How does motor oil affect the preferences of earthworms?
Josh Otte
7-2
Voelker
3/4/16
Abstract
In this experiment the scientists are trying to figure out if worms prefer soil with
motor oil or moist soil. The scientists wanted to know this because if a car spills oil, and this oil
leaked into the soil will the worms that are living in the soil like the oil or not. The scientists
investigated this by putting an earthworm in a tray where one side was soil with oil and the other
side was moist soil. The scientists recorded how many times the earthworms touched the oil,
and how many times it touched the moist soil side. The scientists also recorded observations.
The scientists finally concluded that the earthworms like the side with moist soil oil more than
the side with oil. The scientists know this because even though the earthworm touched the side
with oil, whenever the earthworm did it quickly spun away. Also when the earthworm touched
the side with oil it never tried to burrow like it did when it touched the moist soil side. The
scientists know the worms liked the moist soil because when they touched it they never spun
away and they did try to burrow in it. This information is relevant because now the scientists
know that earthworms do not prefer oil over moist soil and they do not like to burrow in it.
People all over the world now need to help keep oil out of the soil because the earthworms do
not like it and do not like to burrow in it. If the earthworms do not burrow in the soil they can or
will die.
Introduction
The scientists in this experiment decided to test the effects of motor oil on earthworms. If
a car has a leak and spills some motor oil and it gets absorbed by the soil will this affect
earthworms? This will be important because then the scientists will know if our oil leaks are
affecting the earthworms under the soil.
It is already known that oil causes harm to our soil, such as: entering our water systems
causing our drinking water to be contaminated, and making the soil too toxic to support the life
of growing plants.
A study was recently done by Kavitha Ramadass to test the affects of how earthworms
are affected by used oil and non-used oil. Kavitha Ramadass found that the worms were
affected more by the used oil than the non-used oil. She believes this because when the oil has
been used it is exposed to more toxic material and metals than brand new oil. This shows the
scientist’s that oil is already known to cause some harm to earthworms but we want to know if
they prefer it or not. Kavitha’s research also made the scientist’s expectation of the earthworms
not liking the motor oil more likely.
The first experiment the scientists conducted was putting earthworms in soil with
different amounts of oil such as 20mL, 40mL and 60mL. The control variable was the moist soil.
The scientists left the earthworms in the soil overnight. The next day the scientists were
planning to test the burrowing times of the earthworms because the earthworms were already
exposed to the motor oil. The purpose of this was to see if the motor oil affected the
earthworm's movement. The scientists were surprised to see that the next day all of the
earthworms were dead.
The scientists were expecting the worms, (especially the ones with higher amounts of
oil) to have slower burrowing time and limited movement. This was not the data the scientists
were looking for so the scientists had to conduct another experiment since all of the worms died.
That is why the scientists conducted a second experiment to see if earthworms preferred
soil with motor oil or just moist soil. Some of the research the scientists had to do for this
included on average, how much motor oil spills from a car when it has a leak. This is useful
information because the scientist then knows about how much oil to use. The scientists found
that most cars use 2 gallons of motor oil which would be to much for the experiment so the
scientists reduced it down proportionally according to the size of the container they were using.
The scientists also needed to know how much soil will be affected by this oil spill and
how many worms will be in that area and affected. The scientists found that just one quart of oil
it can pollute 40,730 square feet of earth.
In this experiment the scientists were expecting the worms to prefer the moist soil rather
than the soil with oil. They expected this because motor oil is a lot thicker than water and will be
harder for them to burrow in and the oil will also feel a lot different on their bodies that water.
The motor oil also contains many chemicals that the worms should not like.
Materials/Methods
The materials needed for this experiment include one dissecting tray, 500 mL of moist
soil, 75 mL of motor oil, a spray bottle with water, safety goggles, gloves, something to record
data with, a stopwatch, and at least 3 earthworms.
One of the safety precautions scientists should observe is wearing safety goggles to
avoid getting motor oil in their eyes. Gloves are highly advised to be worn by the scientists when
dealing with the oil to prevent skin irritation.
The first thing the scientist will do is put on safety goggles and gloves so no oil gets in
the scientist's eyes or on their hands. Then the scientist will then take the dissecting tray and
put 250 mL of moist soil on each side leaving a “runway” in the middle with no dirt for the
earthworm. The soil on the left side will contain the motor oil while the side on the right with be
just moist soil. Then the scientist will slowly pour the 75 mL of motor oil on the left side making
sure to get none on the right side. Make sure the motor oil soaks into the bottom of the soil and
does not just sit on the top. Then the scientist will take spray bottle and spray the right side to
ensure the soil is moist enough. Make sure there is no soil in the “runway”. Next the scientist will
place the earthworm in the “runway” for five minutes. During this five minutes the scientist
should record if the earthworm preferred the oil side or the moist side. The scientist should also
record things the worm did such as did the worm try to burrow on the oil side or did it just touch
it and then backed away also known as observations. Finally the scientist should record how
many times the earthworm touched the oil side and how many times it touched the moist side.
The scientist can record the data in a notebook with observations for each worm. The scientist
can also use a spreadsheet to record data and then put it into a graph. The scientist should
repeat this process with at least 3 earthworms, the scientists in this experiment used 4
earthworms.
Results
In this experiment the scientists are trying to conclude if earthworms prefer soil with oil in
it or just soil with water. The scientists did this by seeing if the earthworm would chose soil with
oil or soil with water. The scientists put the earthworms in a tray with soil with water on one side
and soil with motor oil on the other. The scientists then counted how many times the
earthworms touched either side and any observations such as if the worm tried to burrow. The
reason the scientists did this is to see if motor oil harms earthworms and if they like it or not.
This is useful because sometime cars have motor oil leaks, what if this oil runs into the soil. Do
the earthworms like this or not?
Motor oil is a liquid used to help engines operate correctly. Even though motor oil helps
engines run correctly, it has many chemicals in it such as, benzene, lead, magnesium,
chromium, arsenic, zinc, and cadmium. The scientists also new from Kavitha’s experiment that
motor oil is harmful to the soil. What the scientists didn’t know is if earthworms like motor oil.
All cars need motor oil to run efficiently, but what happens if this car has a leak. If the
motor oil from this car leaks into the soil will the earthworms living in it like it or not? The
scientists were expecting the worms to prefer the moist soil rather than the soil with oil. The
scientists were expecting this because motor oil is a lot thicker than water and will be harder for
them to burrow in and the oil will also feel a lot different on their bodies that water.
After completing the experiment the scientists were able to conclude that the worms
prefered the soil with water rather than the soil with oil. The scientists were able to conclude this
because of the amount of touches and the observations. Although the earthworms kept touching
the side with the motor oil, the scientists could tell they did not like it. Whenever their heads
touched it they quickly spun away. In addition whenever the earthworms touched the side with
the oil they never tried to burrow it unlike when they touched the side with water they attempted
to burrow and didn’t spin away. The earthworms liked the side with water because they did try to
burrow in it several times and they crawled on it unlike the motor oil side.
The independent variable in this experiment was the oil. The dependent variable is how
many times the worms touched the soil with oil and how many times the worms touched moist
soil because the scientists can measure this. The control variable was the moist soil because
the scientists kept this the same unlike the scientists could change the amount of motor oil.
In the graph below you can see on the y axis that we have the number of touches and
on the x axis we had the worm number. The bars in blue are the times that the worm touched
the soil with motor oil. The bars in red are the times the worm touched the side with moist soil.
In the graph you can see that worm 1 touched the motor oil 10 times and moist soil 13 times.
Worm 2 touched the motor oil 4 times and the soil 6 times. Worm 3 touched the motor oil 7
times and the soil 3 times. Worm 4 touched the motor oil 5 times and the soil 3 times.
During the experiment the scientists also recorded observations. Worm 1 didn't like the
motor oil. Whenever it touched the oil with its head it quickly spun away. The worm never tried
to burrow in the soil with motor oil, but it did touch it several times. When the worm touched the
moist soil it did not spin away. The worm also tried to burrow in the moist soil unlike the soil with
oil. Worm 2 preferred the moist soil more that the soil with the motor oil. This was discovered
because the worm never burrowed in the soil with the motor oil but it did try to burrow in the
moist soil. Worm 2 had that same reaction as worm 1 to the motor oil, whenever it touched the
soil with oil it quickly spun away. Worm 3 didn’t seem to care whether he was on the soil with
motor oil or the moist soil. He would touch both of the types of soil with no reaction. This worm
didn’t try to burrow in either type of the soil it just went on top of it. Worm 4 touched the motor oil
but then quickly spun away. The worm never tried to burrow in the motor oil. The worm liked the
moist soil and even tried to burrow in it one time.
The scientists can conclude that even though the worm touched the soil with motor oil
whenever it did it quickly spun away. In addition whenever the worm touched the side with oil it
never tried to burrow in it. The scientists know the worms liked the moist soil because when they
touched it they never spun away and they did try to burrow in it.
Discussion
The scientists thesis was to conclude whether earthworms preferred soil with oil or moist
soil. This is useful because if a car leaks oil and this oil seeps into the soil will the earthworms
living in the soil like the oil or not? The scientists found that worms prefer moist soil over soil
with motor oil.
The scientists results conclude that the earthworms prefer moist soil. The scientists
know that even though the worm touched the soil with motor oil whenever it did it quickly spun
away. In addition whenever the worm touched the side with motor oil it never tried to burrow in
it. The scientists know the worms liked the moist soil because when they touched it they never
spun away and they did try to burrow in it.
The scientists results are meaningful because if motor oil is leaked into our soil the
earthworms will not burrow in it. If the earthworms don’t burrow in the soil, they can or will die.
This is why motor oil leaking from cars is such a big problem.
Some human error that could of occurred is that the scientists might of miscounted the
amount of touches. Also the scientists might have gotten worms that were not as active or dying
which might have caused the amount of touches to be down or maybe it would not burrow.
The reason the earthworms preferred the most soil over the soil with motor oil has to do
with Kavitha’s experiment. She found that worms are affected by both used and unused oil.
Both of the oil types caused the worms to be affected.
The scientists found on Oil’N’Go that motor oil is a lot thicker than water. This will cause
the earthworms to have a harder time burrowing in the motor oil than the moist soil because the
motor oil is a lot thicker. The scientists also found that motor oil has hundreds of toxic chemicals
in it. This is what caused the worms to spin away whenever they touched the motor oil. Kavitha
found that these chemicals are harmful to the earthworm's skin.
An experiment the scientists could try later would be to test burrowing time. The
scientists tried this experiment first but the worms died. The scientists could maybe try using
less oil because maybe that's what caused the worms to die. If the scientists tested burrowing
time they could then conclude if worms burrowed better in motor oil or if they burrowed slower.
The scientists could also conclude if motor oil affected the earthworm’s movement when
burrowing.
Appendix
Sources:
"All About Oil." All About Motor Oil. N.p., n.d. Web. 24 Jan. 2016.
http://www.calsci.com/motorcycleinfo/Oils1.html
"Does Neem Oil Harm Earthworms?" Does Neem Oil Harm Earthworms? N.p., n.d.
Web. 24 Jan. 2016.
http://www.discoverneem.com/neem-earthworms.html
"Ecological Implications of Motor Oil Pollution: Earthworm Survival and Soil
Health." ResearchGate. N.p., n.d. Web. 24 Jan. 2016.
https://www.researchgate.net/publication/273898087_Ecological_implications_of_motor_oil_poll
ution_Earthworm_survival_and_soil_health
"Oil N Go." Oil N Go. N.p., n.d. Web. 24 Jan. 2016.
http://www.oilngo.com/usedoil.html
"What Are the Effects of Used Engine Oil on Soil?" Garden and Flowers. N.p., n.d. Web.
24 Jan. 2016.
http://www.gardenandflowers.com/list_7672799_effects-used-engine-oil-soil.html
Here is a picture of the two trays the scientists used for the experiment. In each tray the
soil on top has motor oil and on the bottom is the moist soil.
This is an image of the worm when the scientists were observing which side it touched.
This is an image of when the worm touched the side with motor oil but then turned away.