biology cw help .. need to give in by tmrw !!

ok i m doing bio cw on the rate of photosynthesis .. my teacher gave me a 4/8 on my cw cus my method didnt make sense .. can someone help me and make sense of the method i mean help me write it or smth sing scientific wording etc ... the method i wrote is pasted below

Method ( only some of it didnt make sense so i m juts pasting the part which didnt make sense ) its not the whole method .. only some of the beginning is missing ..

•The cut end has to be inserted into the bulb of the burette carefully
•Then the burette is lowered and it has to be made sure that the bulb is imersed in the water
•A bench lamp has to be at a fixed distance, which is 15 cm, from the beaker and it has to be made sure that that the light is directly facing the bulb in the water
•Another beaker filled with water has to be placed in between the main beaker with the bulb and light bulb. The beaker is used to absorb any heat generated from the light bulb
•After setting all the apparatus up, the syringe on top of the burette has to be pulled in order for the water to get into the burette
•The rubber tubing has to be closed with a screw as tightly as possible
•Then a solution of sodium hydrogen-carbonate has to be made. It has to be noted that this is an experiment measuring rate of photosynthesis with carbon dioxide concentration. It would be best if minimum amount of sodium hydrogen-carbonate is put and then the concentration is increased every time a new reading is measured
•Then the light is turned on. The elodea has to be allowed to settle in the conditions so a 2 min wait will be appropriate. When the bubbles start appearing, the stopwatch is started over a 1-minute period. It is measured over a 1-minute period because the bubbles do not collect so rapidly. It takes time depending upon the conditions. The plant has to get used to the conditions first
•After a minute, the light is switched off and the screw is opened a bit. This is to let the bubbles go into the gas column for measurement
•When the bubbles go in, the screw is closed again tightly and the length of the bubble is measured by reading the measurement on the gas column. It has to be remembered that the length has to converted into volume
•This can be done twice with the same concentration so the results are reliable
•To take a new measurement, the concentration has to be changed and the plunger of the syringe has to be pulled out to withdraw all the air bubbles
•The steps are repeated again to measure the rate of photosynthesis
•A total of 6 or 7 readings are taken

Reply 1

Golden Maverick

4

ammarb87

ok i m doing bio cw on the rate of photosynthesis .. my teacher gave me a 4/8 on my cw cus my method didnt make sense .. can someone help me and make sense of the method i mean help me write it or smth sing scientific wording etc ... the method i wrote is pasted below

Method ( only some of it didnt make sense so i m juts pasting the part which didnt make sense ) its not the whole method .. only some of the beginning is missing ..

•The cut end has to be inserted into the bulb of the burette carefully
•Then the burette is lowered and it has to be made sure that the bulb is imersed in the water
•A bench lamp has to be at a fixed distance, which is 15 cm, from the beaker and it has to be made sure that that the light is directly facing the bulb in the water
•Another beaker filled with water has to be placed in between the main beaker with the bulb and light bulb. The beaker is used to absorb any heat generated from the light bulb
•After setting all the apparatus up, the syringe on top of the burette has to be pulled in order for the water to get into the burette
•The rubber tubing has to be closed with a screw as tightly as possible
•Then a solution of sodium hydrogen-carbonate has to be made. It has to be noted that this is an experiment measuring rate of photosynthesis with carbon dioxide concentration. It would be best if minimum amount of sodium hydrogen-carbonate is put and then the concentration is increased every time a new reading is measured
•Then the light is turned on. The elodea has to be allowed to settle in the conditions so a 2 min wait will be appropriate. When the bubbles start appearing, the stopwatch is started over a 1-minute period. It is measured over a 1-minute period because the bubbles do not collect so rapidly. It takes time depending upon the conditions. The plant has to get used to the conditions first
•After a minute, the light is switched off and the screw is opened a bit. This is to let the bubbles go into the gas column for measurement
•When the bubbles go in, the screw is closed again tightly and the length of the bubble is measured by reading the measurement on the gas column. It has to be remembered that the length has to converted into volume
•This can be done twice with the same concentration so the results are reliable
•To take a new measurement, the concentration has to be changed and the plunger of the syringe has to be pulled out to withdraw all the air bubbles
•The steps are repeated again to measure the rate of photosynthesis
•A total of 6 or 7 readings are taken

The bit in bold does not make sense, it's not well worded.
Re-write it more like:

•

Leave the elodea for around 2 minutes to accomodate to the experimental conditions, until bubbles start to be formed

•

Then switch on the light and stopclock simultaneously

Explain why you let it run for one minute before or after the method, otherwise it might get confused.

EDIT: Don't know about you but I always found it better to do a numbered list, with information on why you are doing such and such as sub bullets from that list. eg:

1.  Add this
2.  Add that
  -   This helps...
  -   To stop...
3. Blah
4. Repeat steps 1-3 four times
etc

Reply 2

frizzy_locks

2

ammarb87

ok i m doing bio cw on the rate of photosynthesis .. my teacher gave me a 4/8 on my cw cus my method didnt make sense .. can someone help me and make sense of the method i mean help me write it or smth sing scientific wording etc ... the method i wrote is pasted below

Method ( only some of it didnt make sense so i m juts pasting the part which didnt make sense ) its not the whole method .. only some of the beginning is missing ..

•The cut end has to be inserted into the bulb of the burette carefully
•Then the burette is lowered and it has to be made sure that the bulb is imersed in the water
•A bench lamp has to be at a fixed distance, which is 15 cm, from the beaker and it has to be made sure that that the light is directly facing the bulb in the water
•Another beaker filled with water has to be placed in between the main beaker with the bulb and light bulb. The beaker is used to absorb any heat generated from the light bulb
•After setting all the apparatus up, the syringe on top of the burette has to be pulled in order for the water to get into the burette
•The rubber tubing has to be closed with a screw as tightly as possible
•Then a solution of sodium hydrogen-carbonate has to be made. It has to be noted that this is an experiment measuring rate of photosynthesis with carbon dioxide concentration. It would be best if minimum amount of sodium hydrogen-carbonate is put and then the concentration is increased every time a new reading is measured
•Then the light is turned on. The elodea has to be allowed to settle in the conditions so a 2 min wait will be appropriate. When the bubbles start appearing, the stopwatch is started over a 1-minute period. It is measured over a 1-minute period because the bubbles do not collect so rapidly. It takes time depending upon the conditions. The plant has to get used to the conditions first
•After a minute, the light is switched off and the screw is opened a bit. This is to let the bubbles go into the gas column for measurement
•When the bubbles go in, the screw is closed again tightly and the length of the bubble is measured by reading the measurement on the gas column. It has to be remembered that the length has to converted into volume
•This can be done twice with the same concentration so the results are reliable
•To take a new measurement, the concentration has to be changed and the plunger of the syringe has to be pulled out to withdraw all the air bubbles
•The steps are repeated again to measure the rate of photosynthesis
•A total of 6 or 7 readings are taken

first of all i think i would advise you just to put way more detail in such as how much sodium hydrogen-carbonate are you going to make? don't just say you're going to make a solution, and don't assume in a method that the person reading it i.e your teacher knows all that she does (thats a tip i've laways been told)
how are you timing it, stop watch, clock etc?
i think by using more detailed steps and repeating what you are doing, what you are scewing back on and where for example, should increase your mark as i did A LOT of this and got full marks for my method.

hopefully some more people can give you some other advise too by tomorrow.

Reply 3

ammarb87

OP

thanx for the advice guys .. just need a bit more advice .. the thing is that the solution of sodium hydrogen carbonate was already made so how do i write in the method on how to make the solution ?
Any more advice ?

Reply 4

frizzy_locks

2

i think in this case you would just say that it was previously made.

so - i used a solution of sodium hydrogen carbonate which was previously made ......

or something to that effect.

Reply 5

SB

2

ammarb87

thanx for the advice guys .. just need a bit more advice .. the thing is that the solution of sodium hydrogen carbonate was already made so how do i write in the method on how to make the solution ?
Any more advice ?

Find out what concentration it was at and just quote that - they need to know. And say it was ready made-sorted!

Also, it might be easier to write (and read) if you wrote it like a series of orders to the most stupid person EVER who's never done any biology before in their life e.g.
•Carefully insert the cut end into the burette bulb
•Lower the burette, ensuring the bulb is immersed in water
•Fix a bench lamp 15cm from the beaker with its bulb directly facing the water.
•Fill another beaker with water and place it between the main beaker and the light bulb. This will absorb any heat generated from the light bulb

Cut end of what? How big is the beaker? How much water is in it? How bright is the bulb?
Just be much more specific - use any measurements available to you. Good luck! :ciao: