Plants need soil, so asking what type of soil is in the garden is the first question a gardener should ask. The following experiment done by the grade 5 science students, is based on the Shake, Rattle and Roll experiment in the Junior Master Gardener Leader Handbook. Purpose: To identify the amounts of different sizes of soil particles that make up a soil’s texture in our school garden. Time: 20 minutes plus 24 hours to settle. Materials: clear plastic cups, plastic spoon, soil, water, permanent marker (The book calls for jars, but I try to use the cheapest and safest materials possible. A clear plastic cup with a plastic spoon to stir worked very well instead of a jar but I knew our soil was very sandy. If the soil is mainly clay, then a jar with a lid so the soil can be thoroughly mixed and suspended in water would work better.) Procedure: Students worked in pairs to complete the following
Use a permanent marker to label a cup so each group knows which cup belongs to which group.
Dig about 6 inches into the soil for the soil sample. Do not take the soil from the surface. Half fill the plastic cup with soil.
Add enough water to fill to within half an inch (1.25 cm) of the top of the cup.
Stir carefully with the plastic spoon to thoroughly mix the water and soil. Mash lumps against the side or bottom of the cup, then stir again until the soil is completely suspended in the water.
Place the cup on a solid surface. Do not disturb it for 1 minute.
Use a permanent marker to mark the side of the cup where the layers are.
Leave the cups for 24 hours without moving or disturbing it.
Observe and measure any changes in the layers. Record the results.
Particles floating on the top of the water are bits of organic matter.
The top layer of soil is clay, the smallest, lightest particles.
The next layer down is silt.
The bottom is sand, the largest and heaviest particles.
In the photo below, the clay layer is not visible. It was a very thin light tan colored layer on top of the darker silt layer.
Layers of Soil
Results: Each student created a graph comparing the different layers of soil particles. The graph below was done by a student in the class.
Depth of Layers of Soil
Conclusion: We discussed how knowing the particle size and soil texture would influence our decision about where to have a garden and what to grow in the garden.
On Earth Day, the grade 5 science classes set up the following experiment using 3 bottle biology terraqua columns from earlier in the year. The experiment is based on a suggested activity, Polluting Your Planet, in the Junior Master Gardener Teacher Guide.
The bottle represented the Earth. Earth is a closed system that includes the following:
atmosphere – the gases that surround the earth (the air around the plants)
lithosphere – the solid part of the earth including the soil (the soil in the top part of the bottle)
hydrosphere – the water on earth (the water in the soil and in the lower part of the bottle)
biosphere – the living things on earth (the plants in the soil and in the water)
Purpose - To investigate the effects of pollutants on the biosphere.
Sample Prediction - from 2 students in the class.
salt water - It will stay alive.
oil – It will die.
acid rain – It will die.
salt water – will affect the water under it. The plant will survive but it will kill the one on top
oil – Death for all !!!
acid rain – will burn the leaves and kill the plants
3 bottle terrarium – each with water and a plant in the lower section, a plant and soil in the top section
salt solution (1 Tablespoon in 2 cups of water to represent incorrect fertilizer applications)
oil (3 tablespoons of motor oil to represent pollutants from fossil fuels)
vinegar solution ((half vinegar and half water to represent acid rain)
plastic bags to seal each of the bottle containers.
Pour salt water solution on the soil in bottle #1.
Pour oil on the soil in bottle #2.
Spray vinegar and water solution on the plant and soil in bottle #3.
Enclose the top of each bottle terraqua column with a plastic bag, so each bottle represents a closed system with atmosphere, lithosphere, hydrosphere and biosphere like the Earth. Seal the bag.
We left the plants for 2 weeks and made observations at the end of the time.
Sample Student Observation - from the same 2 students.
Salt water – no effect on plant in the water but only a couple leaves left.
Oil – The plant on the top is dying slowly but did not affect the plant in the water.
Acid rain – Both plants are slowly dying.
salt water – it sucked up all the moisture from the leaves
oil – leaves are losing their color and gradually falling off and dying
acid rain - killed every thing!!!!!!!!!
Sample Student Conclusions - from the same 2 students.
Student #1: All liquids effect the out-of-water plants, but not all liquids effect the plant in the water.
Student #2: Pollution can kill every kind of plant, so do God’s will and stop polluting!!!!!