Part 1: Soil Horizons Formation
•1 Italian salad dressing spice packet
•1 cup oil
•1 cup vinegar
•1 clear jar
•Watch with a second hand
Soil Formation & Edible Horizons Worksheet
Part II: Gallery Walk
•Soil Information Cards
Part III: Edible Soil (per pair of students)
•1 Ziploc bag with 4 chocolate cookies
•1 Ziploc bag with 2 chocolate graham crackers
•1 Chocolate pudding cup
•1 Vanilla pudding cup
•2 Clear plastic cups
•1 paper cup with 1/3 cup of chocolate chips
In this hands-on fun activity, students learn what a soil profile looks like and the composition of soil. Students are introduced to the five soil forming factors and soil horizons.
Part I: Soil Horizons Forming in the Blink of an Eye
Soil horizons form over hundreds, thousands and even millions of years. It is a process we can see after it has happened, but not in action. This demonstration will help show students how horizons are formed – a sort of time-lapse soil horizons.
1) Explain to students: Before soil horizons form they start as a mix or jumble of solid and organic materials. Volcanic eruptions or floods are examples of these mixing events. A mass of similarly mixed materials are spewed out and with the passage of time, and the effects of climate, organisms, parent material, time and topography (CLORPT), soil horizons are formed.
2) Combine the salad dressing spice mix, oil and vinegar in a clear jar.
3) Vigorously stir the salad dressing and watch the dressing mix up. This is equal to a volcanic eruption or flooding event.
4) Place the dressing where everyone can see it settle out.
5) Using a watch, announce the passing of every 30 seconds to the students and have them observe and record what is happening at each interval on their Soil Formation & Edible Horizons Worksheet. Each 30 seconds is equal to approximately 100 years of actual soil horizon forming. As the dressing settles out it will show “virtual” soil horizons forming.
6) Explain to students that the ingredients in the jar represent the horizons in soil. The spices are the parent materials, the lightest layer is top soil, etc.
Part II: Student Gallery Walk
1)Using the Soil Information Cards, stage the room with cards hung on the wall in sequential order. There are two different sets of cards the first 1-9 describe the soil horizons and their composition the second set 1-8 describe the soil forming factors in detail (CLORPT), the first three cards in each set are identical to provide some background information.
2) Have students partner up, one partner will go to the soil horizon information cards and the other will go to the soil
formation factors cards. Depending on class size you may want to have two sets of each of the cards.
3) Students should fill in their Soil Formation & Edible Horizon worksheet with the information they read on the cards. Once
they have completed their set of cards and notes, they should meet with their partner and share what they learned, taking
notes on their partner’s card sets.
4) Once students have collected all of the information, have them answer the review questions in preparation for the
1) Explain how some horizons support plant growth better than others and how the color of the soil signifies the nutrient
availability within the soil.
2) When looking at a soil profile, how do you distinguish horizons from one another?
Part III: Edible Soil Horizons
1) Working in partners, one student from each partner group should collect the supplies from you. Make sure to
remind students that they may not start eating their Soil Horizons cup until you have approved their work.
2) Provide each set of students with: 1 ziploc containing 4 chocolate cookies, 1 ziploc with 2 graham crackers, one
chocolate pudding cup, one vanilla pudding cup, 2 clear plastic cups and one paper cup with 1/3 cup of chocolate
chips. (Older students can read through the directions on their worksheet to complete the activity, younger grades
may have to do the activity as a class one task at a time.)
3) When all students have the supplies, have each partner grab one of the ziploc bags containing food items, the
partner with the chocolate cookies will want to break up the cookies into large chucks by squeezing them in the
bag. The partner with the graham crackers will want to break it up into tiny pieces by squeezing them in the bag.
4) Next, each student will grab one of the clear plastic cups, this will hold their soil profile. Make sure to instruct
students not to mix up their ingredients as they are placing each item in the cup.
5) In the bottom of the cup, each partner group will divide the chucks of chocolate cookies from the ziploc bag and
place them in their cup.
6) Then, divide the chocolate chips that you have in the paper cup amongst your cups.
7)The vanilla pudding will be next, divide the pudding cup evenly between you and your partner and place in your
8) Add the chocolate pudding next, dividing it up the same way you did with the vanilla.
9) Then, divide up the crushed graham cracker and add it to the top.
10) Now, using what you know about soil layers, label each layer with the horizon it represents in order. Also,
provide labels such as top soil, subsoil, parent material, etc.
11) Have students raise their hand once their soil profile is complete with labeling for approval from you to eat it.
12) Review each soil profile and provide students with a couple of organisms(gummy worms) and a spoon for their
soil! Enjoy your soil profile!
For instructions, please download our PDF