This week, we took a look at Case 2 in the free curriculum The Great Plant Escape, and learned lots about soil.
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First, I showed him how much of the total Earth actually grows all the food that humans and animals are dependent on. We took a kiwi (we were out of apples!) and cut it into quarters.
We took away 3/4 to represent the water on the earth's surface.
We cut the remaining quarter in half again and took away one of the eights to represent the part of the land that is unusable for human habitation.
The remaining eighth, we cut into 4 pieces and took away three of them to represent areas unsuitable for growing food, because of poor soil or other factors such as development.
The last tiny 1/32 of the kiwi, we peeled and I explained to D that this teeny piece of peel represents the area of land available in total that the entire earth depends upon for growing food. Mind-boggling, isn't it?
Next, we looked at what makes up soil itself. We learned that soil is made up of rock particles, water, air and organic matter such as decaying leaves. We learned that soil scientists describe soil types by texture...clay, sandy, loamy, and so on. If it's too high in one component, it can affect the ability to grow life properly because it might not drain properly or contain enough nutrition to help plants grow. The combination of different sizes of the particles make a big difference too.
Think of the sizes this way:
We can finally get some dirt up out of the ground, so we got a handful and examined it. Good soil will squish together in your hand but can be crumbled again afterwards, and you should be able to see pieces of plant matter in it. If it won't hold together in the first place when you squeeze it, or will clump but not crumble, you need to make some additions to make it workable.
D's conclusion was that our soil looks pretty good for growing plants, but it could maybe use some extra drainage in the parts of our land that have slate slabs not far under the surface.
I reminded D of our discussion about what plants require to grow, then we read that the three nutrients plants need from soil are nitrogen (for leaf growth and dark green colour), phosphorous (which encourages plant cell division so they grow flowers, roots, and seeds), and potassium, which helps protect plants from disease and is needed to make chorophyll. I knew that D had understood when he compared it to getting the vitamins you need out of food in humans.
There's a lot more to learn, so we'll share the next part in another post soon.
I also found a fantastic resource for my US readers from Nutrients For Life. They will send you, free, a homeschool curriculum for elementary level,middle school level, or high school,with fertilizer samples, lesson plans, and more. Julie, their education specialist, was good enough to send me pdf versions of the curriculum so I could look it over before sharing with you, and it is so well put together that M, 13 has asked to try it out. There are even tests included if you need to grade for your state.
Air Pressure from Suzy Homeschooler
What is soil? Experiments and activities for kids from The Usual Mayhem
Learning about nature with toddlers and preschoolers from P is for Preschooler
Simple Science: Mentos and Soda Geyser from The Joys of Boys
Preschool Books about Recycling from Stir the Wonder
Engineering Egg Drop Project from Lemon Lime Adventures
Link up your science posts below! We read and pin them all.
Linky code: April 19th