Activity 5: Density
One of the most common attributes of chemical materials that we observe and feel on a daily basis is the density of materials. One of the things we notice in the structures of atoms, is that the atom is mostly space, with a small heavy nucleus and very light electrons orbiting the nucleus. So, how heavy something feels is related to how many protons and neutrons are in the nucleus of atoms that make up molecules. For example, aluminum is much lighter than iron. The "heaviness" of a material is quantified through a characteristic called density.
For this activity, and future ones, we will introduce the usage of simulations and gaming to aid in our understanding of chemical principles. The simulation package we will utilize can be found at this site:
http://phet.colorado.edu/
There are many of this types of things being developed on the web, I have found this one to be excellent for many reasons.
1. It is free! This is an activity supported by the National Science Foundation and many others to aid students and educators.
2. I find the interface to be easy and good for entry level science students and even advanced students. I have found that my 2nd grade son can use these simulations.
3. The science principles covered are very good, and the simulations are quite "real."
4. There is a developing support community for these simulations. For example there is a section for teachers in which there are pre-developed activities and a way to share your own activities.
For future educators and parents, I encourage you to encourage your future school districts to utilize these types of simulations in science education. Students tend to become engaged, and it can alleviate some of the costs and struggles of doing actual experiments in the classroom.
To complete Activity 5, complete the tasks below:
1. Run the Build an Atom simulation http://phet.colorado.edu/en/simulation/build-an-atom and build a neutral lithium atom and a neutral boron atom. Take a picture, or a screen shot, of these two atoms and place them on your blog. List the number of protons, neutrons and electrons for each. Also look up and post the density for each of the elements on your blog.
 |
Lithium
Abbreviation= Li
Protons= 3 Neutrons= 4 Electrons= 3
Density= 0.53 g.cm -3
|
 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Boron
Abbreviation= B
Protons= 5 Neutrons= 6 Electrons= 5
Density= 2.34 g/cm3
2. Define density and the equation for density and post on your blog.
DENSITY is a physical property of matter, as each element and compound has a unique density associated with it. Density defined in a qualitative manner as the measure of the relative "heaviness" of objects with a constant volume. The formal definition of density is mass per unit volume. Usually the density is expressed in grams per mL or cc. Mathematically a "per" statement is translated as a division. cc is a cubic centimeter and is equal to a mL Therefore,
volume (mL) http://www.elmhurst.edu/~chm/vchembook/120Adensity.html 3. Run the Density simulation http://phet.colorado.edu/en/simulation/density and complete one(your choice) of the prepared Teaching Ideas and post your results on your blog. The activity you choose should be one of the student intended activities.
PhET- Density
Activity- Funsheet
Custom Section Name_____________
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______10___________ Density_______0.40___________
2.
How does the density of a large piece of aluminum
compare to a small piece?
The density never changes.
Same Mass Section
Same Volume Section
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?
The density has to be 1 or less in order to float in water.
Same Density Section:
4. Calculate the
density of the blue object in this section.
Mass
____3_________
Volume______103.75_________
Density______0.2133_______
5. Explain why both
the yellow and red objects float when they have different sizes.
Because their density is less than 1 and the density of water is 1kg/L.
Mystery Section:
6. Before you start,
pick an object that you think will float.
____________Yellow__A_____________
Pick an object
that you think will sink.
_________Blue__B______________
7. In the Custom
section describe the difference between how Styrofoam and ice
floated. Also explain why you think this is the case?
The mass on the styrofoam and its weight was much less than the ice. The ice floated mostly under the water and styrofoam stayed way above the water line. Ice is frozen water so I assume that is why is floated mostly below the water.
8. In the Same Mass
Section discuss what was interesting about the blue object’s behavior in the
water.
Sometimes the object floated and other times it sunk. It must have had a mass very close to 1 kg/L like 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.
Gold 19.3
10. List something
you learned from this activity.
I learned that an object will sink if its density is greater than water. I also learned that the volume of the object will not make it sink the only way it will sink is depending on its density.
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. |
No comments:
Post a Comment