Thursday, February 26, 2009

More Hydroponics-Starting to Harvest

We had some lettuce on our sandwiches today. The tomatoes are getting bigger, but nowhere near flowering or fruiting. Here's an update on our indoor water-based gardens:

1. The original containers and the paper cups we were using to hold the seedlings became moldy. We moved the plants back into the plastic cages and changed the containers.

2. We have been testing the pH of the water regularly. After our visit to a local hydrofarm (to be described soon), we've been trying to keep it to 5 or 6. We have been adding vinegar or aspirin to bring it down. This seems to be working.

3. Both lettuce and tomatoes continue to grow rapidly. However, they are kind of floppy.A look at the nutrient mixture we are using (Formula X) found no calcium among the listed ingredients.

Important Nutrients

Plants need about 16 different essential elements for optimum growth. Macronutrients, which are ordinarily found in soil, are needed by plants in rather large amounts. (Hydrogen, oxygen, and carbon are also necessary in large amounts, but are available to plants from the air and water.) The following are essential macronutrients:

  • nitrogen (N)–Promotes development of leaves
  • phosphorus (P)–Aids in growth of roots
  • potassium (K)–Helps plant resist disease
  • calcium (Ca)–Helps promote new root and shoot growth
  • magnesium (Mg)–Contributes to leaf color and helps absorb sunlight
  • sulfur (S)–Contributes leaf color
We called the company and was told that "not everything is listed." But given how weak the plants are, we are going to look for a calcium supplement to add. Calcium nitrate -- saltpeter, which I didn't manage to find when doing chemistry last year! -- seems to be what we need. We'll have to try the hydroponics shop again...

Monday, February 23, 2009

Planning Biology Labs

In the coming weeks I am hoping to do more regular biology labs in conjunction with some of the topics I would like to cover, including cells, biological processes, and anatomy. In preparation, I'm looking at some of the books I already own and teaching plans and activities online. I'll be adding to the list of Biology Education Links in the sidebar and mentioning sites that look interesting as I come upon them. And of course as we do them we post step-by-step descriptions of labs here as well.

Here are some of the new resources I've found so far:

The Biology Project is an interactive online resource for learning biology developed at The University of Arizona. The Biology Project is fun, richly illustrated, and tested on 1000s of students. It has been designed for biology students at the college level, but is useful for high school students, medical students, physicians, science writers, and all types of interested people.

CELLS alive! represents 30 years of capturing film and computer-enhanced images of living cells and organisms for education and medical research. The site has been available continuously and updated annually since May of 1994 and now hosts over 4 million visitors a year. All text, images, and layout are provided by me, Jim Sullivan.

BioWeb exists to aid teachers of Biology in New Zealand schools. All activities can simply be down loaded and used in the classroom and include general strategies which can be adapted to many topics and links to further resources at the end of each section.

The Structures of Life, an online school publication from the National Institute of General Medical Sciences.

Hands-on Activities for Teaching Biology to High School or Middle School Students: Ingrid Waldron and Jennifer Doherty from the Biology Department at the University of Pennsylvania have developed hands-on, minds-on biology activities for grades 6-12 in collaboration with colleagues at Penn and K-12 teachers.

NYS Living Environment Regents Exam Prep from Oswego City School District

Online Resources to go with Glencoe's text Biology: The Dynamics of Life 2004, including practice tests, links to virtual dissections, etc.

Monday, February 16, 2009

Bird Feeder Myths

We've never put out a bird feeder (although we had some that were given as gifts). At out last house the squirrels were too fierce. At our present house we do get the occasional stray cat in the yard, but that's about it. Maybe we'll try a hummingbird feeder this spring.

In the meantime, here's a list of bird feeder myths that I had always taken at face value. It comes from the Great Backyard Bird Count website:
Myth: If birds eat uncooked rice, it can swell up in their throats or stomachs and kill them.

Fact: Plenty of birds eat uncooked rice in the wild. Bobolinks, sometimes called "rice birds," are a good example. While rice is okay for birds, many wedding parties now throw bird seed instead.
Myth: Birds can choke on peanut butter.

Fact: There is no documented evidence for this. However, mixing peanut butter with grit or cornmeal will break up the stickiness if you are concerned.

Myth: Birds become dependent on bird feeders.

Fact: Birds become accustomed to a reliable food source and will visit daily. However, birds search for food in many places, so if your feeder goes empty, most birds will find food elsewhere. During periods of extreme ice, snow, or cold, the sudden disappearance of food might be a hardship; if you are leaving town during freezing weather, consider having someone fill your feeder while you're away.

Myth: Birds’ feet can stick to metal perches.

Fact: This is not likely. A bird's legs and feet are made up mostly of tough tendons that have little blood flow during cold weather. However, we've heard rumors of feet sticking to perches: if you observe this unfortunate circumstance, please take a picture and send it to Project FeederWatch.
Myth: Feeding hummingbirds in late summer can stop their migration.

Fact: Some people believe they should stop feeding hummingbirds right after Labor Day because the birds' southward migrations will be interrupted. However, a bird's migratory urge is primarily triggered by day length (photoperiod), and even a hearty appetite won't make a bird resist that urge. In fact, your feeder might provide a needed energy boost along a bird's migration route.

Sunday, February 15, 2009

Our Great Backyard Bird Count

As I mentioned on GeekDad, this weekend is the Great Backyard Bird Count. Because they ask for positive identification of the birds you report, we brought out cameras so we could verify our sightings. Which were not all that impressive. We saw but did not photograph a woodpecker and a few small birds which were too far to ID. Near the outlet of the Fish Creek into the Hudson River we saw a flock of mallards. And after a walk up and back along the canal, we came across this specimen. I don't think it's native to this area, and not usually seen this time of year. But in the interest of completeness, we'll report it!

Friday, February 13, 2009

Devolve Yourself

As Darwin Week draws to a close, here's a little evolution fun. The Open University website has a tool that lets you devolve yourself back to your primitive ancestors. Here's what one of my kids looks like millions of years in the past.

The British-based online university also has more Darwin information put together in conjunction with the BBC. If you're in Britain you can even order a free Tree of Life poster.


Monday, February 9, 2009

Darwin Week at GeekDad

It's Darwin Week at GeekDad, the blog for which I am privileged to be the token mom. When I suggested the theme week I hoped to contribute a few posts about my family's exploration of opposition to teaching evolution. However, the final consensus was to leave out any mention of creationism/intelligent design. Of course, the commenters have brought it into the discussion anyway. Unlike last year's post on the topic, the comments to the post I contributed this year have at least been coherent. But it's still upsetting that people want to "let kids decide what to believe." Here's my reply to that suggestion:
We should teach evolution to our kids because:
1) It is the basis of all modern biology;
2) It provides the best explanation of how living things came to exist in their present form;
3)It fits the observations of thousands of scientists working over hundreds of years (Darwin used earlier discoveries to formulate his theory);
4) It makes predictions which have been verified (for example, that transitional -- "missing link" -- fossils will be found between one species and another);
5) Like the laws of physics and facts about the Earth's place in the Solar System, it is somewhat counterintuitive -- meaning it is not something kids will necessarily figure out on their own from direct observation;
6) After a certain age it is difficult to correct inaccurate ideas about the world. (Go to the article Unlearning Bad Science by John Merrow to read about the study which asked graduating Harvard seniors why it's warmer in summer. Nearly all said it's because the Earth is closer to the sun!)
7) We want our children to have accurate information about how the world works, so that they can make good decisions about how to run it when it's their turn.

Monday, February 2, 2009

Hydroponics Update

What happened to the first crop:
For our project this month, we've been growing more hydroponics plant (lettuce and cherry tomatoes this time.) Unfortunately, after the second day growing them, all the plants grew moldy, and we had to throw them out and start over.
Starting over:
We've been growing them in plastic cups now, and we use cocoa fiber soil. The new ones haven't grown any noticeable mold, and have been growing pretty nicely. We have noticed that the tomatoes aren't growing as fast as the lettuce, though.

Improving our set-up:
On day 18, we moved the lights closer to the plants, so they would absorb more light. Also, we moved the shelf closer to the heating vent.

Moving to bigger quarters:
We also recently moved the tomato plants into some empty milk cartons we cut holes in, and they've been growing at a faster rate now. They should be ready to harvest in about a week. So, the project has been going pretty well so far.
Saratoga Organics, a local hydroponics store, where we bought some of our supplies.

Sunday, February 1, 2009

PBS Evolution series

We have had great success this school year using documentaries (and some fictional movies) to learn about history. And despite the number of print resources I've found on evolution, I'm having trouble finding a way to go over this material together with the kids. So I did a quick search for a document series and came up with the 8-part DVD set from PBS. I've got it on reserve at the library, so after we watch it I'll put a quickie review on the link at my Amazon store. But from the reviews I've already read, it looks perfect for our purposes.

In the meantime, there's a companion website at PBS with web activities, video clips and more.