warm-up sept. 11
TRANSCRIPT
Density POGIL Activity September 11, 2014
Warm-Up Sept. 11
1. How many sig figs in each of the numbers. State the rules you used to get your answer.
a. 6.74 10-4 ______ Rule _____
b. 1.7040 109 ______ Rule _____
c. 3.005 102 ______ Rule _____
2. Write the following numbers in scientific notation.
a. 0.00590 ________
b. 3041000 ________
×
x
x
3. Write the following numbers in expanded format.
a. 4.804 108 ______________
b. 9.11 10-7 ______________
4. Compute the following using sig figs. Show work.
a. (4.2 103) (1.6 104)
b. (6.89 104) + (9.24 105)x x
×x
×
x
Density POGIL Activity September 11, 2014
DensitySeptember 10, 2014
What is density?
Density POGIL Activity September 11, 2014
What is density?• Model 1: Mass and Volume
1. How Many Dots in each cube?
A1: 16
A2: 64
A3: 4
A4: 16
What is density?• 2. Based upon Model 1, what is mass?
> How many dots are in a cube
• 3. What can you infer about how much mass each dot represents?> Each dot has the same size, so they
represent the same amount of mass
Density POGIL Activity September 11, 2014
What is density?• 4. As volume increases on the graph’s X-
Axis, what changes about each cube? What evidence from Model 1 supports your thoughts?> The size of the cube increases. Cubes
A2 and B2 are larger than A1 and B1 and they contain more dots
What is density?• 5. Use the following data to calculate the
volume for each of the cubes.
CUBE VolumeA1 8 cm3
A2 32 cm3
B1 8 cm3
B2 32 cm3
Pull
Pull
6. What are the units for volume? Why?- cm3 because you have to add the exponents why you multiply cm1 + cm1 + cm1
Density POGIL Activity September 11, 2014
What is density?• 7. With your group members, create your
own definition of volume.> Amount of space the cube takes up
Pull
Pull
• 8. What is similar about objects A1 and A2?> Tightly packed, a lot of dots,
not much empty space• 9. What is similar about objects B1
and B2?> More space between dots, less
packed
What is density?• 10. Based upon your prior knowledge for
density and the ideas you summarized in questions 8 and 9, create a definition for density with your group members.
Pull
PullDensity is the
amount of mass (dots) in a certain amount of space (size of cube).
Density POGIL Activity September 11, 2014
• 1. Which object is more dense and which is less dense? WHY!?
• The first cube is more dense. Has more matter in same amt of space
Summarizing Questions
• 2. On the graph below, a line has been added to show the density of water. Based upon its density, explain which objects you think will sink and which will float and why.
Summarizing Questions
Material A sinks
Material B floats
Density POGIL Activity September 11, 2014
Liquid Layers• Oil floats on top of water.
Explain why and draw a picture (using dots like in Model 1) to show why this is the case.> Oil is less dense than
water
water
oil
• 4. What is the same between Object C & D?Why is this (based on picture)?
Calculating Density
Pull
Pull
C has less matter in it, but also has smaller volume
Density POGIL Activity September 11, 2014
• 5. How was density calculated using mass and volume values?
Calculating Density
PullPull
DIVIDING MASS BY VOLUME
Calculating density?• 6. Come up with a formula for calculating
density (based on the numbers in Model 2)..• Density = mass OR mass ÷ volume
volume
• Units for density: g ; g cm3 L M
D V ÷×
Density POGIL Activity September 11, 2014
Calculating density?• 7. Do you think that objects C and D are
made out of the same or different material? Explain using evidence from Model 2.
Yes, it is the same material because density is a definite property and does not change for a certain substance.
M
D V ÷×
Calculating Density
• 8.
M
D V ÷×
16 g / 8 cm3 = 2 g/cm3
64 g / 32 cm3 = 2 g/cm3
4 g / 8cm3 = 0.5 g /cm3
16 g/ 32 cm3 = 0.50 g/cm3
Density POGIL Activity September 11, 2014
Calculating Density• 9. Calculate density for the following objects:> a. A 114 gram box that has the
dimensions: length =3 cm, width = 3 cm, height = 7cm
> b. A rock which has a mass of 60 grams and a volume of 20 mL
> c. An unknown liquid with a mass of 10 grams and a volume of 15 mL
M
D V ÷×
114 g / 63 cm3 = 1.8 g/cm3
60 g / 20 mL = 3 g/mL
10 g / 15 mL = 0.7 g/mL