/v
An example: • An object has a mass of 30 grams and a volume of 6 milliliters. What is its density? • m= 30 g v= 6 ml • d=m/v d= 30g/6ml • d=5 g/ml
mass=100 grams, volume=20 ml mass=7 grams, volume=14 ml mass=40 grams, volume=5 ml Answers: 5 g/ml .5 g/ml 8 g/ml You try a couple density problems!
Time for a lab!Density Lab 1 Get a partner. Open a new spreadsheet and write down the question. • Question: How do you think we could find out the density of water?
Next do background research, and a hypothesis. Then we will discuss your ideas about how to do this lab. And then everyone can do the lab after we agree on the experimental procedure.
Density Quiz • What is the equation for density? • I have two cube shaped objects that have identical volumes. Cube A has a mass of 100 grams and cube B has a mass of 70 grams. Which cube has a higher density? • A box has a mass of 20 grams and a volume of 5 cm3. What is its density with units?
A sample of liquid has a volume of 7 ml and a mass of 35 grams. What is its density? • I have a liquid of unknown density. What two pieces of lab equipment would I use to find density? • I have a box of unknown density. What two pieces of lab equipment would I use to find density? • I have an oddly shaped rock of unknown density. What two pieces of lab equipment would I use to find density?
Quiz Answers • d=m/v • Cube A • 4 g/cm3 • 5 g/ml • Graduated cylinder and balance scale • Ruler and balance scale • Graduated cylinder and balance scale (and maybe a beaker)
Density Lab 2 • Open a new spreadsheet and type in the problem: Rank the five objects in order of increasing density. • For background research give the definitions for mass, volume, and density and the equation for density
For your hypothesis pick up and look at each of the objects and make your best educated guess in ranking them from lowest to highest density. • Next, decide how you will find out if your hypothesis is correct and write down the steps of your experimental procedure.
Make a data table in the spreadsheet for your results. The table should have columns for object, mass, volume, density, and rank. • Do the experiment and fill in the results in your table. • For your conclusion list the objects in order of increasing density. • To verify ask another group that used the same objects if your results agree with yours.