Activity Five: Density

http://phet.colorado.edu/

Neutral Boron Atom:

Proton:   5


Neutrons:  5


Electrons:  5


Density:  2.34 g/cm³

Neutral Lithium Atom:

Proton:  3


Neutrons:  3


Electrons:  3


Density: 0.534 grams per cubic centimeter




2. Define density and the equation for density.

    According to our class book, Chemisty for Changing Times by John Hill, density is the quantity of mass per unit volume. The equation of density is mass divided by volume or simply d=m/v.

3. Run the Density simulation http://phet.colorado.edu/en/simulation/density and complete one of the prepared Teaching Ideas.

I preformed the Density and Bouyancy lab by Milton Johnson and completed the worksheet (which is below in gray).

PhET- Density Activity- Funsheet

Custom Section                                                                    Name: Taylor Molitor

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
Styrofoam	.75kg	5.00L	0.15kg/L	Yes
Wood	2.00kg	5.00L	0.40kg/L	Yes
Ice	4.60kg	5.00L	0.92kg/L	Yes
Brick	10.00kg	5.00L	2.00kg/L	No
Aluminum	13.50kg	5.00L	2.70kg/L	No

1.      In the custom setting, choose the ‘My Object’ option in the material drop down box.  Set the mass of your object to 4 kg.  Adjust the volume to find the minimum volume needed to make the object float.

Volume: 4.01L            Density: 1.00kg/L

2.      How does the density of a large piece of aluminum compare to a small piece?

It’s the same density no matter the size of the aluminum.

Same Mass Section

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
Blue	5.00kg	5.00L	1.00kg/L	No
Yellow	5.00kg	5.00L	1.00kg/L	Yes
Green	5.00kg	2.50L	2.00kg/L	No
Red	5.00kg	1.25L	4.99kg/L	No

Same Volume Section

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
Blue	6.00kg	5.00L	1.20kg/L	No
Yellow	8.00kg	5.00L	1.60kg/L	No
Green	4.00kg	5.00L	0.80kg/L	Yes
Red	2.00kg	5.00L	0.40kg/L	Yes

3.  Looking at the data on the previous page, what must be true about the density of

     an object in order for it to float?

In order for the object to float, the density of the object must be less then 1.00kg/L and sometime equal to that.

Same Density Section:

4.  Calculate the density of the blue object in this section.

     Mass ____3.00kg______         Volume____3.00L_______        Density_____1.00kg/L_______

5.  Explain why both the yellow and red objects float when they have different sizes.

Both of these objects float because both of them have a density equal to 1.00kg/L.

Mystery Section:

6.  Before you start, pick an object that you think will float.  ______Object B___________

     Pick an object that you think will sink.  ________Object E__________

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
A	64.14kg	3.38L	18.98kg/L	No
B	0.64kg	0.64L	1.00kg/L	Yes
C	4.08kg	4.08L	1.00kg/L	Yes
D	3.10L	3.10L	1.00kg/L	Yes
E	3.53kg	1.00L	3.53 kg/L	No

7.  In the Custom section describe the difference between how Styrofoam and ice  

     floated.  Also explain why you think this is the case?

In the custom section, the ice floated but was mostly under the water, while the Styrofoam was floating mostly on top of the water. I think this is because even though they have the same density, the ice is more of a solid object while Styrofoam has more air in it. Styrofoam also has less of a volume then ice does.

8.  In the Same Mass Section discuss what was interesting about the blue object’s behavior in the water.

The blue object did not float at the surface of the water, but if you drug it into the middle of the water and let go it would sit wherever you put in under the water.

9.  In the Mystery Section, click on the “Show Table” button.  What is the most dense   

     object on the list?  Write its density as well.

The most dense object in the mystery section is a piece of gold and it’s density is 19.3kg/L

10.  List something you learned from this activity.

In this activity, I learned that in ordered for something to float, it’s density needs to be less than or equal to 1.00, but even when the density of an object is 1.00 it still may not float above water, like in the same mass section with the blue object.

4. Complete the Mystery Blocks activity on the Density simulation.  Post on your blog the data you collected (mass, volume, and density) and the identification of the material and the known density.

 Object        Mass        Volume        Density         Identification   Known density 
                                                                                      (Based on table)
Object A:   64.14kg       3.38 L        18.98kg/L            Gold           19.30 kg/L
Object B:   0.64 kg        0.64 L        1.00 kg/L             Water         1.00 kg/L
Object C:   4.08 kg        4.08 L        1.00 kg/L             Water         1.00 kg/L
Object D:   3.10 kg        3.10 L        1.00 kg/L             Water         1.00 kg/L
Object E:   3.53 kg        1.00 L        3.53 kg/L            Diamond     3.53 kg/L



5. Identify the Science Standards that could be met through these activities completed.

This experiment meets a few different Science Standards of Wisconsin for a fourth grader.  These standards are:

• B.4.1 Use encyclopedias, source books, texts, computers, teachers, parents, other adults, journals, popular press, and various other sources, to help answer science-related questions and plan investigations
•  C.4.2 Use the science content being learned to ask questions, plan investigations, make observations, make predictions, and offer explanations
•  C.4.4 Use simple science equipment safely and effectively, including rulers, balances, graduated cylinders, hand lenses, thermometers, and computers, to collect data relevant to questions and investigations
•  C.4.5 Use data they have collected to develop explanations and answer questions generated by investigations