The Effect of Substrate on Temperature

Emily Condon, Claire Granlund, Samantha Robinson

††††††††† We hypothesized that temperature will be less variant in the water of Lake Michigan than on the sandy beach of Lake Michigan when looked at through the course of time because water has a higher thermal inertia.Water has the ability to hold heat better than land, which is a cause for many of our Wisconsin Weather systems.In an effort to study this property of water, we gathered the temperature of the water and the sand every half an hour.

We looked at standard deviation and concluded that water had a smaller standard deviation than the sand.We also tested whether substrate (sand or water) caused an effect on temperature over time.We found that sand did cause a decrease in temperature (P = 7.2276 x 10^-6).


Keywords temperature, water, air, standard deviation, thermal inertia



††††††††† Thermal inertia is the ability for a volume to hold temperature (Mitra & Majumdar, 2004).Mitra and Majumdar (2004) did mapping of thermal inertia in India and over the ocean.Using a combination of tools, such as satellites and radiometers, they were able to map this area.This was to look for anomalies in temperature.As they studied the patterns, they found that the ocean had much better thermal inertia, meaning it holds heat better than land.This is what they expected from this mapping.They focused more on the points that were outliers or did not fit the trend (Mitra & Majumdar, 2004).

††††††††† Nasipuri, Mitra and Majumdar (2005), did a map of part of India.This map was different from what they did in 2004.This map was used as a geologic map, instead of just a temperature map.Because they know that temperatures can indicate geologic features, they could use it as an effective and efficient way to map out geological areas (Nasipuri, Mitra, & Majumdar, 2005).

††††††††† Nearing (2012) used thermal inertia to determine how much water was at the surface of the soil.He stated, the more water there is at the surface, the better it can hold heat.This was developed into a method to use temperature to measure the amount of water at the surface.They took measurements twice during the day and the soil with more water would be less variable than the soil with little to no water (Nearing, et al, 2012).††††††

††††††††† We hypothesized that temperature will be less variant in the water of Lake Michigan than on the sandy beach of Lake Michigan when looked at through the course of time because water has a higher thermal inertia.


Materials and Methods

††††††††† We collected the sand and water temperatures on Tuesday November 5th, 2013 from Bradford Beach in Milwaukee, WI.We marked each spot with a flag so we could return to the same spot.We took the temperature of the water every half an hour in 5 different locations from 1500 to 1830 with a water thermometer.We also took the temperature of the sand in 5 different locations, at the same time as the water with a Syntec thermometer.

††††††††† We found the standard deviations for sand and water temperatures, and preformed a type one, two-tailed T-Test on Excel© for Windows 2007©.




Table 1: Flag Number and Location.The locations were measured by using the distance they are away from shore.All sand locations were taken on the surface of the sand.All water locations were taken one inch deep.The shoreline of Bradford Beach that we took our data from was the shoreline near the volleyball nets.

Flag Number


1 (sand)

10 meters 32 centimeters

2 (sand)

7 meters 0 centimeters

3 (sand)

3 meters 15 centimeters

4 (sand)

5 meters 72 centimeters

5 (sand)

1 meter 64 centimeters

6 (water)

1 meter 18 centimeters

7 (water)

2 meters 0 centimeters

8 (water)

3 meters 9 centimeters

9 (water)

1 meter 17 centimeters

10 (water)

2 meter 30 centimeters













The mean of the sand temperature was 11.87 degrees Celsius with a standard deviation of 0.17.†† The mean of the water temperature was 11.51 degrees Celsius with a standard deviation of 0.10 (Figure 1).

The mean temperature for sand and water through time are both decreasing, however the water temperature is less variant than the sand temperature (Figure 2). ††We preformed a type one, two-tailed T-Test and found that sand temperatures were significantly different than water temperature (Fig. 1, P = 7.2276x10^-6).



Figure 1.Mean (+/- S.D.) of temperature in sand and water.


Figure 2. Mean of temperatures in sand and water over time.



††††††††† In this study, temperature was taken at five different locations in the water and five different locations in the sands of Bradford Beach on Lake Michigan.

††††††††† The temperature had less variation in water as compared to sand.Over the 3 and a half hour time span, the water temperatures had less of a change than the sand temperatures in the spots we marked and tested.This supports the idea of water having a higher thermal inertia than the sand because the water was less variant in temperature showing that it held on to its temperature better than the sand did. Mitra and Majumdar (2004) found this when working on a larger scale as they noticed that the ocean had a higher thermal inertia than sand.

††††††††† Water has a higher thermal inertia than the sand, meaning that it takes a lot more to increase the temperature of one cubic centimeter of water one degree than one cubic centimeter of sand.Especially being the Lake Michigan is such a large body of water; this process takes a very long time.This is why the lake is still cold in the middle of summer and the sand feels warm on our feet.The sand is able to heat up (and cool down) much quicker than water.

††††††††† One constraint we ran into with this project was time.We tried very hard to coordinate three college studentsí schedules, but we were only able to all be in the same place at the same time for the duration of 3.5 hours.In addition, we only tested points on one part of Lake Michigan on one day.

††††††††† If we were to repeat this experiment, we would have done this same experiment on either many different parts of Lake Michigan, or on the same part of Lake Michigan over several days.Something that would be interesting to test would be the effect of humans swimming in the lake on the temperature of the lake; would this cause an increase or decrease in temperature?It could cause a slight increase in temperature for two reasons: mixing the water could cause a higher temperature reading by bringing the warmer water up and people are warm, so this might increase the temperature slightly if there were a lot of people in the water.



Mitra, D. S., & Majumdar, T. J. (2004). Thermal inertia mapping over the Brahmaputra basin, India using NOAA-AVHRR data and its possible geological applications. International Journal Of Remote Sensing, 25(16), 3245-3260. doi: 10.1080/01431160310001632701.

Nasipuri, P. P., Mitra, D. S., & Majumdar, T. J. (2005). Generation of thermal inertia image over a part of Gujarat: A new tool for geological mapping. International Journal Of Applied Earth Observation & Geoinformation, 7(2), 129-139. doi:10.1016/j.jag.2005.02.002

Nearing, G. S., Moran, M., Scott, R. L., & Ponce-Campos, G. (2012). Coupling diffusion and maximum entropy models to estimate thermal inertia. Remote Sensing Of Environment, 119222-231. doi:10.1016/j.rse.2011.12.012