7. Repeat numbers 2 to 5.
8. Repeat 6, making sure the pappus will
look like the diagram on the right once
you have cut a quarter of it each time
9. Record results
Fair Test:
In order to make this experiment a fair test, you will have to:
1. Make sure that you only use ONE seed, otherwise the reading will be faulty if you use a different seed during the experiment
2. Drop the seed at the same point from the meter stick.
From the diagram on the right, you can see the two
places on the meter stick where you can drop the
seed from. If you start by dropping it from one
place, DO NOT drop it from the other place, otherwise
the readings will be unfair
3. Cut ONE QUARTER of pappus each time
because the readings will be useless if you cut
one quarter of the pappus, and then cut a fifth afterwards.
4. Double-check all of your calculations. This is just to double check and see if the answer is right
Safe Test:
In order to make the experiment a safe one, you will have to double check and see if the meter stick is firmly in place, because there is the risk of it falling down, and hitting someone. Apart from that, and the normal safety procedures, this experiment is very safe.
Observations
For my observation I got a set of results. I did the experiment twice for repetition to give me better results that are more accurate. All results were taken fairly with me not being bias, against any results or altering any of the results for any reason. All of my results were taken to the best of my ability to gather the most accurate results.
Results
My results consist of two tables of results one for each tragaponam pratensis (pappus).
Pappus 1
Pappus 2
These are the results I obtained from the experiment on the pappus. My readings were very difficult to take, as this experiment was a lot to do with my judgement, reflexes and accuracy. So if there is any inconsistency with the data then it is mainly due to human error.
I took my reading from the second the tragaponam pratensis left my hand at the top of the one metre stick (when I start the stop clock with my other hand) to when the pappus hits the table one metre later. The way I measured the size of the pappus was by drawing a rough trace of it on graph paper. Then I roughly worked how much half was, a quarter was etc. then I cut the pappus to size by use of scissors. So actually the diameter of the pappus was the size. As the area wasn’t exactly being reduce proportional.
Analysis
For my analysis I will try to represent the data in a more understandable form, so that I can analyse it. Also I will see what else I can find out with this data apart time taken for a pappus to fall a certain distance.
Some of the other things that I can work include speed, acceleration, average of all three times for each pappus etc. first of all I will find the average so I can use the average time to base my other calculations on.
I used simple formulae for these calculations it was
Sum of numbers
Average time = number of numbers
The second thing I would like to calculate is the speed. Dividing the average distance by the average speed does this.
I noticed that the most suitable speed unit for me to use would be metres per second. There is one more thing I could calculate that I mentioned it was acceleration it is calculated by using the formulae
Change in Velocity
Acceleration = time taken
I will know show all the results for the other pappus 2. It will have all the calculation as above but for another experiment so that I get more accurate result by repetition
Acceleration would always be 1.
From the graphs on the next three pages I have made some analysis. All the graphs are the graphs from the average results I got for each size of pappus. I have plotted the time taken for the pappus to fall against the size of the pappus and then the speed of the pappus to fall against the size of the pappus. There are 4 graphs, 1 for the time taken for each pappus to fall in experiment 1 against the size of the pappus, one for the speed of the pappus falling against the size of the pappus in experiment 1 and then the same two graphs for experiment 2. I found that graphs 1 and 2 for each experiment were identical after plotting them All the graphs have a positive correlation that means the bigger the size of the pappus the longer it stays in the air, which is a logical theory. There were some anomalous results but they were largely due to human error but it could have been because inaccurate equipment or any number of reasons.
Conclusion
My conclusion is that my prediction that was as the surface area of the pappus decreases the time it takes for it to fall will decrease as well. So my prediction was correct as is evident from the analysis and the results. My theory is the tragaponam pratensis has pappus for the reason of a safe land. And so the seed does not get damaged. This is so the seed will survive to grow and continue the species.
The readings proved to be the ones I suspected when I look at the graph. The graph showed an almost straight line going down in the direction. This is because the surface area of the pappus decreased throughout the experiment thus giving little area for the air to hit the pappus and cause friction.
Evaluation
My evaluation of the experiment was there were many in accuracy with it. The majority of the experiment was to due human reflexes. There were problems such as:
- You had to be very careful with the pappus otherwise it would break and you would have to start again.
- You couldn’t get the timing for when the pappus left the hand exactly, to when it exactly hit the table.
- The experiment needs to be performed more time for more accurate result.
There were also good points about this procedure such as:
- It was a fair test.
- There were no out side variables affecting it such as wind.
- It was done to the best of my ability.
- Their result seemed to be fairly accurate.
There was much room for improvement in the experiment as I have just mentioned. There can also be some further investigation into such as larger distances to fall; different species of pappus, different conditions such more wind etc.
Criticisms and Improvements
The readings were not so accurate due to the fact that I used seven different seeds during the experiment. This made the experiment an unfair test.
Sheryar Majid 10Q September 2000 Mrs Tyler