Name:_____________________ Date:___________ Period:_____
Lab - Rate of Weathering
Introduction:
The most important factors that affect the rate at which weathering occurs are
climate, type of rock and particle size. Of those three, climate is the most important.
Some rocks weather easily because they are permeable. Permeable means that a material
is full of tiny, connected air spaces called pores that allow water to seep in.
Permeable rock weathers chemically at a fast rate. Weathering can only affect
exposed surfaces. Since a given volume of small particles have a larger surface area than
the same volume of large particles, small particles tend to weather faster.
Vocabulary:
Mechanical Weathering –
Abrasion –
Chemical Weathering –
Erosion –
Deposition –
Climate –
Sediment –
Permeable –
Surface area –
Procedure:
Part 1 – abrasion of sugar cubes
1. Place 2 sugar cubes in a plastic cup and cover the cup with another plastic cup. Tape
them together.
2. Shake for a few minutes until you see changes occurring. 3. Open up the cups and fill in
the data table.
Part 2 – sugar with vinegar
1. Add 25 ml of water and 25 ml of vinegar to the beaker.
2. Add 1 sugar cube and stir. Record the time it takes for the sugar to
dissolve. If it exceeds 5 minutes then write >5 in the data table.
3. Add one teaspoon of granulated sugar. Record the time it takes for them to
dissolve.
Part 3 – Alka-Seltzer
1. Fill up the beaker with 50 ml of water.
2. Drop one Alka-Seltzer tablet in the water and record the time it takes for
it to dissolve. Be careful – this is quick!
3. Fill up the beaker again with 50 ml of water.
4. Crush the other Alka-Seltzer tablet and drop it in the water. Record the
time it takes to dissolve. This is really quick!
Data:
Part 1 – Abrasion of Sugar
Sugar Cubes Before Sugar Cubes After
Observations
Sketch
Part 2 – Sugar with vinegar
Sugar Cube
Time to dissolve
1 sugar cube
1 tsp granulated sugar
Part 3 - Alka-Seltzer
Sugar Cube
Time to dissolve
1 whole tablet
1 crushed tablet
Analysis Questions:
1. What happened to the shape of the cubes in part 1?
2. In part 2, which dissolved faster and why? 3. In part 3, which dissolved faster and why?
4. What kind of weathering was occurring when the sugar was being broken in half? Why?
5. What kind of weathering was occurring when the sugar was being dissolved? Why?
6. Classify the following examples as either physical (mechanical) weathering or
chemical weathering.
a. ____________________ Cracks appear in a sidewalk next to a large tree.
b._____________________ A piece of limestone develops holes.
c._____________________ A rock exposed at the surface slowly turns reddish brown.
7. Suppose physical weathering breaks rocks into pieces. How would this affect the rate at
which a rock weathers chemically?
8. Minerals that make up rocks determine how fast the rock weathers. What would happen
if a rock is made up of minerals that are resistant to weathering?
9. Why would a permeable rock weather at a faster rate?
Conclusion:
On the Moon, there is no air or water. Explain if weathering would occur. Why or why not?