The Effect of Soil Type on the Absorption of Heat and Water Evaporation

Researched by Cheyenne F.


The first purpose of this experiment was to determine which type of soil would absorb the most heat from light. 

The second purpose of this experiment was to determine which soil type would lose the most amount of water.

I became interested in this idea when I noticed the soil in my plants drying out and heating up and the plants withering from too much heat and water loss. 

The information gained from this experiment will help farmers, gardeners, and landscapers to decide what soil to plant in, which would avoid high temperatures, and prevent drying out.


My first hypothesis was that silt would absorb the most heat from light.

My second hypothesis was that sand would lose the most water during the experiment. 

I based my hypothesis on Master Gardener, Bonnie Johnsonís statement," Since silt is darker and finer than sand it preserves more water and absorbs the most heat from sunlight." 


The constants in this study were:

  •  The amount of soil
  • The amount of water added to soil
  • Water temperature
  • Purity of water
  •  Size and shape of aluminum pans
  • Temperature of heat lamp
  • The time the heat is given

The manipulated variable was the soil types.

The first responding variable was the increase in temperature of the soil. 

The second responding variable was the amount of water loss.

To measure the first responding variable I used a lab thermometer that measured in degrees Celsius.  To measure the second responding variable I used a triple beam balance to determine the change in mass of the soil.



 3   soil samples
 3 kg   soil
 3   aluminum pans 
 800 mL  water
 1  triple beam balance
 1  thermometer
 1  heat lamps
 2  quart jars
 1 Beaker



Separating Soil
1. Fill each quart jar with approximately 500 mL of tap water
2. Fill each jar with regular soil from own yard stir for three minutes
3. Leave for one day approximately 24 hrs
4. Separate soils (silt-on top, clay-middle, sand-on bottom)
5. Carefully pour out extra water
Drying Soil
6. Place one soil type in each aluminum container 
7. Heat in oven 300 F for about three hours (until dry)
8. Weigh soil (grams)-keep removing soil until all are exact weight 
Add Water
9. Pour equal amounts of water into each soil (100 mL each)
10. Weigh the soil with water and record
11. Determine how much weight was added
12. If possible, divide added weight by the total 100 mL of water (should give an approximate to how much each milliliter weighed)
Heat Lamps
13. Put heat lamp into position 
14. Turn on so it is same height above all soils
15. Leave on 12 hrs
16. Measure the weight after the given time
17. Use thermometers to measure the heat absorbed (leave for about 120-180 seconds) 
18. Determine how much water was lost (done in step 10) 


The first original purpose of this experiment was to determine which soil would absorb the most heat from light.

The results of the experiment were the sand, silt and potting soils all had an initial weight of 500g.  After I conducted the experiment the sand weighed 513.8g, retaining only 13.8 mL of water, the silt weighed 549.8, retaining 49.8 mL of water, and the potting soil weighed 556.1g retaining the most water, 56.1 mL of water.

The second purpose was to determine which soil type would lose the most amount of water. 

When I measured the temperature of each of the soils they were all in the upper twenties.  Sand was at 26 degrees C, silt was at 29 degrees C, and the potting soil was at 28 degrees C. 

View the table and graph.


My first hypothesis was that silt would absorb the most heat from the light.

The results indicate that the first hypothesis should be accepted because silt did absorb the most heat from the light.  The difference was quite small as potting soil was only one degree cooler and sand was only three degrees cooler.  I do not feel very confident that this data is meaningful because of the tiny differences.

My second hypothesis was that sand would lose the most water during the experiment. 

The results indicate that the second hypothesis should be accepted because sand did lose the most water during the experiment.  The sand lost 86.2mL of water compared to 50.2 mL for silt and 43.9 mL for potting soil.

Because of the results of this experiment, I wonder what would happen to the soil and water content if plants were growing in the soil. 

If I were to conduct this project again I would use more soil types and add more soil to the pans so they would weigh more initially.  I would also do more to insure the soils were totally dry before water was added.  I would use a much stronger source of light and would let it shine on the soil longer.


As you know, everyone around the world needs food.  There are people who grow their own on farms.  Soil, water, sunlight, and heat are all of the resources crops need to survive.  Without those there wouldnít even be any farms.  Soil is a very important resource for plants, next is water, and then the heat.  They all tie into agriculture.  We all need food to survive and thatís where these resources come in.


Soil, an extremely important resource, is the surface layer of earth that supports all plant life.  It is formed when forces grind or break rocks or other materials like it that are on or near the earthís surface.  Soil is the backbone of life.  We use soil for many different purposes.  It is used in our foundation for buildings, for plants and we use those for their roots and nutrients.  With that we get agriculture.  Without the roots or nutrients we donít get food.  Nutrients become depleted when the same crop is planted over and over.  We prevent this by planting different crops.


There are different types of soil, sand, silt, and clay; each of them has different layers.  The top layer is the A-horizon.  The A horizon is darker and looser.  It is full of nutrients and organisms.  The second layer is the B-horizon.  It is denser than the top and is full of organic and inorganic matter.  The third layer is the C-horizon.  The C-horizon is made up of mostly partially weathered rock.  The bottom layer is the bedrock.  The bedrock is just a solid sub surfaced rock.


Water is another important resource needed for agriculture.  Without water there can be no life.  Water is colorless, tasteless, and an odorless liquid.  It is a compound of hydrogen and oxygen (H2O). 


Everyday water is evaporated.  The sunís heat evaporates water from land, lakes, rivers, and the oceans.  Water floats up right past us without our knowing it because we donít feel it or get wet but there is still moisture in the air.  When it rains the water will be absorbed in to the land or wherever it fell.


Heat is the other thing needed to grow plants but with too much of it the plants will dry out and eventually wither.  Heat can come from many different things such as fire, sun, gas, friction, chemicals, and electricity.


Heat can be transferred into objects by radiation, conduction, or convection.  Heat, itself, follows the laws of Thermodynamics.  There are two laws, the first one stating, "Energy cannot be created or destroyed, it either transforms from one form to another or changes into a different type of energy," and the second law stating, "Heat will transfer from a high-temperature substance to that of a lower temperature." Heat is needed in plant life because in the cold plants arenít able to grow and in too much heat they dry out, thatís why an intermediate amount of heat is needed.


When you plant something the first step is to dig a hole, then you place the seed or the plant itself inside the soil, add water but not too much, cover it up with the remainder of the soil, leave it out in warm temperature, and from time to time water it.  Soil, water, sunlight, and heat are all you need to grow plants.  Agriculturally growing plants provides our food, which is basically our fruits, vegetables, and grain.
  • Cezairliyan, Ared           "Heat"    World Book Encyclopedia 1999
  • J.E.K.          "Thermodynamics" The New Encyclopedia Britannica
  • Johnson, Taylor J.        "Soil"    World Book Encyclopedia 1999
  • Keinath, Thomas M.     "Water"   World Book Encyclopedia 1999
  •                                       "Soil"    Earth at Risk: Degradation of the Land 


I would like to thank my parents, Mrs. Helms, and especially Mr. Newkirk.  I would like to thank my mother because she encouraged me to go through with the pressure of doing something Iíve never done before and helping me to conduct the complete experiment.  She emotionally supported me and helped with some of the difficulties I went through.  My dad helped with affording all of the materials I needed to buy. He also emotionally supported me when I conducted the experiment.  I would like to thank Mrs. Helms for helping me to get an understanding of what we were actually expected to do.  Most of all I would like to thank Mr. Newkirk for explaining to me how the process actually worked and giving me a better understanding of what we were doing.

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