Post on 25-Dec-2015
Pre-Assessment QuestionsPre-Assessment Questions
What is matter?What is matter? Can you give an example of matter?Can you give an example of matter? Are mass and volume the same Are mass and volume the same
thing?thing? What is density?What is density?
Matter – anything Matter – anything that takes up that takes up space and has space and has massmass
Which of these are matter?Which of these are matter?
YouYou TableTable DogDog PopPop
WaterWater AirAir Carbon dioxideCarbon dioxide LightLight
Everything in the Everything in the universe is either universe is either MATTER or ENERGY.MATTER or ENERGY.
Matter has physical properties.Matter has physical properties.
Physical properties – characteristics Physical properties – characteristics that can be used to identify and that can be used to identify and describe materials. Any property describe materials. Any property that can be observed or measured is that can be observed or measured is a physical property.a physical property.
Examples include: color, shape, Examples include: color, shape, brittleness, density, length, width, brittleness, density, length, width, height, mass, and volume.height, mass, and volume.
Measuring MassMeasuring Mass
Mass is the amount of matter Mass is the amount of matter (number of atoms) in an object.(number of atoms) in an object.
Mass does NOT change unless you Mass does NOT change unless you add or subtract matter.add or subtract matter.
In this demonstration, how could I In this demonstration, how could I change the mass of the water?change the mass of the water?
Measuring VolumeMeasuring Volume
Volume is the amount of Volume is the amount of space an object occupies.space an object occupies.
Solids and liquids have a Solids and liquids have a definite volume – that definite volume – that means you can’t change it means you can’t change it without adding or without adding or subtracting matter.subtracting matter.
Gases can compress or Gases can compress or expand to the size of their expand to the size of their container, so their volume container, so their volume can change; it’s NOT definite.can change; it’s NOT definite.
Watch the demonstration. Watch the demonstration. Which type of matter can be Which type of matter can be squeezed into a smaller squeezed into a smaller space?space?
We measure the volume of We measure the volume of liquids with a graduated liquids with a graduated
cylinder.cylinder.
Graduated cylinders are Graduated cylinders are made of glass and will made of glass and will break if dropped. Please break if dropped. Please be careful with them!!be careful with them!!
We measure volume of a We measure volume of a regular solid by using math.regular solid by using math.
To find the volume of a To find the volume of a box you multiply length box you multiply length times width times height.times width times height.
V = l x w x hV = l x w x h
Example:Example: A box has a length of 10 cm, a A box has a length of 10 cm, a
width of 5 cm and a height of width of 5 cm and a height of 2 cm. Find volume.2 cm. Find volume.
V = l x w x hV = l x w x h V = 10 cm x 5 cm x 2 cmV = 10 cm x 5 cm x 2 cm V = 100 cmV = 100 cm33
cm times cm times cm = cmcm times cm times cm = cm33
We find volume of an irregular solid We find volume of an irregular solid using the submersion method:using the submersion method:
An example of an irregular solid is a An example of an irregular solid is a rock.rock.
To find its volume: To find its volume: 1.1. Put water into a container such as a Put water into a container such as a
graduated cylinder.graduated cylinder.2.2. Note how much water there is.Note how much water there is.3.3. Put the object in and the water rises.Put the object in and the water rises.4.4. Note how much the water rose and Note how much the water rose and
that’s the volume.that’s the volume.
Why does this work?Why does this work?
Since volume is the amount of space Since volume is the amount of space an object takes up, when you put an an object takes up, when you put an object in water it displaces the water. object in water it displaces the water. This means that the water still takes This means that the water still takes up the same amount of space for up the same amount of space for itself plus the amount of the object, itself plus the amount of the object, so the water rises the amount of the so the water rises the amount of the volume of the object.volume of the object.
Which weighs more – a pound of Which weighs more – a pound of feathers or a pound of lead?feathers or a pound of lead?
Actually, they weigh the same. But Actually, they weigh the same. But which takes up more space?which takes up more space?
DensityDensity
Density is a measure of how closely Density is a measure of how closely packed the atoms are in a substance.packed the atoms are in a substance.
density = mass divided by volumedensity = mass divided by volume d = m/v d = m/v