Unit 2: What materials
are used in road construction?
F. Unit 2 Activities
Exploring Density
Test Demonstration
Introduction - This
activity will allow students to observe that
objects' level of suspension depends on the liquid's density and the
object's density.
Materials
Needed
3
clear plastic cups
tweezers or tongs
3 each of 5 different,
small objects (examples:
golf tees, erasers, popcorn
kernels, beads, toothpicks,
etc.)
rubbing alcohol
cooking oil
white corn syrup
paper and pencils for each student |
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Instructions
- The teacher should:
- Place the cups so they're
visible to all the students.
- Ask three students to
fill a cup with a different liquid.
- Starting with one set
of the small objects, such as golf tees,
and give one to each of the five students.
- Tell the class to watch
carefully.
- Then instruct the students
to drop the objects into the cups simultaneously.
TOP
Particle
Size Demonstration
Introduction -This
activity will give students the opportunity to
view materials as they are sorted by particle size.
Materials Needed
Clear tennis ball container
1/4-inch and 1/2-inch mesh hardware cloth (cut
in four-inch strips at
the store)
One-inch chicken wire (cut in four-inch strips at
the store)
sharp knife
scissors
duct tape (two-inch width)
four different-sized round objects (examples:
peppercorns, walnuts, navy beans, marbles)
wire cutters - may not be necessary if you have
the materials cut at the store
Note: the mesh hardware
cloth and chicken wire are standard sizes
and available at a hardware store.
Instructions:
The teacher should:
Step 1: Using the sharp
knife, cut the clear tennis ball can into four sections.
Step 2:
- Wrap duct tape around
the rim of the bottom section of the can. The tape should
extend one inch above the rim.
- Using the sharp knife,
cut one-inch slits in the duct tape down to the edge of the rim.
The slits should be 1 inch apart.
- The tape should be
peeled back like a banana.
- Working with one of
the 4-inch-square, 1/4-inch mesh pieces, center the piece over the
bottom section of the can. Set the 1-inch sections of tape
onto the screen to tape it in place.
Step 3:
- Repeat actions of Step
2 a, b and c around the top and the bottom edges of the first middle
section of the ball can.
- Place the bottom of
this section on top of the bottom section. Press the sections of
the duct tape onto the bottom to secure the two sections together.
Step 4:
- Repeating the same
procedures, connect the last two sections of the ball can.
Place the 1/2-inch mess square between the second and third sections.
Place the chicken wire between the third and fourth sections.
- Make sure you wrap
duct tape around the edge of each of the mesh and chicken
wire squares to make sure there the sharp edges have been covered.
Step 5: Fill the container
with a mixture of all four types of objects. It is suggested
that you use more of the small sized items and a few of the larger
items.
Step 6: Put the cap on
the container and you're ready for the demonstration.
Directions:
- Hold the container and
shake it.
- Notice the round objects
will fall through the container until they
hit a screen that the object is too large to fall through the openings
in that screen.
- There should be objects
sorted by size on all levels of the container.
- See what happens if you
turn the can upside down and shake it.
- Take the cap off the
can and take out the objects and replace them with different items
and see how these sort out!
TOP
Permeability
Test for Road Materials
Materials Needed
Rice Krispie Bars
candy bars - teacher's
choice (non-porous)
Directions:
Cut the Rice Krispie bars and candy bars into two-inch pieces.
Instructions:
The teacher should have:
Step 1: Students hold Rice Krispie bars in front
of their lips with their mouths slightly
open and
have them breathe out.
Observation
- Since the Rice Krispie bar is
permeable, the students will be able to feel
the air move out of their mouths, through the Rice Krispie
bars and to their hands.
Step 2: Students
hold pieces of candy bars in
from of their lips with their mouths slightly open
and have them breathe out.
Observation
- The students will not be able
to feel
the air move out of their mouths,
through the
candy bar and to their hands
because the candy
bar is non-porous and it
doesn't have any
holes in it like the Rice
Krispie bar.
TOP
Roadway
Cake
Introduction
- This activity
is designed to give students an opportunity
to build a roadway using the layer cake as a demonstration or model.
Materials
Needed
chocolate cake mix
egg(s)
1
can white frosting
cake plate
1 cup crushed Oreo cookies
water
round
cake pans
Directions -
Before the classroom
activity, the teacher should
follow the directions on the package to prepare the batter.
Pour the mix into two round cake pans. Follow the instructions
listed on the cake mix package for baking, cooling and removing
the cake from the pans.
Instructions -During
the classroom activity, the teacher will lead the students through the
assembly of the cake. The teacher will lead the discussion comparing
the layers of the cake to the layers of a roadway.
The bottom layer is
the subgrade. It supports the other layers.
Place one round cake in
the center of the cake plate.
The middle layer is
the base. The base is a mixture of crushed rock.
Spread the crushed cookies
on top of the subgrade cake.
The top layer is the
pavement. The pavement is the material on top of the roadway.
Place the second round
cake on top of the base.
To finish the activity,
frost the roadway cake.
Tell the students that
the frosting is similar to rain, frost, sleet and snow that sometimes
covers roads.
TOP
Stress
Test Demonstration
Introduction
- Students will compare
the strength needed to break
each plastic strip. Students could use this stress test to compare
different brands of trash bags, grocery bags, and other plastic
materials.
Materials Needed
plastic freezer bag
plastic food wrap
microwave wrap
trash bags
grocery bags
other similar plastic products
template (provided at the end of this page)
scissors
Directions -
Students should:
- Use the template provided
at the end of this page to
cut approximately 2.5cm by 12cm strips from the
plastic freezer bag.
- Slowly pull the ends
of the strips (stress), and feel
the resistance of the plastic material (strain).
Template -
When using the template
to cut plastic materials, be sure
to hold the plastic to the light to see the direction of the grain
(extrusion polymer chains) lines. Cut the bars parallel or antiparallel
to the grain.
Tensile Bar Template
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