Author: Roberta (Page 508 of 561)

Weekend Science Fun: Loads of Lemons

This week the lemons are literally falling off the tree, so it is time for a round up of science experiments with lemons.

lemons

Lemon soda/pop
One of our favorite crazy chemistry projects is to try to reconstruct soda/pop flavors using ingredients found around the house and some fizzy water.

Gather:

  • Measuring spoons of various sizes
  • Hand juicer
  • Lemons
  • Limes
  • Oranges
  • Spices such as cinnamon, cloves, ginger, nutmeg
  • Unflavored carbonated water
  • Sweetener of choice
  • Small drinking cups or glasses
  • Slop bowl for dumping rejected recipes

If you supply a lemon soda to imitate, tape a piece of paper over the ingredients until the children have tried some recipes. Certain of the ingredients in citrus-flavored sodas were unexpected to us.

Or just allow them to create something that tastes good.

Have the children measure a standard amount of carbonated water into a glass and then add flavors. We’ve done this many times with many different friends and we’ve found that everyone enjoys it once they realize they are truly being given free rein to experiment.

Lemon batteries – a classic

Lighting up an LED with a few electrodes, wires and lemons is really exciting and it does work, although it is not easy.

Gather:
Lemons
Zinc electrodes (zinc coated nail works in a pinch)
Copper electrodes (or penny or copper wire)
Connection wires – with alligator clips is a plus
LED (available at hobby shops)

Hints:
1.    Use more than one lemon. Three or four hooked together works best, with two electrodes per fruit.
2.    Make sure you alternate electrodes, zinc/copper/zinc/copper. The zinc is negative, copper is positive.
3.    The LED also has a positive and negative orientation, so make sure it is in the circuit in the correct orientation. The slightly flattened side is the negative side.
4.    A trick I learned the hard way is to place the electrodes pretty close together. The figures often show the electrodes at opposite ends of the fruit, but moving them closer to each other works better.

This CSIRO site shows how to set up the lemon battery with the electrodes close together.

Lemon Juice as an Acid
Ever make a fizzy volcano or a film canister rocket with vinegar and baking soda? You can substitute lemon juice for the vinegar and still get similar results. If you add a squeeze of dish detergent with the lemon juice before adding the baking soda, it will froth even more.

Germinating Lemon Seeds
Save the seeds of the lemon when you make lemon juice. Wrap them in moist paper towel as described in the germination test post and keep them moist. In time, the seeds should sprout and you can grow small lemon trees. Lemons are susceptible to freezing, so only set them outside when temperatures are above freezing.

For the botanists:  Interestingly, many citrus can produce seeds without the flower being pollinated. Those seeds are identical to the parent, rather than being a mixture of traits.

lemons

We have talked about science with lemons before in previous posts:

When studying acids and bases, use lemon juice as a test substance. If you want to make a soft cheese, lemon juice can be used to curdle milk.

When you are finished, celebrate your science by making some lemonade, lemon cookies, lemon pie or lemon bread. Yum!

Let us know how your experiments turn out or if you have any great ideas for using lemons in science experiments.

Bug of the Week: Rose Aphids

Aphids are typically active only during the cool part of the spring season in Arizona, so now is when we see aphids.

Every wonder how aphids show up? After all, it looks like they don’t have wings.

rose aphids

These are rose aphids. Aren’t they a lovely pink color? By the way, the long tubes on their backs are called cornicles. Aphids emit chemicals from the cornicles. Some of the chemicals alert other aphids of danger (alarm pheromones) and/or actually deter enemies (defensive compounds).

The first aphids to arrive on your plants do have wings, like this one. They aren’t strong fliers and mostly they are carried in the wind.

rose aphids

The winged ones quickly have live babies.  Unlike most insects, these aphids do not lay eggs during this part of the life cycle.

I’ve circled the baby aphids in this photo.

rose aphids

I’m not worried about seeing these aphids. Even if I do nothing at all, they will disappear as the weather warms up.

For more information, try:

Cicadas and Aphids: What They Have in Common (Animals in Order Series) by Sara Swan Miller


Aphids (Blastoff! Readers: World of Insects) by Colleen Sexton


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Meet a Scientist Monday: Anna Botsford Comstock

Anna Botsford Comstock was a literal pioneer, born in a log cabin in western New York State in 1854. She was also a pioneer in many other ways. She was one of the first female students at Cornell University, starting in November of 1874. She was one of the first four women to be inducted by Sigma Xi, the Scientific Research Society founded in 1886. Eventually she became the first woman Professor at Cornell University, in Nature Studies.

Why did I choose Anna Botsford Comstock this week? Actually it is a personal story. I was introduced to Anna while I was a graduate student at Cornell University. The entomology building that I worked in was named after her and her husband, entomology professor John Henry Comstock. The fact her name was included on the building intrigued me and I wanted to find out more about her. Not many college campus buildings in that area are named after women. I later found out that a dorm at Hobart and William Smith Colleges is also named after her.

Anna had many talents. She was an artist. Early in her career she learned wood engraving and she illustrated many of her husband’s entomology textbooks. Her work was exhibited at the 1893 Exposition of U.S. Women Painters and is still cited by scientific illustrators today. She also was interested in literature and poetry, and wrote a novel that sold well. In addition to writing, and scientific illustration, she was an editor, a teacher and as well as arguably, a scientist. Her thesis for her Bachelor of Science degree was on “The Fine Anatomy of the Interior of the Larvae of Corydalus cornutus.” She eventually became part of the Nature Study Movement, and wrote and taught about natural history.

As I discovered more and more about Anna Botsford Comstock, I began to realize what a special person she was. She had a positive impact on many of the people who met her, and also on the generations that followed. For example, in her biography of Rachel Carson, author Linda Lear reveals Rachel Carson’s mother had read Anna Comstock’s nature writings. She then passed her interest to her daughter Rachel, who went on to write the highly influential book, Silent Spring.

Anna Botsford Comstock’s most monumental book, Handbook of Nature Study, was self-published in 1911 because no publisher was interested in a 938-page book on nature study. Ironically, the book no one would publish is still in press and still popular. It has gone through 24 editions and has been translated into 8 languages. Anna’s work led her to be called “the mother of the nature study movement” and to be inducted into the National Wildlife Federations’ Conservation Hall of Fame. Visit the Handbook of Nature Study Blog to see how people are still using and enjoying her work today.

Relevant Readings

Handbook of Nature Study by Anna Botsford Comstock

Trees At Leisure (1916) by Anna Botsford Comstock
This one of Anna’s personal favorites.

Rachel Carson: Witness for Nature by Linda Lear

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