My 7 year old daughter has a science project due on March 1, 2008 for her first grade class. The experiment is "what happens to a plant when you put it in a jar?" We are required to use the scientific method and will present to the class in early March.
Our hypothesis is that the plant will die. We have two plants, one in the jar and one outside of the jar. Both are on the kitchen counter (I've included a link to the photo of the plants at the bottom of this post). We watered both plants prior to putting the one in the jar. Our thought is that the plant in the jar needs to be left alone for the duration (since it is in the jar, technically, we should not be opening the lid to water and such). We believe that eventually, the lack of nutrients (i.e. water, CO2) will kill the plant in the jar, while the plant outside the jar will thrive because it will be watered and will get CO2.
I am not concerned if our hypothesis is right, because that is the fun of the experiment (learning). However, I do have some questions:
1 - Are we on the right track?
2 - What other types of research should we/could we be doing?
3 - Am I correct to think that we should not be opening the lid on the jar to feed the plant?
Any insight/thoughts would be greatly appreciated.
Thanks.
Joe
Link to photo of plants
http://picasaweb.google.com/ozweego94/U ... 4VxiPshZa4
What happens to a plant when you put it in a jar?
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donnahardy2
- Former Expert
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Re: What happens to a plant when you put it in a jar?
Hi Joe,
You are absolutely on the right track when you mention fun and learning in doing the project. At this age, I would encourage your daughter to think about and enjoy her project, and do as much as she is able to do.
Plants need carbon dioxide to make sugars, and they produce carbon dioxide during respiration, so I don't know if your plant will run out of CO2. Plants will die if they get too dry, but if the lid is airtight, then the water vapor should not be able to escape from the jar. If the lid is not airtight, and the plant does start to dry out, then you could have your daughter water the plant inside the jar. In science experiments, you want to maintain all conditions identical, except for one variable, and so keeping the soil at the same moisture level would be acceptable. Then any differences in the experiment would be due to the environment inside the jar. But, it's your daughter's experiment, so you should let her decide.
Your experimental design is good. You have the two plants and you have one variable (plant inside and out of a jar). You might encourage your daughter to think about what differences in the environment a jar would cause. If sun shines directly on the jar, there will be a difference in temperature. There will also be a difference in humidity inside the jar, so you might want to explain about evaporation. Can your daughter think of any other differences?
You should help your daughter plan how she is going to present her results now. Is she going to take pictures every few days? This would be good, as measuring plant height, temperature, or humidity is too complicated for a project at this age.
You should definitely get some books on plants from the library and read them to your daughter, if she can't read them. You can help her become an expert on plants so she can explain her project to others.
Good luck!
Donna Hardy
You are absolutely on the right track when you mention fun and learning in doing the project. At this age, I would encourage your daughter to think about and enjoy her project, and do as much as she is able to do.
Plants need carbon dioxide to make sugars, and they produce carbon dioxide during respiration, so I don't know if your plant will run out of CO2. Plants will die if they get too dry, but if the lid is airtight, then the water vapor should not be able to escape from the jar. If the lid is not airtight, and the plant does start to dry out, then you could have your daughter water the plant inside the jar. In science experiments, you want to maintain all conditions identical, except for one variable, and so keeping the soil at the same moisture level would be acceptable. Then any differences in the experiment would be due to the environment inside the jar. But, it's your daughter's experiment, so you should let her decide.
Your experimental design is good. You have the two plants and you have one variable (plant inside and out of a jar). You might encourage your daughter to think about what differences in the environment a jar would cause. If sun shines directly on the jar, there will be a difference in temperature. There will also be a difference in humidity inside the jar, so you might want to explain about evaporation. Can your daughter think of any other differences?
You should help your daughter plan how she is going to present her results now. Is she going to take pictures every few days? This would be good, as measuring plant height, temperature, or humidity is too complicated for a project at this age.
You should definitely get some books on plants from the library and read them to your daughter, if she can't read them. You can help her become an expert on plants so she can explain her project to others.
Good luck!
Donna Hardy
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ozweego94
- Posts: 2
- Joined: Sun Jan 20, 2008 6:49 am
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- Project Question: What happens to a plant when you put it in a jar?
- Project Due Date: March 1, 2008
- Project Status: I am conducting my research
Re: What happens to a plant when you put it in a jar?
Ok...so the project is over and we are reviewing our results. Trying to keep all conditions the same with the exception of one plant in a jar and one out of a jar, the plant in the jar ended up dying - which matched our hypothesis. My only question is - should that have happened? Although the jar was not air tight, it was a small jar. We did water the plant in the jar a much as the one out of the jar - about 2 or 3 times per week. There definitely appeared to be a greenhouse effect going on in the jar, as we did see condensation form on the inside of the jar top and the temperture certainly felt a bit warmer.
Eventually, though, we had to stop watering the plant in the jar as the soil began to look super-moist - almost like it could not hold any more water. Why did this happen? Is it that the covered jar did not allow for enough evaportation? That is my thought. It's like it drowned itself. Or, was the confinement of the jar just too much and ultimately there was not enough air?
I would appreciate some final thoughts. Attached is what the plants looked like at the conclusion of the experiment.
Plant A
http://lh6.google.com/ozweego94/R8mi8eg ... imgmax=576
Plant B
http://lh5.google.com/ozweego94/R8mi9Og ... imgmax=576
Eventually, though, we had to stop watering the plant in the jar as the soil began to look super-moist - almost like it could not hold any more water. Why did this happen? Is it that the covered jar did not allow for enough evaportation? That is my thought. It's like it drowned itself. Or, was the confinement of the jar just too much and ultimately there was not enough air?
I would appreciate some final thoughts. Attached is what the plants looked like at the conclusion of the experiment.
Plant A
http://lh6.google.com/ozweego94/R8mi8eg ... imgmax=576
Plant B
http://lh5.google.com/ozweego94/R8mi9Og ... imgmax=576
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staryl13
- Former Expert
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- Occupation: Research Assistant
- Project Question: Neuroregeneration
- Project Due Date: N/A
- Project Status: Not applicable
Re: What happens to a plant when you put it in a jar?
Hi!
Could you please tell some of the other variables which you kept constant? i.e. did both plants receive about the same amount of sunlight, etc..
Also, the following links are about a project of plants growing in a jar, and they go through detailed explanations as to why the plants can thrive in such an environment. I think that watering the plant might have caused it to die because in a closed system (jar) water would continuously be replenished within the jar so adding more water is not necessary.
http://www.crsep.org/PerplexingPairs/Li ... 022603.pdf
http://www.crsep.org/PerplexingPairs/Li ... 030603.pdf
http://www.crsep.org/PerplexingPairs/Li ... 031203.pdf
http://www.crsep.org/PerplexingPairs/Li ... 031903.pdf
Hope this helped!
Could you please tell some of the other variables which you kept constant? i.e. did both plants receive about the same amount of sunlight, etc..
Also, the following links are about a project of plants growing in a jar, and they go through detailed explanations as to why the plants can thrive in such an environment. I think that watering the plant might have caused it to die because in a closed system (jar) water would continuously be replenished within the jar so adding more water is not necessary.
http://www.crsep.org/PerplexingPairs/Li ... 022603.pdf
http://www.crsep.org/PerplexingPairs/Li ... 030603.pdf
http://www.crsep.org/PerplexingPairs/Li ... 031203.pdf
http://www.crsep.org/PerplexingPairs/Li ... 031903.pdf
Hope this helped!
"There is a single light of science, and to brighten it anywhere is to brighten it everywhere." -Isaac Asimov
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donnahardy2
- Former Expert
- Posts: 2671
- Joined: Mon Nov 14, 2005 12:45 pm
Re: What happens to a plant when you put it in a jar?
Hi Joe,
Congratulations on following through to complete the experiment! By now, your daughter should understand what conditions plants require in order to survive and grow, e.g. soil, water, light, air, and an appropriate temperature. The plant in the jar died because one of these environmental conditions was not right. Since the jar was not airtight, it is unlikely that a difference in carbon dioxide or oxygen cause the problem. You have given two clues about the cause of death that compare with the conditions of the plant that was not in the jar. First, is the warmer temperature. Perhaps the sunlight shining through the jar made the temperature so high that the plant could not survive. Second, is the higher moisture level inside the jar. Most plants require air in the soil and will die if there is no air (oxygen). That's why trees in flooded locations will die after a period of time. Another problem with conditions that are too wet is that microorganisms can grow in the soil that will kill plant roots (e.g. damping off fungus). Your daughter has observed the difference in the growth of the two plants, knows what plants need to grow, so perhaps she could think of difference that would have caused the plant in the jar to die. This experiment is a very good experiment, but did not give you results that will determine why the plant died. Perhaps you could ask your daughter to think of a new experiment that would give more information. For example, perhaps an experiment could be done that would include two plants under identical conditions, except for temperature (one at ambient, one at the temperature inside the jar). Or another experiment where conditions would be identical except for the moisture level of the soil. You would not do the experiment, of course, because you've already done plenty for this year’s project, but it would be good if you daughter could think of the next experiment, and next time plan to measure the temperature with a thermometer, or the moisture level of the soil with a moisture-meter in another controlled experiment.
Good luck!
Donna Hardy
Congratulations on following through to complete the experiment! By now, your daughter should understand what conditions plants require in order to survive and grow, e.g. soil, water, light, air, and an appropriate temperature. The plant in the jar died because one of these environmental conditions was not right. Since the jar was not airtight, it is unlikely that a difference in carbon dioxide or oxygen cause the problem. You have given two clues about the cause of death that compare with the conditions of the plant that was not in the jar. First, is the warmer temperature. Perhaps the sunlight shining through the jar made the temperature so high that the plant could not survive. Second, is the higher moisture level inside the jar. Most plants require air in the soil and will die if there is no air (oxygen). That's why trees in flooded locations will die after a period of time. Another problem with conditions that are too wet is that microorganisms can grow in the soil that will kill plant roots (e.g. damping off fungus). Your daughter has observed the difference in the growth of the two plants, knows what plants need to grow, so perhaps she could think of difference that would have caused the plant in the jar to die. This experiment is a very good experiment, but did not give you results that will determine why the plant died. Perhaps you could ask your daughter to think of a new experiment that would give more information. For example, perhaps an experiment could be done that would include two plants under identical conditions, except for temperature (one at ambient, one at the temperature inside the jar). Or another experiment where conditions would be identical except for the moisture level of the soil. You would not do the experiment, of course, because you've already done plenty for this year’s project, but it would be good if you daughter could think of the next experiment, and next time plan to measure the temperature with a thermometer, or the moisture level of the soil with a moisture-meter in another controlled experiment.
Good luck!
Donna Hardy