Respiration Experiment Lab Report

Respiration Experiment

Purpose

Our purpose is to prove the concept that we breathe in oxygen and emit carbon dioxide. Also to prove that living things do respiration and non-living things don’t. We are also doing this experiment because cellular respiration allows our body to properly function and maintain homeostasis.

Hypothesis

I think that the living peas will do more respiration than the dead peas because homeostasis requires oxygen through respiration but dead things do not.

Apparatus

l  Peas

l  Dry Cotton Wools

l  Potassium Hydroxide (KOH)

l  Rubber Stoppers

l  Ink or Food Coloring

l  3 glass boiling tubes

l  3 rubber tubes

l  Ruler

l  Tweezers

l  Dropper

l  Tongue

l  Sponge

l  Sink

Procedure

  1. Fill up the sink with water about 7-8 cm from the bottom.
  2. Put living peas into 2 glass boiling tubes with the same amount
  3. Put small paper balls into another glass boiling tube.
  4. Put a boiling tube with living peas into the microwave to make it dies.
  5. Put a dry cotton wool in each boiling tubes.
  6. Make a saturated solution of KHO and water.
  7. Wet 3 cotton wools with KHO
  8. Put a wet cotton wool with KHO in each boiling tubes.
  9. Seal with rubber stoppers immediately
  10. Put a drop of ink on the top of each rubber tubes, and hold the end of the rubber tube.
  11. Submerge the boiling tubes in the sink of water, and wait until the ink stops moving, and make sure that these tubes don’t float up by using heavy things such as wet sponge to keep them submerged
  12. When the ink stops moving, record the starting point, and start timing for 5 minutes.
  13. After 5 minutes, we mark the ending point, and measure from starting point to end point.

Results

  Total Distance Moved Rate of Movement
Living Peas 3cm 0.01cm/sec
Dead Peas 2cm 0.007cm/sec
Paper Balls 0cm 0cm/sec

Conclusion

My hypothesis was correct because the ink blob in the tube of the living peas moved more than the ink blob than the dead peas. The ink blob moved because the living peas did respiration and emitted carbon dioxide. Then the CO2 was sucked out of the air by the cotton wool soaked in KOH stuck in the boiling tube, creating a vacuum due to the disappearance of CO2 in the atmosphere of the boiling tube. Therefore, causing the ink blob in the plastic tube to move inwards by quite a margin while the dead peas moved only a little bit. The reason behind this was that Oxygen is required in homeostasis causing respiration while the dead peas did not require the oxygen so they did not respire. Also we can conclude that there was no movement what so ever in the boiling tube containing the paperballs because paper balls are non-living things that are not even made up of cells. It could be observed throughout the experiment that as soon as we made the KOH solution it would get cloudy and the temperature would rise when the solution started taking CO2 out of the air. Also we didn’t get the results of the dead peas not respiring at all like the theory states. This is because we didn’t completely kill the peas but only killed around 30% of them and stressed the other 70% therefore maybe causing quite a bit of respiration to happen because stressed plants do more respiration. Therefore, we have concluded that the peas alive did more respiration than the dead peas, and that the paper balls did none. Also that the dead peas control was flawed due to the fact that we didn’t completely kill all the peas in the boiling tube.

Analysis

My experiment had results that were consistent with the other groups but they were no perfect. All of my measurements had human errors. I used my human eyes and the clock on the wall instead of a stopwatch therefore I might have made an error calculating 5 minutes correctly. Also I measure the movement in the ink using a ruler that only went to the first decimal place of centimeters. Other errors in calculations may have occurred when I was measuring the movement in the plastic tube because I used a straight rigid ruler on a curved tube. When we were adding ink to the plastic tubes I made an error on how much I put since it differed a bit for each. Sometimes it was 2 drops, sometimes one, or sometimes as much as I could. Next time I do the experiment I would put the peas in the microwave for a longer time so we completely kill the peas in the dead peas tube. Our experiment was also one against time because the KOH would be classified in the state of not being able to use because it would start its reaction with CO2 in the atmosphere right away

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