Science Essay Research Paper Materials and MethodsThe

Science Essay, Research Paper

Materials and Methods

The first experiment involved examining the effect of temperature on aerobic

respiration of germinated pea seeds. The students testing the effect of temperature, will

be divided into two groups. The first group is Student Pair A. They will test the effect of

10C, 20C and 30C temperatures on pea respiration rate. The second group is Student Pair

B. They will test the effect of 40C and 70C temperatures on pea respiration rate. For both

groups, the first procedure calls for writing down a hypothesis to the effects of

temperature on the respiration rate of germinated pea seeds. There are two parts to the

first experiment, the making of an experimental tube and the making of a control tube.

For the experimental tube, you must select 20 pea seeds and place them in a beaker filled

with cold tap water that you will get from the sink. The pea seeds will soak for 2 minutes.

After the 2 minutes are completed you will need to remove the seedcoat from the pea

seed. The seed coat is the thick light-green colored covering of the seed. You will be able

to remove the seedcoat easily if the pea seeds were soaked for the 2 minutes. After

removing the seedcoat, fill two plastic capsules with fresh lime soda. Take an

experimental test tube and place the 20 germinated pea seeds in it. The pea seeds should

almost fill the test tube. Place one of the lime soda capsules on top of the pea seeds in the

experimental test tube. Take a cork stopper and enclose the pea seeds and the lime soda

in the experimental tube. For the control tube, take 20 beads and place them in the test

tube. The beads should almost fill the test tube. Place the soda lime capsule in the test

tube. It should lay on top of the beads already in the test tube. The space taken up by the

beads in the control tube should be the same space taken up by the pea seeds in the

experimental tube. Remove the pea seeds and the soda lime capsule from the

experimental tube. Take all 20 of the pea seeds and weigh them together on the scale.

Weigh the pea seeds to the nearest 0.1g. Record their weight in Table 1. Set the pea seeds

that was weighed to the side , making sure that they are not agitated. These peas seeds are

the experimental peas and will be used for the remainder of the experiment. For the

control tube, remove the beads and the lime soda capsule. You will not need to weigh nor

record data as in the experimental tube.

Student Pair A procedure is to soak the 20 peas and the 20 beads for 10 minutes

in 10C tap water. The tap water will not be 10C, so you must add small amounts of ice to

the tap water. They must be soaked in water so that they can get gas. Measure the tap

water with a thermometer, making sure that it is 10C during the entire time the pea seeds

and the beads are soaking. After the water is prepared, fill the manometer water bath to

the top with 10C tap water. The manometer water bath is a round container with a

covering that has two small holes at the top. The covering allows test tubes to be placed

in it. Place the covering on top of the manometer bath water. Insert the experimental and

the control test tubes into the holes of the cover. Make sure that you hold the manometer

bath water with two hands on the base because if you hold it from the rim, it will break.

During the 10 minutes check the temperature of the water bath, making sure that it is

10C. If it warms up, add a few pieces of ice to get the temperature to 10C. When the ten

minutes are up, drain the peas and beads. Blot them dry very carefully with a towel. Take

the experimental and the control tubes out of the water bath. Quickly transfer the peas

into the experimental test tube and the beads into the control test tube, that are in the 10C

water bath. Place the soda lime capsules in each one of the test tubes. The soda lime

capsules remove carbon dioxide from the tube so that you can get an accurate response of

how much oxygen that the organisms are breathing Place the cork stopper tightly on the

experimental and the control tubes, using the rubber stopper and the t-rigs. Place the two

test tubes into the water bath and connect the plastic tubes of each of the t-rigs to the

metal connectors of the manometer block. Make sure that they are tightly secured but do

not force the plastic tubes all the way to the metal connectors. Allow the test tubes to set

for 5 minutes. Set the experimental syringe at 1.0cc and the control syringe at 1.0cc.

Close the experiment by close shut the rubber escape tubes of both t-rigs using metal

clamps. The metal clamps should be placed at the middle of the escape tubes so that

there is a less possibility that air will escape. They should be closed at the same time.

Adjust the manometer fluid with the syringe attached to the t-rig. The height should be

equal on both sides of the U-tube. Take a wax pencil and mark the level of the

manometer fluid. In table 1 record the setting of the experimental syringe and the time.

After every two minutes re-level the manometer fluid back to the starting level, that you

marked off with the wax pencil. You can do this by depressing the syringe plunger on the

experimental t-rig. Record the results on table 1. This should be done for 12 minutes. The

difference of the experimental syringe reading after leveling the manometer fluid and

that after 2 minutes is the amount of oxygen that was consumed by the peas. After the 12

minutes are completed and the 2 minute results are recorded, open the experiment by

removing the metal clamps from the escape tubes. Make sure that manometer fluid does

not move into the brass connectors are the t-rigs, when removing the metal clamps. If this

should happen. clean it out using pipe cleaners before proceeding with the next

experiments. For the 20C and the30C experiment you will repeat all the steps. This time,

you will need to fill the manometer bath with 20c and 30C water. Always check the

temperature with a thermometer, so that it will remain constant.

The procedure for Student Pair B begins by soaking the 20 peas and the 20 beads in

40C tap water for 10 minutes. Make sure that the water stays at the 40C temperature by

periodically checking it with a thermometer. While the peas are soaking, fill the

manometer water bath to the top with 40C tap water. Place the cover over the water bath

and then insert two test tubes through the holes of the cover and into the 40C tap water.

This will keep the test tubes warm. Check the temperature of the water bath before the 10

minutes are complete. After soaking for 10 minutes, drain the 20 pea seeds and the 20

beads. Take the experimental and the control test tubes out of the 40C after bath and

quickly transfer the pea seeds in the experimental test-tube and the beads in the control

test tube. Place the soda lime capsule in each of the experimental and control test tubes.

Tightly place the rubber stopper with attached T-rigs on each on the test tubes. Place the

test tubes into the 40C manometer water bath and connect the plastic tubing of each T-rig

to the metal connectors of the manometer block. Make sure that you do not force the

plastic tubes all the way to the metal connectors. Allow the test tubes to stay in the 40C

bath water for 5 minutes. Set the experimental syringe at 1.0cc and the control syringe at

0.5cc. Place the metal clamps in the middle of the robber escape tubes, so that air will

not be able to escape. Using the syringe attached to the control T-rig, adjust the

manometer fluid so that it is equal height on both sides of the U-tube. Mark the level with

a wax pencil. In table 1, record the setting of the experimental syringe and the time. After

2 minutes, re-level the manometer fluid to its starting level by depressing the syringe

plunger on the experimental T-rig. In table 1 record the new reading on the experimental

syringe. Start timing the reaction for another 2 minutes. This should be done for a total of

12 minutes. You should have a total of 6 results. In the procedure for 70C temperature,

take a metal pan and place a dry paper towel in it. Write your initials on the paper towel

so that you will be able to identify your pan. Take the experimental tube and the control

tube and empty the contents into the metal pan. Dry the test tubes that was just emptied

and place them into the same metal pan. Place the pan into the 70C drying oven. Let it set

in the oven for 15 minutes. While the pan is setting in the oven, set up a 70C water bath.

Place hot water on to a hot plate to bring the temperature up to 70C. Fill the water bath

with hot tap water and the water that was on the hot plate. Check the temperature with a

thermometer to make sure that the water is 70 C. When the 15 minutes are completed

take the metal pan out of the oven using hot pads. If the tubes are not completely dry take

a small paper towel, roll it up, and clean out the test tubes. Place the 20 peas in the dry

experimental tube and the 20 beads in the dry control tube. Place a soda lime capsule in

each of the test tubes. Put the experimental and the control tubes into the water bath and

place the T-rig assembly without the metal clamps on each test tube. Let the test tubes set

in the 70C water bath for 10 minutes. After the 10 minutes are complete, close the system

with the metal clamps. Take 6, 2 minute readings of the respiration. Record them in table

The second experiment involved examining the effects of temperature on

mealworm respiration rate. The students are divided into 2 groups: Student Pair A and

Student Pair B. The Student Pair A examined the effect of 10C, 20C, and 30C

temperatures on mealworm respiration. Student Pair B examined the effect of 40C and

55C temperatures on mealworm respiration. Both groups are to write down their

hypothesis as to the effects of temperature on the respiration rate of the mealworm

larvae, based on their knowledge of aerobic respiration. Select 20 mealworms from the

culture. Weigh the mealworms on a gram scale and measure them to the nearest 0.1g.

Record the weight of worms in Table 3 under the Student A or Student B, depending on

your classified group. Fill 2 plastic capsules with fresh lime soda. Gently place the worms

into the experimental test tube with twizzers. Place a small cotton plug 3/4 up the tubes

so the mealworms are not able to grab it. Place one of the lime soda capsules on top of

the cotton plug in the experimental test tube. Break toothpicks into small pieces and

place them into the bottom of the control test tube. Place a cotton plug on top of the

pieces of tooth picks and also place the other soda lime capsule on the test tube. It should

be lying on top of the cotton plug. The control tube and the experimental tube should

take up the same amount of space, so compare the two. Tightly stopper the experimental

and the control tubes using the rubber stoppers with attached T-rigs.

The procedure for Student Pair A starts by filling the manometer bath water to the

top with 10C tap water. Lower the experimental and control tubes into the 10C

manometer water bath and connect the plastic tubing of each T-rig to the metal

connectors of the manometer block. Let the tubes set for 15 minutes in the manometer

bath water. Set the experimental syringe at 1.0cc and the control syringe at 0.5cc. Close

the experiment by placing the metal clamps over the middle of the rubber escape tubes.

Use the syringe attached to the control T-rig and adjust the manometer fluid so that it is

equal height on both sides of the U-tube and mark the level with a wax pencil. Record the

setting on the experimental syringe and the time in Table 3. Read the changes in the

experimental syringe at 2 minute intervals for 12 minutes. You will have 6 readings. Rate

the activity of mealworms during the experiment. Rate them with 0= no movement,

+=slow movement, ++=moderate movement, or +++=rapid movement. Record the

observations in the last column of Table 3. After the measurements are completed at

10C, remove the metal clamps from the escape tubes. Repeat the steps for the

temperatures of 20C and 30C. Adjust the temperature of the bath water very carefully.

Allow the experiment to set for 15 minutes before closing the escape tubes and taking the

readings. Take 6 readings for each of the temperatures. Readings should be made every 2

minutes but at 30C it could be taken at every 1 minute.

The procedure for Student Pair B starts by filling the water bath to the top with

40C. Lower the experimental and control tubes into the 40C manometer water bath and

connect the plastic tubing of each t-rig to the metal connectors of the manometer blocks.

Allow the experiment to stay for 15 minutes. Set the experimental syringe at 1.0cc and

the control at 0.5cc. Close the experiment by placing the metal clamps on the rubber

escape tubes on both of the T-rigs. Adjust the manometer fluid so that it is equal height

on both sides of the U-tube and mark the level with a wax pencil. Record the setting on

the experimental syringe and the time in Table 3. After 1 minute re-level the manometer

fluid to its starting level, which should be marked by the wax pencil. In table 3 record the

new reading on experimental syringe and start timing the reaction for another minute.

The difference of the two readings on the experimental syringe represents the amount of

oxygen consumed by the meal worms. The recording should be in cc. Read the changes

every 1 minute for 6 minutes. Rate the activity of the meal worms and record in the last

column of table 3. For the procedure at 55C, line a metal pan with a damp towel. Place

the contents of the experimental and the control tube into the pan. Take a paper towel

and dry the inside and outside of the test tubes and place them in the metal pan. Place the

pan in the 55C drying oven and allow it to stay in there for 15 minutes. While the pan is

in the oven, prepare a water bath with 55C temperature. When the 15 minutes are

complete, remove the pan from the oven using hot pads. Place the mealworms, cotton,

and soda lime capsule into the experimental tube and place the toothpicks, cotton, and

soda lime into the control tube. Place the experimental and the control tube into the water

bath and put the t-rig assembly on each tube. Let the test tubes to set in the water for 10

minutes. Set the experimental syringe at 1.0cc and the control syringe at 0.5cc. Take the

metal clamps and close the rubber escape tubes of both t-rigs in the middle of the escape

tubes. Adjust the manometer fluid so that it is equal height on both sides of the U-tube

and mark the level with a wax pencil. Record the setting on the experimental syringe and

the time in Table 3. Record it in cc. After 1 minute, re-level the manometer fluid to its

starting place by depressing the syringe plunger on the experimental t-rig. Record the

new reading on the experimental syringe and start timing the reaction for another 1

minute. This should be done every minute for 6 minutes. There should be 6 recordings.