What Do Plants Need to Live?
People like you and I need a few things to live — we need healthy food, we need water, and we need air. Plants, though, are a little different than you and me. They need food and water, but they also need sunlight to live. Plants use sunlight as a way to make energy to grow.
Plants and animals, including people like you and me, breathe in air. But plants use a different part of the air than you or I do. We breathe in a part of the air called oxygen. We use the oxygen that we breathe in the air to feed the blood in our bodies. Plants use a different part of the air, a gas called carbon dioxide. We breathe in oxygen and breathe out carbon dioxide. Plants do just the opposite — plants breathe in carbon dioxide and breathe out oxygen. So the oxgyen you’re breathing now probably came from a plant. Thanks, plants!
Plants also get food from the soil. To live, they need a certain chemical that you can find in the soil. This chemical is called nitrogen. You have nitrogen in your body, too, but your body can’t use it. So when you get nitrogen in your body, your body gets rid of it. How does it do this? It leaves your body through pee and poo. All the stuff in pee and poo is stuff that your body can’t use. That’s why pee and poo is sometimes called “waste” — because it’s something leftover that you can’t use.
But because pee and poo are full of nitrogen, plants love it! If you’re a tree and a dog pees on you, are you happy or sad? You’re happy, because that pee is full of nitrogen that you can use to eat. The same is true with poo. In fact, farmers take poo from their cows and spread it across their fields to make the plants in their fields grow better. This is called “fertilization” — the farmer is using cow poo to make it easier for plants to grow in the field.
Please correct your inaccuracies:
Plants respire (breathe) the same way as animals do, they take in oxygen (to release their food energy) and give off carbon dioxide (as the food is “burned” ).
Plants do not get food from the soil (even though fertilizer is mistakenly called “plant food”). They get nutrients such as nitrogen from the soil and use these to make their own food through the process of photosynthesis. This is the process where plants take in carbon dioxide and give off oxygen.
As a science teacher, I spend a lot of time trying to get kids to use words correctly.
Thanks,
Fran Ludwig
K-5 Science Coordinator
Lexington (MA) Public Schools
Comment by Fran Ludwig — January 31, 2008 @ 8:07 am
Yo Fran, thanks for weighing in with the straight poop, but I have to say, the way you’re approaching this suggests to me that you’re the kind of teacher that made me hate science when I was in elementary school.
This post was written for a five-year-old. Obviously it glosses some stuff over. Do you use words like “photosynthesis” with kindergardeners?
Comment by admin — January 31, 2008 @ 8:24 am
In fact, Fran, there are lots of plants (like algae) that don’t need soil, and hundreds of species of plants that don’t do photosynthesis (they are parasites of photosynthetic plants). So if you really want to get technical, and I know you do, your explanation isn’t totally accurate either.
Comment by jeffrey — January 31, 2008 @ 8:51 am
Fran, thanks for adding your comments - they were quite helpful. Yes, actually, current educational theory says you should be using words like photosynthesis with 5-year-olds; there’s no reason to “dumb down” science for kids if it involves explaining things inaccurately such that they’ll have to unlearn it later. Science is such a fascinating subject, and I feel sorry for anyone who was turned off to science as a kid.
Comment by Colleen — April 21, 2008 @ 7:45 am
There is a huge difference between dumbing it down and using language that’s appropriate for their age. If they can’t understand what you’re talking about in the first place, they’re never going to learn it.
Comment by admin — April 21, 2008 @ 8:10 am
Hi,
I really enjoyed the comedy show after the “Science” hour. Thanks! Deanna
Comment by Deanna — April 22, 2008 @ 3:44 pm