biology lab report for international baccalaureate students

Biology Lab Report For

International Baccalaureate

Students

By Sumaya Al Kalla

Table of contents iii

Table of contents Table of contents ............................................................................................................................ iii

Introduction ..................................................................................................................................... v

How to write a scientific Question.................................................................................................. 7

Reflex Action Question: ............................................................................................................. 3

Osmosis of Potatoes Question: ................................................................................................... 3

How to write the aim in a lab report? ............................................................................................. 5

Reflex Action Aim: ..................................................................................................................... 7

Osmosis of Potatoes Aim: ........................................................................................................... 7

How to write Hypotheses in lab report? ......................................................................................... 9

Reflex Action Hypothesis: ........................................................................................................ 11

Osmosis of Potatoes Hypothesis: .............................................................................................. 11

How to write Variables in a lab report? ........................................................................................ 13

Reflex Action Variables:........................................................................................................... 15

Osmosis of Potatoes Variables: ................................................................................................ 15

How to list your apparatus in your lab report? ............................................................................. 17

Reflex Action Apparatus: ......................................................................................................... 19

Osmosis of Potatoes Apparatus: ............................................................................................... 19

How to write the method in your lab report? ................................................................................ 21

Reflex Action Method: ............................................................................................................. 23

Osmosis of Potatoes Method: ................................................................................................... 23

How to write the Results in your lab report? ................................................................................ 25

Reflex Action Results ............................................................................................................... 28

Osmosis of Potatoes Result ....................................................................................................... 29

How to write a conclusion in you lab report? ............................................................................... 31

Reflex Action Conclusion: ........................................................................................................ 33

Osmosis of Potatoes Conclusion:.............................................................................................. 33

How to write an evaluation in a lab report? .................................................................................. 35

Reflex Action Evaluation:......................................................................................................... 37

Osmosis of Potatoes Evaluation: .............................................................................................. 37

Introduction v

Introduction Biology is one of the significant subjects that are taught in school. You can study the

mechanisms, the body systems, and other evolutionary factors that could give reasoning on how

this world is created. Many scientists have discovered the domains of life by simply getting

involved in creating an experiment. As a future scientist, or a biologist you are required to learn

how to complete a biological lab reports. The purpose of this write up is for you to see how well

you preformed in your experiment and whether your results were reliable or not.

The format of writing a lab report is:

(1) Question

(2) Aim

(3) Hypothesis

(4) Variables

(5) Apparatus

(6) Method

(7) Results

(8) Conclusions

(9) Evaluation

One of the major experiments that you will be doing in this biology class is on reflex actions. A

reflex action is measuring the quick response the body takes into action when you get hurt or just

respond to an action. Another important experiment that you should be familiar with is osmosis

of potatoes. Potatoes cells are very close to human cells. This experiment shows how the

concentration of salt will affect potato cells.

How to write a

scientific Question

Question 3

How to write a scientific question? In order to write a scientific question you should always take into consideration of what you

know. For example, we know that fertilizers grow plants. To put this in a scientific question will

be “what type of fertilizers grows plants faster?” In this question you can always take into

consideration testing different kind of fertilizers that could lead to the answering of this scientific

question.

Reflex Action experiment:

Question: how messages from your senses are routed to your brain? And how fast can you react?

As we can see that the question talks about the experiment of reflex action. This question

addresses human behavior towards actions taken place yet experimentally it will be tested using

certain techniques that could help you measure this reflex action.

Osmosis of Potatoes:

Question: how a potato gets Plasmolysize using NaCl?

As a biology student you are required to use scientific terminologies in your lab report. In this

case plasmolysis means the dying of the cell membrane. The question indicates the diffusion of

salt in the cell before it lysis.

How to write the aim

in a lab report?

Aim 7

How to write the aim in a lab report? The aim of the experiment is basically mean what you are trying to find. It is essentially ‘the

answer” of the question. In the aim you try to clarify your unique approach to your experiment.

This approach should be clear to the reader and interesting. State the reason why you are doing

the experiment. You may present this information with research question but must affirm what

you are hoping to investigate in this experiment.


Aim: the aim of this experiment is to determine how fast a person reacts to something.


Aim: the aim of this experiment is to see the change of potato after it has been Plasmolysized

using sodium chloride-table salt (NaCl).

How to write

Hypothesis in lab

report?

Hypothesis 11

How to write a Hypothesis in lab report? In your hypothesis this is where you write what you think is going to happen. Your hypothesis

should include this phrase “if I did this…then this will happen.” This is your plan’s foundation

that indicates whether your experiment was successfully accomplished. The Hypothesis also

gives you a reason for your predictions that is important while writing your conclusion later on in

the report.

As biology students you should know about the atoms and matter. Let us take that as an example

to write the hypothesis. We know that the particles will move faster if we heated them.

Therefore, if we heated water, then the particles in the water will result in a greater collision and

react faster with other components.


Our skin has special sensors to let you detect pressure, heat and even pain. So bundles of nerve

cells, or neurons, carry messages from your skin to your brain. Your brain analyzes the

messages, and you become aware of what’s going on at the surface of your body. This happens

almost instantly.

This experiment is observing the quick actions that occur in human body and you don’t think

about doing them. These are called reflex action. Reflex action lets you jerk away if you react of

something really fast. But not all fast moves are automatic.

Therefore, the fast something is and the slower you assimilate or apprehend it.


if we increased the concentration of NaCl, then the mass of potato and the area of it should be

decreasing because when the cell get plasmolysized then the cell membrane they start getting

closer, closer and pushes out. Also the greater the concentration is then the faster the diffusion.

How to write

Variables in a lab

report?

Variables 15

How to write variables in a lab report?

Variables are the section where you need to know what to control in your experiment and what

the changing quantities are. These variables are controlled variables, independent variables, and

dependent variables. Each experiment’s variable varies from one another.

The controlled variables, also known as constant variable, are the quantities you keep constant in

your experiment. You have to observe this variable carefully because if you alter the quantity

used in this experiment therefore you will not have valid results. In other words it will be a fair

test.

The independent variables are the ones that you change. You should notice as you change the

quantity of these variables then this would allow you to observe what is going to happen.

The dependent variable are the product of a certain reactant or the response to the changes you

made with you independent variable.

Let us look at an example of variables. The question is if we heat a cup of water will the sugar

dissolves more or less? The independent variable (what you change) is the temperature of water

measured in degrees Celsius. The dependent variable (what you observe is the dissolved sugar

and the controlled variable will be the speed of stirring and the type of sugar.


Controlled variables: which sense you use, and when do you drop the ruler.

Dependent variables: how fast person reacts to a ruler.

Independent variables: senses


Independent: concentration of NaCl

Dependent: mass of potato, Area of potato

Controlled: sample cuts from the same potato, Volume of NaCl, Beaker, Same balance used,

Caliper, Stop watch

How to list your

apparatus in your lab

report?

Apparatus 19

How to list your apparatus in your lab

report? The apparatus are the sections where you list the equipments you need to use for your

experiment. These “tools” will help you to conduct the experiment.


1. 1 meter ruler (±0.1cm)

2. paper + pen

3. partner


1. 2 pieces of Potato if not enough them 3

2. 1 Borer size 6

3. 1 Balance

4. 1 Caliper

5. 2 Beakers for each concentration of NaCl

6. 50 ml Sodium Hydroxide (NaCl)

7. stop watch

8. ruler

9. safety goggles

How to write the

method in your lab

report?

Method 23

How to write the method in your lab report? You should be able in this section to write down the steps on how to do the experiment. The

process should be easily written for others to easily follow the process. Moreover, the writing of

the method should be EXACTLY followed by others, as you done it. If diagrams are included,

then you should label your diagrams and number them in the order of what is used first. Make

sure that you include all the safety, cautious, danger, and warning signs for the reader to take his

or her precautions.


1. Firstly you do an experiment each of the three senses: sight, touch, and hearing. You start

with the sight.

2. First you and your partner stand a long each other, one of you hold the ruler and the other

opens her two fingers (index finger and the thumb).

3. Place the ruler between the two fingers.

4. Have your partner release the ruler without telling you. Once it starts to fall, grab it as

fast as you can.

5. Check how many centimeters your fingers are from the starting point.

6. Do the same thing with touch: repeat the process but instead of releasing the ruler at

random timing, touch the person on the hand.

7. As well as with hearing cover your partners eyes and say the word “Go” as soon as you

release the ruler.


1. Wear Safety goggles!

2. Cut pieces of potato using a borer (make sure you use the same size if borer and the same

potato)

3. Weigh the Potato using the mass

4. measure its length using a caliper

5. After adding 50 ml of NaCl in the beaker weigh it so you can see how much of the solute

had been absorb in the potato that will cause diffusion.

6. After you add different concentration of NaCl in the beaker, put the potato in the beaker

and time it between 10 to 15 minutes.

7. After 15 minutes take the potato out of the beaker and weigh it using the balance, make

sure that you record your result.

8. Weigh the beaker and the NaCl after the 15 minutes.

9. Take a caliper to see the length of the potato.

10. Make sure you repeat the experiment and have number of trials.

How to write the

Results in your lab

report?

Result 27

How to write the results in your lab report?

In this section you should record your results that you observed in your experiment. After

recording you should process your data. Represent your result in an easy way for others to read,

understand and compare results.

You could record your data in a table for example. While processing your data, you should take

into consideration to process and analyze your data. This is where most students forget to

analyze their data and end up getting penalized.

If you included graphs in your analyzation or calculations carefully you should add the

uncertainties of your result. The uncertainty value is a numerical value presented as plus or

minus. For example a result reported as 1.23 ± 0.05 means that you have some degree of

confidence that the true value falls in between 1.18 and 1.28.

28 Biology Lab Report


The mass of beaker: 34.88

The mass of beaker + NaCl: 84.03

The mass of NaCl: 49.142

Area of the potato: (two x pie x radius x height) + (two x pie x radius squared)

Mass of

NaCl

before

Mass of

potato

before

Area of potato before Mass

of

NaCl

after

Mass of

Potato After

Area of Potato after

0.5 M

of

NaCl

49.142 2.14 Radius: 1.02

Height: 2.2

2(pie)(1.02)(2.2)+(2)(1.02 x 1.02)= 17.16

48.26 2.14 R: 1.02

H: 2.1

2(pie)(1.02)(2.1)+2(1.02x1.02)= 15.54

0.5 M

of

NaCl

49.142 2.13 R: 1.02 H: 2.0

2(pie)(1.02)(2.0)+(2)(1.02 x 1.02)=

14.90

48.43 2.12 R: 1.02 H: 2.1

2(pie)(1.02)(2.1)+2(1.02x1.02)= 15.54

0.8 M

of

NaCl

49.142 2.14 Radius: 1.02

Height: 2.1 2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)=

15.54

47.21 2.03 R: 1.02

H: 2.0 2(pie)(1.02)(2.0)+2(1.02x1.02)= 14.90

0.8 M

of

NaCl

49.142 2.15 Radius: 1.02 Height: 2.1

2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)=

15.54

47.23 1.95 R: 1.02 H: 2.1

2(pie)(1.02)(2.1)+2(1.02x1.02)= 15.54

1.0 M

of

NaCl

49.142 2.14 Radius: 1.02

Height: 2.1 2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)=

15.54

47.13 1.87 R: 1.02

H: 1.9 2(pie)(1.02)(1.9)+2(1.02x1.02)= 14.26

1.0 M

of

NaCl

49.142 2.14 Radius: 1.02 Height: 2.1

2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)=

15.54

47.13 1.87 R: 1.02 H: 1.9

2(pie)(1.02)(1.9)+2(1.02x1.02)= 14.26

1.5 M

of

NaCl

49.142 2.14 Radius: 1.02

Height: 2.1 2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)=

15.54

47 1.74 R: 1.02

H: 1.8 2(pie)(1.02)(1.8)+2(1.02x1.02)= 13.62

1.5 M

of

NaCl

49.142 2.13 Radius: 1.02 Height: 2.1

2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)= 15.54

46.72 1.70 R: 1.02 H: 1.7

2(pie)(1.02)(1.7)+2(1.02x1.02)= 12.98

2.0 M

of

NaCl

49.142 2.14 Radius: 1.02

Height: 2.1 2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)=

15.54

46.51 1.53 R: 1.02

H: 1.6 2(pie)(1.02)(1.6)+2(1.02x1.02)= 12.33

2.0 M

of

NaCl

49.142 2.13 Radius: 1.02

Height: 2.1

2(pie)(1.02)(2.1)+(2)(1.02 x 1.02)= 15.54

46.49 1.50 R: 1.5

H: 2.1

2(pie)(1.02)(1.5)+2(1.02x1.02)= 11.69

Results 29


Person A

Sight (in cm) Sound (in cm) Touch (in cm)

22.0 11.6 29.0

44.0 20.0 13.5

44.3 5.7 13.9

45.4 28.0 10.6

6.0 28.9 7.8

Average: 32.2 Average:18.8 Average:15.0

Mode: 44 Mode: 28 Mode: 13

Median: 44 Median:20 Median: 13.5

Person B

Sight (in cm) Sound (in cm) Touch (in cm)

6.5 10.0 17.5

21.0 6.5 7.0

16.3 32.0 9.0

13.4 20.5 28.5

2.2 6.5 26.0

Average: 11.9 Average: 15.1 Average: 67.2

Mode: - Mode: 6.5 Mode: -

Median: 13.4 Median: 10.0 Median: 17.5

Analyzed data

Sight (in cm) Sound (in cm) Touch (in cm

Total Average

length of the # of

people

14.56 19.74 26.41

Total mode of all 11.27 19 15.6

Total median of

all

12.7 18.1 26.7

How to write a

conclusion in you lab

report?

Conclusion 33

How to write a conclusion in you lab report? Mostly in your conclusion it is a paragraph summing up what you did throughout the experiment.

Your conclusion should include whether your hypothesis is correct. You should state whether

your experiment worked or not. You should explain the results you have collected and base your

explanation on your analysis. You can identify the experimental errors that occurred during your

experiment and to explain how it influenced your results. You can also prioritize errors and

discuss where they came from. Include some elaboration based on what you learned in biology

class.


My hypothesis was correct, Reflex actions are quite common and easy to notice. As we can see

this experiment shows how the human respond towards fast movement. This is by created a

nerve impulse that travels along a sensory nerve to the spinal cord.

I got the results that I observed because I followed my method, and tried to avoid experimental

error for example, when you place the ruler between the fingers do you place it up or down the

fingers.

Looking at the bar graph, I processed my data using mean, median and the mode. With each of

the following the graph illustrate the sense of sight had the lowest average, mode and median

because when my partner dropped the ruler I saw her dropping it so this will be faster for my

brain to reach the signal. The sense of sound was the second lowest of all, because when you

hear the word “Go” as soon as my partner drops the ruler it will take time for me to catch the

ruler. This could also count as an experimental error, because there may be some echo in the area

that I was in, or she said “Go” before actually dropping it. The last sense was the touch, the touch

every person found difficulties in it.


My hypothesis approved the point were when the mass of potato decreases the more

concentration we have. The data above and the graph on the following page show different

readings that support my point. Finding the mass of NaCl before and after helped me to

determine how much potato needed NaCl to be plasmolysize, but I noticed as we increase in the

concentration the less the NaCl gets but the potato is releasing water and when water react with

salt it will be diluted.


I also collected in the data the mass of potato before and after it was reacted with NaCl, because I

wanted to see whether the mass increases or decreases, but it was decreasing because the potato

was losing molecules of water. Also as it shown in the graph, the rise of NaCl in its morality,

therefore the mass of potato after diffusion decreases.

How to write an

evaluation in a lab

report?

Evaluation 37

How to write an evaluation in a lab report? In your evaluation you will need to evaluate your experiment by answering the following

questions

What are the strengths and the weaknesses of your experiment?

How can you improve your experiment to avoid the weaknesses?

Could you state where did the errors come from?

How would you do this experiment differently if you were to do it again?


To improve this experiment you need to make sure of taking measurements is it below or above

your thumb (as you hold the ruler). Make sure of the place that you are in; it doesn’t echo and be

far away from others, try to avoid noisy areas. Make sure when you tap your hand on your

partner’s hand to tap it gently but at the same time make them feel the tap not very hard and not

very soft.

And this is how messages/ signals are routed. Much of the work of the nervous system depends

upon established pathways between neurons.


In this experiment we tested how potato cell gets plasmolysize using different concentration of

NaCl (sodium Hydroxide) in order to see what changes it could make.

The shape of the potato didn’t change, according to my collection of data, but the mass and the

area of the potato decreased because the cells will push out of the cell.

My experiment was reliable; I did more than one trial to make sure that I approximately get the

same method for each of the following data collection. My results were almost valid because I

was able to control the mass of the potato and the area of it, but it only differs by 0.5 or less.

Things that went wrong in my experiment were, the potato’s I didn’t use the same potato and this

could affect my results, by the amount of enzymes and water there is inside a one kind of potato

that is used. But what I did was use the potato to collect information for my data processing and

the second potato for the second half. Another thing that could go wrong that could affect my

results was the adding of 50 ml of NaCl, because I could add less or more that 50 ml and some


could be evaporated. Also, the water inside the potato could be evaporated therefore the potato

could get dry.

I can improve this experiment by taking the temperature of the room and work on the same

temperature so no evaporation happen in potatoes or in NaCl (sodium Chloride). Had minimum

three trials to make this experiment reliable and control each variable to have valid results.

Index 39

Index A

Aim ............................................................. 5

Osmosis of Potatoes ................................ 7

Reflex Action experimen ........................ 7

Apparatus .................................................. 17

Apparatus

Osmosis of Potatoe ............................... 19

Reflex Action experiment: .................... 19

C

Conclusion ................................................ 31

Conclusion

Osmosis of Potatoes .............................. 33

Reflex Action experiment ..................... 33

E

Evaluation ................................................. 35

Evaluation



H

Hypothesis................................................... 9



I

Introduction ................................................. v

M

Method ...................................................... 21

Method



Q

Questions

Osmosis of Potatoes ................................ 3

Reflex Action experiment ....................... 3

R

Results ....................................................... 25



S

Scientific Question ...................................... 7

V

Variables ................................................... 13


Reflex Action experimen ...................... 15

biology lab report for international baccalaureate students

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