Scientific Investigation stage 4-Lab Report

Name: Bhagya Sree Nagarajan
Class: 107
Index No.: 2
Date: 22 July 2012

Aim of experiment: To find out how bright light and the lack of light affects he growth of mealworms.


Hypothesis: The speed of growth of the mealworms kept in bright light will be lower than those kept in the dark.

Independent variable: the absence of light


Important controlled variables:

1. same type/species of mealworms in both set-ups.
2. same number of mealworms in each set-up
3. same location throughout the experiment.
4. same amount of space for each side.
5. the container is ventilated equally.

Dependent variable: growth speed of mealworms 

Assumptions: All the mealworms have vision. All of them are at an equally developed stage.

Materials and apparatus: 

1. 4 mealworms
2. a container with holes
3. black cardboard
4. laser pointer/ handheld torch
5. food for mealworms in the container
6. black paper
7. scotch tape

Procedure:

1. Place a cardboard barrier (that is black to ensure no light from the other side passes through) between the 4 mealworms such that 2 are on each side and the container is divided equally.
2. Cover up the left side of the container with black paper on the outside ensuring that maximum light is blocked. Label this side A.
3. Place a handheld torch towards the right side of the container. Label this side A.
4. Watch the growth of the mealworms over a period of 5 days or until they turn into a beetle, whichever shorter.
5. Record observations.

 Biological Drawing of experiment set-up:

Data Collection/Observations made

End of Day 1: There is no change observed.

End of Day 2: There is a shed skin on side A. One of the mealworms of side A has moulted, showing that it has increased in size. No change is observed on side B.

End of day 3: There is another shed skin on side A, showing thta another mealworm has moulted. Both mealworms on side B are very close to the cardboard barrier. Neither of them have moulted.

End of day 4: The mealworms on side A seem to have grown longer. Both of them have moulted/ shed skin again. The mealworms on side B still stay close to the barrier and one of them has started trying to climb over the barrier.

End of Day 5: The mealworms on side A are dormant and stay still. They are curled up. One of the mealworms on side B has climbed up slightly more than half the length of the barrier. The other mealworm moves very seldom and only twitches if the container is disturbed/shaken.

Data Analysis:

Side A: By observing the mealworms on side A, we can see changes such as their growth in size shown by the shedding of skin and their dormant stage at the end of the experiment. I can deduce that they have developed from their larval stage to the pupal stage.

Side B: The observations of the mealworms on side B show us that the intense light have caused them difficulty in growth as they have visibly grown slower. Only one mealworm managed to moult and the other has been do "desperate" that it tried to climb over the cardboard barrier. Neither of them have moved on to the pupal stage.

Conclusion:

Therefore, the data supports my hypothesis. The presence of bright light causes mealworms to grow slower and/or hinders their growth process.