View Full Version : Testing different soils for maximum water retention-hypothesis and experiment needed

11-28-2005, 03:06 PM
For my honors science project, i have chosen to do "What type of soil is best for maximum water retention" My hypothesis was :The more dense a soil is, the more water it will hold. However, my teacher told me i wouldn't be able to use "dense" because i couldn't measure the density of soil. :mad: So now, i need a new hypothesis i was thinking about using the word "porosity", but now i don't know how to word it. Also, for my experiment, i was thinking of taking things like mulch, sand, clay, silt, potting soil (like the kind that comes in bags), and a rocky soil (i can get that in my yard ;) ) I think i want to dry the "soil" out, then add a set amount of water (like 1 cup or something) Then somehow collect the excess amount of water, subtract that from 1 cup, and i can figure out how muchh the soil is holding. Is this a good, reliable, scientifically correct experiment? Thanks in advance!!! :) :)

01-25-2006, 08:25 AM
can u try n see whether this hypothesis is good enough..
"If the soil's particles are closer, then the soil will retain more water"
email me at cheah_cheryl@yahoo.com


01-25-2006, 04:51 PM
Thanks, but i am already finished with my project. My hypothesis turned out being "The heavier a soil is when dry, the more water it will hold."


01-25-2006, 07:14 PM
okay..thanks a lot...um, can i use urs if my hypothesis didnt turn out good??btw, i am doing the project now....so i am figuring out the hypothesis n some of the other things...(conclusion, some info.......etc)if u can, can you pls help me with the stuff??thanx a lot!!

01-26-2006, 01:00 PM
What is your NEW project going to be on???

01-26-2006, 02:54 PM
Sure!!! Are you doing the same project as me? It isn't the most exciting thing in the world, but it works well! So, do you have a research question? Like mine was "What type of soil is best for maximim water retention" cause like, idk, yours could be different. I used 5 "soils" sand,peat moss, potting soil, mulch and soil i dug up from my yard (aka yard soil :rolleyes: ) So, exactly how are you doing your project?

01-27-2006, 03:43 PM
thanx to both of you(grinner & equestrian) for helping me out...my project is mainly about what kind of soil is the best in retaining water.if you can give me some information about where can i get the details on the internet(which website or wateva...)i am jus using fine sand, small stones, and coarse sand....i planned to like put them into bottles(cutted into half{left only the mouth of the bottle}) n then pour water into it to see which soil holds the water longer...n jus roughly draw it into a table....is it okay if my project goes on like dat?do you understand what am i talking about?:)

thanks for helping me!!it really helps a lot!!

01-27-2006, 04:22 PM
The reason why you can't measure the density of soil is because if you pack the soil, it'll have a larger density. Density is measured using volume and mass. If you're just saying which mass is larger in one container, that is as inaccurate as saying density.

I suggest you actually measure the MASS (also known as weight) of the soils and have all the mass equal to each other. Then look at the volume of all the soils. You can see know which ones are more COMPACT and which ones are more LOOSE.

Make your hypothesis in terms of compact and loose.

Good luck!:D

01-28-2006, 02:31 PM
i used "If the soil particles are closer to each other, then the soil can retain more water"...i guess it'll work....but anyway, thanks for helping out!!i really appreciate that....

if you can give me more information about that, thanx!

01-29-2006, 07:13 AM
Ok, i'm getting what you're doing. According to your hypothesis, the fine sand should hold the most water, followed by the coarse sand and then the rocks. That's great, however i might sugggest using somethihng like potting soil to compare to the sand, since it's easy to find and works well for this type of project.

01-29-2006, 08:38 AM
I would suggest you do your experiment with flower pots with holes underneath. All you have to do is pour the water slowly into the pot that has some soil and let the excess water drain from the holes and into another container. Then all you'll have to do is measure how much water is in the container. Also, remember to pour slowly, cause it takes time for the soil to absorb the water.

Bonne chance!

01-29-2006, 11:28 AM
Oh yes, Cheryl. If you want some pictures, email me at equestrian_239@yahoo.com and i can give you some pics of my experiment.:)

01-30-2006, 07:27 PM
it could help a lot!!!okay, i will email u....if you hv some more information about this topic jus let me know...i'll be gratefull if u can help me with all these problems...


01-30-2006, 08:03 PM
I would suggest you look at the different potting soils. What is the difference between good and bad potting soil? You know, a good "so what" for your experiment is potting soil and agriculture soil. What I mean by a so what is "why is your experiment important?" "what does your experiment contribute," or basically, "so what if sand is worse/better at holding water than regular soil?" You could then tell them about the agriculture and need to have good soil, as well as the potting soil industry. If you can, research into the so what. Look at the ways the agricultural industry maintain good soil. What kind of soil is good for agriculture?

Good luck!

01-31-2006, 12:11 PM
Yes, i sent you the pics. I'd suggest to use pots with holes in the bottoms, and then use plastic containers to catch the water that comes out, since that worked well for me and that's how my science teacher told me to do it. Pour the water slowly, like dreamerofeternity mentioned. Get a set amount of soil and water (i did 4 cups of soil and 2 cups of water for each) So they're all the same, let them be for an hour or longer, take the water expelled and subtract from the original amount of water to find out how much water is held.....but you probably already know that lol.

02-01-2006, 12:31 PM
oh my gosh!that idea is so great!!!thanx a lot equestrian n dreamerofeternity...this one really did help a lot....i'll try that out...thanx for that!!!i really appreciate that...

03-04-2006, 02:32 AM
wow! thats a good idea. i am in yr 8 doing a home project investigation and i have been searching for an idea for ages, the only problem is, how exactly do you test it? please answer my question because i need to choose my idea immediately!!!!!!!!!

03-04-2006, 11:57 AM
Basically, this is what i did. I got sand, mulch, peat moss, potting soil, just dug up some soil from my yard.. Dry out soil on cookie sheets in oven until there is no more moisture left in the soil. I got these plastic pot thingies with holes in the bottom, and cut some pieces of screen to fit in the bottom of the pots. I put 4 cups of soil in each pot, weighed them, and then used popsicle sticks to keep them over little ziplock/glade/rubbermaid plastic containers. I poured 2 cups of water into each one, slowly. I let the water drip through for about 1 1/2 hours. After that, i took the water that had dripped out and measured it, then subtracted it from the original 2 cups and came up with how much water was held in the soil. I weighed the soil again(as with my project, i compared weight change to water retention). I conducted the experiment a second time, but the resulults were basically the same.

03-04-2006, 05:13 PM
wow! thats a good idea. i am in yr 8 doing a home project investigation and i have been searching for an idea for ages, the only problem is, how exactly do you test it? please answer my question because i need to choose my idea immediately!!!!!!!!!okay, i just like measure the soil's weigh to make it constant like maybe 1 pound....and then i jus pour a amount of water into the soil and measure the time for the water to drain out.....i just finish my project, so i know it.....you need to hv at least 3 types of soil....you can get it frm your yard....

05-05-2006, 02:57 AM
Equestrian...and anyone else who can help... How long did you bake the soil to dry it out and at what temperature? Is that the best way to do it? :confused: :confused:

05-05-2006, 03:00 PM
I baked the soil at 200 degrees (the lowest my oven would go) and let it fry for like, 10 minutes, and checked on it. You have to flip it, so get the stuff on the bottom dry, and put it in until all the moisture is out. It took some of mine nearly an hour! Use an old pan, though. I kinda ruined one of ours.:rolleyes:

12-14-2008, 12:20 PM
does color have anything to do with water retention of soil? i have a project due tomarow i would be very greatful to anyone that can help me