Use chemistry to change the colors in a bouquet of flowers.

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How do plants move water and food without a heart for a pump?

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This week's experiment is the result of a marvelous trip we took yesterday to the Okefenokee National Wildlife Refuge.  Nancy spotted an amazing number of wildflowers, which I photographed, and am now trying to identify.   Luckily, the flowering plants can be divided into two groups, the Monocotyledons and the Dicotyledons, often known as Monocots and Dicots.  To learn about sorting plants into these two groups, you will need:

- leaves and flowers from different kinds of plants

First, lets take a look at those long, complex names.  What in the world does Monocotyledon mean?  Or Dicotyledon?  Notice that they both have the same ending.  A cotlyedon is also known as  seed-leaf.  This is the first leaf that emerges from the seed.  Next, take a look at the first part of each word.  Mono- means one, and Di- means two.  Once you know that, then the difference between the two groups is easy.  Monocots have a single leaf when the seed sprouts, while Dicots have two.  

Knowing that, it is easy to tell the difference between the two, if you grow them from seeds.  If you have ever planted a garden, then you can probably recognize plants from both groups.  Corn, onions, and garlic have a single leaf when they sprout, which makes them monocots.  Squash, beans, cucumbers, and most other garden vegetables have two leaves when they sprout, so they are dicots.

That is great if you have the time to gather seeds from your wildflowers, and then wait for them to sprout.  (Do NOT collect seeds or anything else in National Parks or Wildlife Refuges!)  Luckily, there are other ways to separate the two groups.

One "test" that usually works is to look at the veins in their leaves.  Most monocots have veins that are parallel, running side by side.  To see an example of this, look at a blade of grass.  Most dicots have leaves with veins that form networks.  Look at the leaf of lettuce, or a leaf from an oak or maple tree.  Notice that I said "most" for both.  This is not an absolute test, but it will usually put you on the right path.

Another test involves cutting the plant's stem.  (Do NOT chop up plants or anything else in National Parks or Wildlife Refuges!)  Use a sharp knife to cut through the stem, and then examine it with a magnifying glass or microscope.  You are looking for the vascular bundles that carry food and water through the plant.  For dicots, the vascular bundles are arranged in rings or lines.  For an easy example of that, chop some celery. The "strings" in the celery are the vascular bundles, and you will find them lined up in a nice row.  That tells us that celery is a dicot.  For monocots, the vascular bundles are spread through the entire stem.  While you are chopping your celery, chop some hearts of palm or some bamboo shoots.  Neither will have that distinctive row of vascular tubes, since palms and bamboo are both monocots.  Mix both of these with the dicot lettuce leaves, and you are well on your way towards a delicious salad.  As you add other yummies to your salad (cucumbers, tomatoes, onions, carrots. etc.), try to determine which are monocots and which are dicots.

For my purposes, the best test was to look at the plant's flowers.  Since the flowers are what we were photographing, this is just what I wanted.  All you have to do is count the number of petals, sepals, stamens, and pistils.  

For monocots, these will be in multiples of three.  If you count the number of petals on the flower, it would have either three, six, nine, or a multiple of three.  The same is true for the stamens (the part that produces the pollen), and the sepals (the leaves around the base of the flower.  Be warned that this can sometimes be difficult to see. 

For dicots, the parts will be in multiples of four or five, so a dicot flower might have four petals, five petals, eight, ten, etc.  Again, be warned that plants can be tricky.  Some plants may have one or more tiny petals that are hard to find.  

OK, so now you are ready to test your new knowledge.  You could head for your local swamp, but there is a much easier field trip that you can make.  Head for your local grocery store.  Look through the produce section, and you should find a wide variety of both monocots and dicots.  Most groceries also have a section for live flowers, which will give you a great chance to count some petals.  Your local garden shop will also have quite a few examples from each group.  Even simpler, go out in your yard.  A close look at your lawn should give you plenty of plants to work with, although most of them will not be as tasty as what you would find at the grocery.

Have a wonder-filled week.

How do plants spread their seeds to new areas?

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Thoughts on Trees

This is another post that comes from the Science Photo of the Day. It worked well there, but has great potential for a full blown Experiment of the Week activity. To try this, you will need:

- a plant or some seeds
- a pot to grow the plant in
- potting soil
- a scale to weigh the plant, pot, and soil

We will explore how plants grow, by growing a potted plant. You can use a plant from your local garden shop, or you can plant seeds from your favorite plant.

Start by weighing the pot. Then put the soil into the pot and weigh it again. Finally, add the plant or seeds to the pot, and weigh it one more time. This will let us calculate the weight of the plant (weight of everything minus weight of the pot and soil) as well as the weight of the soil (weight of the pot and soil minus weight of the pot.) Be sure to write everything down, as we will need that information later.

Then all you have to do is get the plant to grow. Give it water, and plenty of sunlight, but don't add anything else. As the plant gets larger, weigh it again. You should find that it has gained weight, even though you have not added any soil. Where did that extra weight come from?

To find out, start by looking at trees. Don't just think about trees. Look out the window, or even better, go outside. Notice how big trees are. Wrap your arms around the trunk, and get a feel for how strong it is. Think about how much wood is in that tree. Think about all the leaves that it produces and drops on your lawn. Think about how heavy those leaves are when you rake them up and haul them away.

Where does all that stuff come from? Your first thought is probably that it comes from the soil. After all, our bodies build up their mass from the food that we eat, and plants eat by taking in nutrients from their roots, don't they? Think about that for a minute. Look at the ground around the tree. If the tree had removed enough matter from the soil to build its trunk and branches, there would be a huge hole around the tree. Then think about your potted plant. It gained weight, which did not come from the soil in the pot.

Plants are not like us. They don't take in food. Instead, they make their own food, through the process of photosynthesis. To do that, they need energy, which they get from sunlight. They also need hydrogen, oxygen, and carbon as the chemical building blocks to make their food. They get those chemicals from water (hydrogen and oxygen) and carbon dioxide (carbon and oxygen.) During photosynthesis, these chemicals are recombined to form sugar. That sugar can be used as it is to provide energy for the plant, or it can be converted into other substances such as starch and cellulose, which make up the trunk, branches, roots, and leaves of the tree. Almost the entire tree is made of the chemicals from rain water and carbon dioxide from the air, and the same is true for your potted plant. It is also true for apples, peaches, strawberries, etc. When you think about it, even chocolate is made from plants. The sugar from plants, and so is the cocoa. That means that chocolate is mostly made up of sunlight, water, and air! Sounds yummy to me!

Have a wonder-filled week.

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Getting to the Root

Clone a Plant!

This week's activity is one that I use for Schoolyard Ecology workshops. It is a great warm up for getting people to slow down and really look at the world around them. To try this, you will need:

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The idea for this week's experiment comes from my wife, Nancy. I was sitting here at the computer, trying to decide what to write about when Nancy made a comment about how good the flowers on the table smelled. Nancy loves flowers, and always has lots of them around the house. That one whiff and this week's newsletter practically wrote itself.

If you are lucky enough to have flowers around your house, take a few minutes and smell them. If you don't have flowers around the house, you should be able to find a variety of flowers at your local grocery, hardware store, or nursery. Once you are surrounded by the flowers, take the time to sniff them, one by one. Keep track of your observations (sniffservations?) What did you notice?

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This week's experiment is a result of preparing for next week's experiment. It began as an experiment with insects, but it was getting too long, so I chopped it in half. (The experiment, not the insect.) This week, we will look at the amazing variety of insects that can be found almost everywhere.

You will need:
- an umbrella
- a magnifying glass
- some shrubs or bushes

The first thing to do is to carefully examine the bushes. You want to be sure not to disturb a nest of wasps or bees. Also check for bird nests. Since this experiment is not about the birds and the bees, we want to be sure that we don't bother them and they don't bother us.

Next, open the umbrella. Hold it upside down, so that it hangs down from your hand instead of being over your head. Hold the umbrella under one side of the bush. With your other hand, grab the bush and give it a good shake. Now you know why we checked for bees. It is hard to do science experiments while you are running from an angry bee. The bowl shape of the upside down umbrella makes a perfect way to catch falling creatures. After a few good shakes, you should have some leaves, but you should also have quite a few other things. Place the umbrella on the ground and grab your magnifying glass.

Depending on where you live, what the season is and which bush you picked, you probably got several kinds of insects. I say insects, not bugs, because while bugs are insects, not all insects are bugs. Bugs are a specific group. Their mouth is a long, sharp tube, like a drinking straw. Most of them feed on plant juices, so you probably have some bugs in your umbrella, but you probably have insects from other groups too.

You may also have collected spiders, lizards, frogs, or other creatures. Examine them carefully. We don't want to hurt them, and we don't want to disturb any that might bite you. As you examine your catch, you may want to write down notes, draw pictures or take photographs to help you keep track of what you found.

When you are done, tip the umbrella over the bush to put them back where they belong. Then move to another bush and try it. You will find that the insects and other creatures will vary from bush to bush. Different kinds of bushes are eaten by different kinds of insects. Even with the same kind of bush, location makes a difference. You will probably get different things from a bush in the sun than you do from a bush in the shade.

When you are finished, be sure to tip the creatures back into their bush. If you put them on the wrong bush, they might not find anything to eat. If you forget to put them back, the next time it rains, you may get quite a surprise when you open your umbrella.

A neat trick for predicting the number of slices in an orange before you slice it.

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