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Weekend Science Fun: Germination test

March 1, 2009 / / 0 Comments

Last week we looked at planning a children’s garden. Now are you ready to do some gardening-related science activities? The germination test project this week is both useful and educational.

Ever have a pile of leftover seed packets tucked away in a cupboard somewhere? You know, the ones with the “Packed for 2001” stamped on them?

seeds packets

If you are not sure whether the seed is still viable or whether planting it would be a waste of time, there’s an easy test to find out. It’s called a germination test.

Pull out your old seed packets. Note: check the packages carefully to see if the seeds are treated with pesticides, such as fungicides or insecticides. Avoid handling pesticide-treated seeds.

For each packet you and/or your children want to test, gather the following:

  • Paper towels
  • Either paper plates and plastic wrap /or zip-loc style plastic bags
  • Water

Wash your hands prior to starting and try to keep everything as clean as possible.

1. Prepare a separate damp paper towel for each different seed packet.

2. Select 10 seeds from each packet you want to test. For example, you might have 10 marigold seeds and 10 corn seeds.

3. Lay the 10 marigold seeds on a damp paper towel and fold it over. Then either lay the towel on a paper plate and cover with plastic wrap, or slip the damp paper towel into a zip-loc bag. Repeat for the 10 corn seeds or whatever kinds of seeds are in the rest of the packets.

germination test

3. Come back in 24 hours and 48 hours and look for the tiny root (radicle) poking out of the seed, a sign that it is germinating.  Count how many seeds germinate and how many do not. Certain seeds, like carrots, take a long time to germinate (up to 2 weeks), so keep them moist and don’t give up on them right away. If no seeds germinate after two weeks, then perhaps it is time to invest in a new batch of seeds.

You can calculate the percent germination by dividing the number that germinated by the number you set up. For example if 9 seeds germinated out of 10, then your percent germination = 90%. If only 5 germinated out of 10, then the percent germination is 50%.

If the seeds germinate, transfer the tiny sprouts to containers filled with moist soil and you’ll have transplants ready when it is time to start your garden.

Tie-in books for the youngest set (Affiliate cover links go to Amazon):

A Seed Is Sleepy by Dianna Hutts Aston and illustrated by Sylvia Long

How a Seed Grows (Let’s-Read-and-Find-Out Science 1) by Helene J. Jordan (Author), Loretta Krupinski (Illustrator)

From Seed to Plant by Gail Gibbons

Gail Gibbons has definitely been one of our favorite nonfiction authors and this book does not disappoint.

And books for adults:
Seed to Seed: Seed Saving and Growing Techniques for Vegetable Gardeners by Suzanne Ashworth Kent Whealy

Bug of the Week: Crane Flies

February 25, 2009 / / 10 Comments

With all the rain this winter we’ve had an emergence of large insects that look somewhat like a giant mosquitoes or what my neighbors called “long-legged wasps.” Here is what they are seeing (the thumb is for scale).

crane fly

They have nothing to be concerned about. This big, fragile fly is called a crane fly.

Crane fly adults are often over an inch long with two flimsy wings that they hold straight out from their sides when at rest. Although their appearance is unusual, crane flies are truly gentle giants of the insect world. They don’t bite or sting. In fact, they do not even feed as adults. Their only interest is finding other crane flies.

The photo of the adult was from a few years ago. This afternoon my son found the larva while digging in some soil.

crane fly larva

The larval stages of crane flies are sometimes called leatherjackets because of the leathery-looking covering over their bodies. I was able to capture the end of its abdomen as it crawled away, so you can see the tubes it breathes with when it is under water. You can see the outline best in the shadow behind it.

The larvae munch on dead leaves piled up in wet areas, part of nature’s clean up crew. With all the rain storms we’ve had lately, the crane flies have had a lot to eat and so we have a lot of them.

crane fly larva

Interestingly, the larva emitted a brownish substance from the tip of its abdomen as it crawled away, almost like the “chewing tobacco” that grasshoppers make from their mouths if you pick them. I’ve never read anything about crane fly larvae having chemical defenses, but that’s what it looked like.

I’m afraid this larva was moving too fast for a good photo. For better views, you might want to check these truly spectacular photos of crane flies.

Meet a Scientist?

February 23, 2009 / / 1 Comment

What do you think of when you hear the word “scientist?” The classic visual of a person in a white lab coat peering into a glass tube filled with colorful liquid? Someone tucked in a laboratory somewhere, far from the real world?

Actually, nothing could be further from the truth. I think it would be helpful for children to choose a career in science if they knew what scientists really do and what they really are like. To help children learn more about scientists I’m considering having a “Meet a Scientist Monday” as a regular post. Let me know if you like the idea and even better, if you know of a scientist who would be willing to let me interview him or her.

Here’s an example of a scientist, using information from Dr. Thomas Eisner’s book, “For Love of Insects” and from his website (go visit it just to see his photographs and his FanciFul Designs).

1. What is Dr. Eisner’s scientific field?

Dr. Eisner is a chemical ecologist. That means he studies how insects and other arthropods communicate and defend themselves using chemicals.

2. Does he spend all his time in a laboratory?

No, Dr. Eisner does much of his work outside in natural areas. In fact, he calls himself a field biologist. Dr. Eisner is also a nature photographer, as you can see from his website.

3. Did he always want to be a chemical ecologist?

Dr. Eisner always liked insects, and his father was a chemist, but he didn’t become a chemical ecologist until after he got his PhD degree. He says he had the idea in his mind that he would like to study chemicals and insects, but it wasn’t until he found a special beetle called a bombardier beetle that he was actually able to do it.

4. Where does he work?

Dr. Eisner is a Professor at Cornell University.

5. Why do you call him Dr. Eisner? Is he a medical doctor?

Many scientists go to graduate school for a a degree called a doctorate of philosophy or PhD for short. Anyone who gets a doctorate is called Dr.

6. Does he wear a laboratory coat?

I met him when I went to school at Cornell and he just wore regular clothes.

Do you have any other questions about Dr. Eisner? If so, let me know.

Here is information on two books by Dr. Eisner written for interested adults:

For Love of Insects by Thomas Eisner

Secret Weapons: Defenses of Insects, Spiders, Scorpions, and Other Many-Legged Creatures
by Thomas Eisner, Maria Eisner, and Melody Siegler

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