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Category: Biology (Page 35 of 40)

Weekend Science Fun: Taste and Tongues

January 18, 2010 / / 0 Comments

This weekend we were inspired by the book Animal Tongues by Dawn Cusick to do some some science experiments with our tongue and sense of taste.

1. Dry Tongues and Taste

Gather:

  • a paper towel
  • some sugar

Normally your mouth is wet because of saliva. Let’s see if the wetness has any impact on taste. Use the paper towel to dry your tongue. Once dry, keep your tongue sticking out. Pour a small amount of sugar on your tongue. Can you taste the sweetness? Bring your tongue into your mouth and allow the saliva to wet the sugar. How does it taste now?

Go ahead and try some other household items, like salt, saltine crackers, etc. What about wet items?

2. Smell versus Taste

Gather:

  • blindfold
  • two flavors of ice cream, (or other type of food that tastes different, but has the same texture)
  • spoons
  • fresh cut lemon wedges

Ask volunteers to wear the blindfold. Hold the lemon under their nose. With the lemon still under their nose, ask them to taste samples of the two different flavors of ice cream. Can they tell the flavors accurately?

Expansion:  try to tell different foods apart with a blindfold on, while holding your nose.

 

If you think these activities are fun, try a few of the experiments at Neuroscience for Kids

I will be reviewing the book that inspired these experiments at my Wrapped In Foil blog.

honeybee tongue

Honey bees have complex tongues.

Weekend Science Fun: Winter Botany

January 9, 2010 / / 4 Comments

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 sidebar 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 within the green bean fruit and show an example. It also is on the Teacher’s side.

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!

Mosses, Ferns, Liverworts and Horsetails: Science Activities

November 15, 2009 / / 2 Comments

Today let’s take a look at some plants that are often ignored because they lack big, showy flowers. Ferns, liverworts, horsetails and mosses do not produce seeds, but produce spores instead.

Activity 1. Identification

Go on a nature walk and see if you can spot any of these spore-producing plants. Record where you see them and what the surrounding environment is like.

Mosses are low-growing plants with tiny leaflets. They coat the ground like velvet.

Ferns have leaf blades divided into many parts.

Photo from Flickr

Liverworts have rounded leaflets that are said to resemble the liver.

Horsetails have tall stems, with segments. Their leaves are long and fine, resembling a horse’s tail.

Did you find any of these plants?

Activity 2. Searching for spores.

Because these plants make spores instead of seeds, it is fun to see if you can find the structure that produces spores, the sporangium. If you don’t have any of these plants growing nearby, check with your local florist. They sometimes use ferns in bouquets.

See the dark dots on the underside of the frond? Those are the sporangia.

Check out this video of fern spore capsules shooting out the spores like a catapult!

The yellow brown structures on this moss are the sporangia.

What is the difference between a seed and a spore? A spore is a single cell, so it is tiny. In comparison, a seed contains many cells making up the embryo of the plant, the food that is stored with it, and a cover or coat.

Activity 3. Moss, horsetail, fern and liverwort habitats.

When you went on the nature walk, where did you find these plants? Did you find them mostly in wetter areas? Were any growing in the forest?

Did you find them growing together?

Ferns, mosses, horsetails and liverworts have somewhat similar growing requirements. Liverworts and mosses are considered to be non-vascular plants because they lack the special water-carrying tubes found in other plants. They must stay in relatively wet environments and can’t grow tall.

Aren’t these interesting plants?

Edit: If you are interested in learning more, take a look at Steve Parker’s Ferns, Mosses and Other Spore-producing Plants book, which is part of the Kingdom Classification series. I have a review at WrappedinFoil.

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