Hands-On Life Science

I have used these experiments and demonstrations with elementary school kids--mostly K through 6th grades.

Daphnia Toxicology

Reference:
"Toxicology for Middle School: The Effects of Common Substances on Daphnia", R. N. Russo and S. Parrish, J. Chem. Ed., 72, pp. 49-50, (Jan. 1995).
"A Brine Shrimp Bioassay for Measuring Toxicity and Remediation of Chemicals", Marya Lieberman, J. Chem. Ed., 76, pp. 1689-1691, (Dec. 1999).

Daphnia are small crustaceans commonly found in pond water.
They are fascinating to watch under a microscope. Caffeine caused their heartbeat to increase noticeably, and alcohol depressed it.
You can use Daphnia to test for the toxicity of common substances such as alcohol, tobacco, coffee, and over-the-counter drugs.
Our Daphnia were somewhat finicky creatures. I had to use them as soon as possible after arrival--no later than 24 hours.
See the article for full details.
Be prepared for surprises: we found tobacco to be exceptionally toxic, and alcohol (or at least red wine) definitely prolonged the lifespan of our Daphnia!

If you are doing these experiments at a school, make sure you get permission to bring alcohol, tobacco, and over-the-counter drugs on campus!

Seeds

• Trees
  • maple ("helicopter")
  • acorn
  • walnut
  • pinecone
• Fruits & Vegetables
  • apple
  • orange
  • watermelon
  • peach
  • cherry
  • grapes
  • pumpkin
  • corn
  • beans
• Other Foods
  • sesame seeds
  • poppy seeds
  • caraway seeds
  • sunflower seeds
• Flowers & Weeds
  • marigold
  • zinnia
  • nasturtium
  • dandelion
  • burrs

Maple seeds and beans are good to dissect.
Try sprouting beans in paper towels in a glass jar.
How do seeds disperse? (Wind; stick to fur and clothes; hidden by squirrels; excreted by birds)
How are seeds protected? (Hard shells, waxy coverings)

Taste & Smell

Taste

Equipment and Materials:

• salt water (salty)
• sugar in water (sweet)
• vinegar (sour)
• caffeine dissolved in water (strong tea did not work well)
• small disposable cups
• Q-Tips

Procedure:
Use a Q-Tip to put a small amount of each liquid (one at a time) on your tongue.
Are some areas of your tongue more sensitive to different tastes?

Smell

Equipment and Materials:
Prepare 20 small vials: in each vial put one of the following substances on a cotton ball or a small piece of filter paper.
Identify each vial with a number.