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
Protons:3
Neutrons:3
Electrons:3
Density: 0.534 g·cm−3 |
|
Boron
Protons: 5
Neutrons: 6
Electrons: 5
Density: 2.08 g·cm−3 |
2. Define density and the equation for density and post on your blog.
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.
Density
Introduction: Density is a
physical property of matter that is calculated by dividing the mass of an
object by its volume. Volume can be
computed for a regular object by multiplying length x width x height. Another way to compute volume is by
submerging an object into a liquid. You
must record the starting volume of the liquid and the final volume after the
object has been submerged. Then subtract
the starting volume from the final volume.
Procedure:
- Open the
internet browser and enter the address: http://phet.colorado.edu
- Click on
“Play with Sims” and select “Chemistry” from the menu on the left.
- Open the “Density”
Simulation and select “Run Now”
Objectives:
- Describe how
the concept of density relates to an object's mass and volume.
- Explain how
objects of similar mass can have differing volume, and how objects of
similar volume can have differing mass.
- Measure the
volume of an object by observing the amount of fluid it displaces.
- Identify an
unknown material by calculating its density and comparing to a table of
known densities.
Investigate:
1.
On the Blocks menu (top right) select Same
Mass.
2.
One
at a time, take a block, lower it into the liquid, and record its volume. If it floats, you will need to hold it under
the water to record its volume. Then
compute each block’s density.
Blue:
mass:5 kg =1.0 kg/L
volume:5 L
Yellow
mass: 5kg=0.5 kg/L
Volume: 10 L
Green
mass : 5=2
kg/L
Volume: 2.50
Red
mass: 5=4.0 kg/L
Volume: 1.25
L
3.
Repeat
for Same Volume.
Blue:
mass: 6 kg = 1.2 kg/L
volume
5 L
Yellow
mass: 6 kg= 1.6 kg/L
volume: 5 L
Green
mass: 4 kg= 0.8 kg/L
volume: 5 L
Red
mass: 2kg= 0.4 kg/L
volume: 5 L
4.
Repeat
for Same Density
Blue:
mass: 3kg=0.8kg/L
volume: 3.75 L
Yellow
mass: 4 kg=0.8kg/L
volume: 5 L
Green
mass: 2 kg=0.8kg/L
volume: 2.5L
Red
mass: 1kg=0.8kg/L
Volume: 1.25L
5.
Repeat
for Mystery. This time you will also have to take the mass of each
object. After computing the density, select Show Table and identify each object.
A: Blue
mass:0.64kg=0.64 kg/L APPLE
volume:1L
B : Yellow
mass: 65.14kg=19.27kg/L GOLD
volume: 3.38 L
C :Green
mass: 4.08kg=0.70kg/L GASOLINE
volume: 5.83 L
D : Red
mass: 3.10kg=0.92kg/L ICE
Volume: 3.38 L
E:Purple
mass: 3.53kg =3.53kg/L DIAMOND
Volume: 1 L
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.
5. Identify and post on your blog the Science Standards that could be met through these activities completed in Activity 5
A.4.2
When faced with a science-related problem, decide what evidence,
models, or explanations previously studied can be used to better
understand what is happening now
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