Growing With Science Blog

This week our science fun has been inspired by a book that just came out, Planting the Wild Garden by Kathryn O. Galbraith and illustrated by Wendy Anderson Halperin. See Wrapped in Foil blog for a full review.

Planting the Wild Garden is a beautifully illustrated picture book that is a delightful introduction to the ways wild seeds move around (are dispersed).

Plants can’t move once they start growing, yet we see plants almost everywhere. How did they get there? Most travel as seeds. Seeds have many different ways to spread and scatter.

In this video from the Life of Plants by David Attenborough we get to see some marvelous footage of the amazing ways seeds move. Note: there is a pop-up ad.

Activity 1. Investigate seed structure and movement through observation.

Here at Growing with Science we have a regular feature called Seed of the Week. Take a look at some of the seeds and guess how they might be transported from place to place. For example, check the Chinese elm seeds (samara) with their tiny wings. Don’t they look like they could fly?

Go outside and look for seeds, particularly in the fall. Observe them and try to figure out how their structure helps them get from place to place. Look at them through a hand lens. Toss them in the air. Blow on them. Put the seeds in a puddle. See if they will stick to your sleeve. Think about where you see seeds and how they got there.

Activity 2. Floaters

As you saw in the video, seeds like the sea bean can float from place to place. They don’t have to be in a big body of water like the ocean either. A small trickle created by a downpour of rain may be enough to float seeds away.

Gather:

• Large bowl, sink, tub or aquarium to fill with water
• Seeds or fruits to test for ability to float:   coconuts, cranberries, a pinto bean or other dried bean, etc.

Predict what will happen to each item and then test each item. Let the seeds or fruit float as long as possible to show that they might reach land without sinking. You might want to cut open a cranberry to show the seeds inside.  (Remember that cranberries are harvested by floating them in ponds). Does a cut cranberry float?

More advanced activity:

Scientists in Hawaii needed to know how plants arrived on the islands in order to protect native species and prevent introductions of invasive species. A scientist named Henry Guppy placed different seeds in jars of seawater for several months to see how long they could float. Design your own experiment to test which seeds float in your area and investigate how they do it.

Have you ever gone to the beach or the shore of a lake? Look for seeds on the shore that were carried there by water.

Activity 3. Flying Seeds

Most of us have seen seeds flying in the air at one time or another. Dandelions, milkweeds, maple keys and cottonwoods are just a few examples of trees with seeds that ride the wind.

This slide show shows how humans can help cattail seeds disperse.

Dandelion and cattail seeds fly with structures that are like tiny parachutes. If you are interested, try investigating parachutes.

Advanced:
Design an experiment to test how far a dandelion seed can fly. How would you measure it?

Maple keys are so interesting that scientists take high speed movies of them to discover the secrets of their movements. According to this study, the keys produce swirling air like mini-tornadoes while they spin. Here the seed has been dropped in oil to make the whirls easier to see.

Do you see the tiny swirls that form over the end of the “tail” part of the key? Cool!

For more about maple key science, try these links:

Whirling Wonders

NASA Maple Seed Aeronautics

Maple seed science -some of links are broken, but go to Exploring Science and Design with a Maple Seed and click on the words under the pictures to find instructions on how to make the origami and other models to test.

Animals also transport a lot of different kinds of seeds. Whenever an animal, such as a bird, eats a juicy bit of fruit like this pyracantha berry, it ingests the seeds. The seeds end up on the ground later on. Other animals, like squirrels, may bury seeds and forget where they are.

Some seeds, like burdocks, hitch a ride by being sticky or latching on the fur of mammals.

We often think of big animals moving seeds, but tiny ones move a lot of seeds, too. Check for a related post at Wild About Ants for information about ants and seed dispersal.

Finally, by far the coolest are the seeds that pop out of the pods and shoot away. Plants with this kind of dispersal include jewelweed, lupines and Scotch broom. See if you can find a plant that does this and try it out.

And don’t forget to pick up a book about seed dispersal, such as Planting the Wild Garden, to learn more and inspire your own investigations.

Reading level: Ages 4-8
Hardcover: 32 pages
Publisher: Peachtree Publishers (April 1, 2011)
ISBN-10: 1561455636
ISBN-13: 978-1561455638

Book was provided for review purposes.

Winter is not always the best season for botany lessons outdoors, but there are still plenty of fun things to explore indoors when it comes to plants.

Today we are going to investigate how plants survive harsh periods when they can’t grow, such as periods of cold weather or drought.

Gather:

• Storage roots:  carrots, preferrably natural with tops (not baby carrots)
• Bulbs: like onions
• Seeds:  dried bean seeds would work well, as well as packets of carrot and onion seeds
• Perennial fruit:  such as blackberries

Or at least gather some pictures.

Look out the window on a winter day. Where are all the plants?

Plants have different life cycles. Some plants are annuals, meaning they complete their life cycle in one growing season. At the end of the season the plants release seeds that fall to the ground. Take a look at the seeds and examine the outer layers, called seed coats.

The seed coat keeps out decay organisms and helps the seeds survive until conditions are right for growth.

A few of our common edible plants are biennials. Plants like carrots and onions require two growing seasons to complete their life cycles. In the first growing season they store up food in the root or bulb. The root remains protected underground over winter. The second year the plants utilize that food to grow flowers and produce seeds. (Show the roots, bulbs and seeds).

Try planting a carrot root or onion bulb. What do you think will happen? (Note:  to save food, simply plant the carrot top and the bottom, white part of a green onion.) See if you can grow the plants until they flower and produce seeds.

Other plants are perennials, which live for three or more years. Of these, some survive the winter as storage structures like bulbs, rhizomes or corms. Daffodils are bulbs, crocuses are corms and irises are rhizomes.  Bushes and trees have woody stems that survive above the ground as well as roots underground. Strawberries, blackberries, grapes and peaches all come from perennial plants.

If you get a chance, go on a walk and look for plant seeds, storage roots and other overwintering plant structures under the leaves and snow.

For a free gardening poster that covers the basics of a plant cycle, go to Welch’s Harvest Grants for school gardens at Scholastic. If you click on the parents’ side- look at the right hand column for a “How Does Your Garden Grow” poster in .pdf format, as well as a garden activity sheet (a maze and seed marker template.) Note:  if you use the poster, you might want to mention the bean seed is found in the green bean fruit and show an example.

For more plant activities, try Kitchen Scrap Gardening activities at GrowingWithScience.

(which reminds me, I should really start working on that again )

Let me know what you find out!

Right in time for Mother’s Day, we have a hummingbird nest filled with two baby hummingbirds outside our upstairs front window. There is a creeping fig vine that climbs over the front door and this is the fifth time hummingbirds have nested on it.

Do you think that is the mother bird or a baby? We know from experience that it is a baby because the mother’s beak is much longer relative to her head size. As you can see, the mother bird is a bit messy about the bird droppings.

I’m afraid this isn’t the best photo. The circumstances are less than ideal to take a photo and I didn’t want to disturb the chicks in any way. The nest is incredibly tiny and very hard to spot.

Take a look around your neighborhood and see if you can locate any birds making nests. You might want to take photos and make records of what is happening to the nest over time. Always be sure to respect the birds and stay well out of their way as much as possible.

If you want more opportunities to watch birds, you can put up bird nest boxes. Take a look at Nestwatch for ideas and projects.

If you can’t find a nest to watch, check the Cornell Lab of Ornithology Nest Cams.
If you have a sensitive youngster, be aware that the owls and hawks feed their young animal prey and it shows on some of the cams.

Looking back, we have had quite a few posts about birds. Here are links to a few.
Build a Bird Nest (Human-sized)

Bird Watching and Making Nest Cards

Desert Bird Curriculum Guide

Pigeon Watching

Have fun and let us know what you see.