Category: Uncategorized (Page 11 of 25)

Weekend Science Fun: Water Sloshing

This morning I asked myself a simple question:  “Why, when I’m carrying the cat’s full water bowl up the stairs, does the water slosh over at the top step?”

A question like this can often generate some interesting science.

Gather:

  • a couple of sturdy mixing or soup bowls with sloped sides, at least two different sizes
  • a straight-sided bowl, such as a casserole dish
  • water
  • metronome (optional)
  • water-proof clothing such as a rain jacket (if it is cold out or if the children can’t change clothes if they get wet.)
  • measuring cups (optional)

This is probably best done outside where a little spilled water won’t be a problem. First fill one bowl with water and see what happens when you walk with it held out in front of of you. Does the water begin to move back and forth? What happens when you stop?

Now compare that with a bigger or smaller bowl. Does more water go out over the edge with a big bowl or a small bowl? What about slope sides versus straight sides?

If you have a metronome, try walking at a constant slow pace versus a constant fast pace. See any differences?

You can actually make this more scientific by measuring the amount of water you put into the bowl and how much you have at the end with liquid measuring cups.

What we are seeing is the resonance, or the swing, of the water. When the swing gets big enough, over the edge it goes. This may not seem so important until you realize that the same sorts of forces are acting on the waves and tides of the oceans.

My son suggests I carry the water up the stairs in a straight-sided pitcher. Based on your studies, what do you think of that idea?

waves

Seed of the Week: Ash Trees

When I found these keys/seeds, technically samaras, I had no idea what current events they represent.

ash-samaras

The samaras are from an ash tree.

ash-tree

Several different species of ash trees grow in Arizona, all in the genus Fraxinus.

ash-bark

Ash trees are prized for their wood. In fact, ash wood is used for baseball bats.

ash-tree-leaf-1

Ash tree leaves are pinnate compound, which means they are made up of leaflets.

ash-tree-leaves-1

The leaves themselves are opposite each other, forming a V-shape with the main branch.

If you aren’t sure whether you have an ash tree, try this Ash Identification page.

The reason ash trees are in the news is because in certain regions they are being attacked by an insect. The emerald ash borer arrived in Michigan in 2002 and has been spreading and killing trees ever since.

ash-tree-borer

(Photograph Pennsylvania Department of Conservation and Natural Resources – Forestry Archive, Bugwood.org found at Forestry Images)

Although the adult beetles are lovely, the larvae or grubs feeding on the trees under the bark is fatal to the tree. People are concerned that the ash trees will experience a similar devastation as occurred with the chestnut trees and elm trees in the past. In fact there is now a great effort being put into saving seeds of the remaining ash trees in the regions effected.

The emerald ash tree borer website has more information about the beetle and its spread. The main thing they are asking people to do is not to move ash tree firewood from place to place, as that moves the beetle larvae that live inside the wood.

We are going to plant some of the ash samaras we found. Sounds like ash trees could use all the help they can get.

What kind of ash trees grow where you live?

Seed of the Week: Carob Tree

The mystery seed pods from last week have a wonderful odor.

mystery-seed-30

In fact they smell sweet and faintly reminiscent of chocolate.

These pods are from a carob tree, Ceratonia siliqua, which is grown as a landscape tree here in Phoenix.

carob-tree

The carob trees were originally from the eastern Mediterranean region. They grow well in areas with little rainfall.

carob-leaves

Each leaf is made up of 6 to 8 rounded leaflets.

carob-more-leaves

The tree retains its leaves and is green all year.

The pods start out green and then turn brown as they ripen. The hard seeds are inside.

To make carob powder, a chocolate substitute, separate the seeds from the pods. Roast and grind up the pods. Here in Phoenix, people harvest and mill both carob and mesquite pods. You can then use the carob powder to make brownies.

The carob seeds are used to make carob or locust bean gum, a thickener.

What an interesting plant!

Do you have a favorite carob recipe?

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