Experimental And The Control Test Tubes example essay topic

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 10 C, 20 C and 30 C temperatures on pea respiration rate. The second group is Student Pair B. They will test the effect of 40 C and 70 C 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 b 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 0.1 g. 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 10 C tap water. The tap water will not be 10 C, 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 10 C 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 10 C 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 10 C. If it warms up, add a few pieces of ice to get the temperature to 10 C. 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 10 C 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 1.0 cc and the control syringe at 1.0 cc. 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 20 C and the 30 C experiment you will repeat all the steps. This time, you will need to fill the manometer bath with 20 c and 30 C 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 40 C tap water for 10 minutes. Make sure that the water stays at the 40 C temperature by periodically checking it with a thermometer. While the peas are soaking, fill the manometer water bath to the top with 40 C tap water. Place the cover over the water bath and then insert two test tubes through the holes of the cover and into the 40 C 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 40 C 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 40 C 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 40 C bath water for 5 minutes. Set the experimental syringe at 1.0 cc and the control syringe at 0.5 cc. 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. 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 70 C 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 70 C drying oven. Let it set in the oven for 15 minutes. While the pan is setting in the oven, set up a 70 C water bath. Place hot water on to a hot plate to bring the temperature up to 70 C. 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 70 C 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 1. 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 10 C, 20 C, and 30 C temperatures on mealworm respiration. Student Pair B examined the effect of 40 C and 55 C 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 0.1 g. 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 10 C tap water. Lower the experimental and control tubes into the 10 C 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. 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 10 C, remove the metal clamps from the escape tubes.

Repeat the steps for the temperatures of 20 C and 30 C. 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 30 C it could be taken at every 1 minute. The procedure for Student Pair B starts by filling the water bath to the top with 40 C. Lower the experimental and control tubes into the 40 C 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 1.0 cc and the control at 0.5 cc. 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. 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 55 C, 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 55 C drying oven and allow it to stay in there for 15 minutes. While the pan is in the oven, prepare a water bath with 55 C 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. Take the metal clamps and close the rubber escape tubes of both t-rigs in the middle of the escape tubes. 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. 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. Record them in table 1.

Record it in cc.