Science Buddies: "Ask an Expert"

Hello,
I have the observation and the data for my phototropism experiment. The plants grown with one hole in a milk carton showed 15 degree bending whereas with 4 holes showed 10 degrees bending of the stem. What does this interprets?

Thanks
Piyali

Hello Piyali,

This is a classic experiment. What was your hypothesis at the beginning of the experiment? Do the results conflict with the original hypothesis or are they consistent with the hypothesis? If the result differ from the hypothesis, think about reasons why that might be: what was the layout of the holes (how were they grouped together, in a horizontal line, vertical line, cluster?), were all of the plants grown in the same orientation relative to the light source (window?), how did you measure the angle?

Here is the science buddies page on interpretation and conclusions: https://www.sciencebuddies.org/science- ... l#overview

Cheers,
Colin

The hypothesis was general that with 1 hole, 2 holes and 4 holes it will bend towards light, but while seeing the data I found that angles are different. The holes were horizontal, 6 cms from the bottom and the angle I measured as stem being the straight line and how much it is deflected from there with the help of twist tie and protractor. Is that correct?

Sounds reasonable. There are two things to think about relative to the light and the plant bending, the amount of light and the directionality of the light. With a horizontal line of holes you gave that plant more light but also spread it out. Do you see how that could alter the degree of bending? Can you interpret the results with that in mind?

Cheers,
Colin