Science Experiments on Environmental Education and Biology
Until the end of the 17th century, people believed that little animals like flies andworms could spontaneously be born from substances in decomposition or from mud. FrancescoRedi, Lazzaro Spallanzani and Louis Pasteur made experiments which proved the idea of thespontaneous generation was wrong. At your home or in your school you can made suchexperiments too.
1 - Take two glass jars with a screw top. Put in each a little piece of cooked apple and aspoon of vinegar. For a night, leave one of these jars opened so it can be visited byvinegar (fruit) flies. Close the other jar with the lid and sterilize it by placing it inboiling water in a pressure cooker for a half an hour. After removing it from the cooker,let it cool, leaving it closed. The morning after, let the possible bugs present into thefirst jar leave and then close it with a fine gauze or a plastic sheet on which you willmake some pinholes to allow oxygen to enter. After a few days, you should see some bugs inthe first jar, and none in the second one. What has happened in the first jar which hasnot happened in the second? Some vinegar flies laid eggs in the first jar and from themsome new flies are born. In the second jar, even if there had been eggs, these are deadbecause of high temperature in the pressure cooker. More eggs were not laid because thejar was kept closed. With experiments like this one, you can realize that living beingscannot born from nothing, but they are born from other organisms like them. Fall is themore suited season to do this experiment because vinegar flies are particularly active.
2 - Anyway you can try to adapt this experiment to organisms present at other times of theyear. For example, if you place some dry grass in a water glass, in few days a deal ofprotists will appear. If instead you will put the same material in a close glass pot andif you boil it, nothing will be born. Only some rare thermoresistant microorganisms,bacteria which resist the high temperature of boiling water.
... Uhm, and still there is something which is not working: if any living being comes fromanother living being, from where has come the first living being from which all others arederived? Can we consider completely falsified the theory of the spontaneous generationwith these experiments? Is it possible to assert that, even if the spontaneous generationis not the usual way with which living creatures are born, at least at one time duringbillions of years it has happened on the Earth or another place in the Universe? It is noaccident that there are scientists who study how life began in the first place.
Internet keywords: spontaneous generation.
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The Biology Standard Sensor Bundle includes a photosynthesis tank and the sensors required to perform 19 of the 24 Lab Activities in the Biology through Inquiry manual.
The soil is composed of many different sized particles. With this simple experiment you can separate the main components of the soil and evaluate their proportions.
1 - Go into a field an collect a sample of soil. Put it in a jar of water. Stir it well and let it settle. Observe and describe the different layers of materials.
2 - In water, particles settle more quickly the bigger they are. It is possible to use this property to determine the amount of each component of the soil. Put 3 parts water and 1 part of soil in the container (try 1 cup soil and three cups of water in a quart jar); shake the container for 5 minutes and let the material set. With reference to the figure 1, after 40 seconds measure the thickness of sediment. Call this A; after 30 minutes measure again and call this B; after 24 hours measure C. Now, by subtraction, you can determine the thickness of the main layers: C-B = layer of clay, B-A = layer of silt, A = layer of gravel and sand. Using a sieve with 2 mm holes (less than 1/8 inches), you can separate the gravel from the sand and determine their ratio. On the basis of these data, calculate the content (%) of each component of the soil sample.
3 - Repeat the same experiment with soil collected in other places or that have a different geological origin (i.e: meadow, wood, river bank) or anyplace the soil has a different consistency or texture (i.e: muddy, sandy). Describe the composition of each soil and try to explain the differences. You can also apply this technique to evaluate the composition of the soil for a potted plant, and correct it. Example: if water doesn't drain well, would more sand help? If it needs to hold water longer would clay or organic matter be helpful?
4 - With a microscope, measure the size of the particles. With a clock, measure the time to drop to the bottom of a jar of water. time of the particles in water as a verses their size. Then graph with the Y-axis for the size of the particle and X-axis the time to fall.
Soil and Environment Activities
Soil description and classification
Internet keywords: soil sedimentation test.
4879 best Elementary Science Activities & Lessons …
Repeat this Experiment:
In another experiment, Ingenhousz, placed a small green aquatic plant in a transparent container of water and exposed the container to bright sunlight.
2013 Public Display - Canada Wide Virtual Science Fair
In its simpler form, this experiment is particularly suited to elementary schools.
1 - Put some beans in a little jar containing some moist cotton wool. Keep the jar closedto maintain the humidity. Every day pull out the cotton and observe the state of the seedsand measure the length of their roots.
2 - Students in junior high schools or high schools can try to evaluate the influence ofparameters such as temperature, light and nutrients on the speed of germination of theseeds. If seeds are placed in gelatin, it is possible to observe the germination withoutextracting them from the jar.
3 - You can also collect seeds of different plants and determine their vitality (percentof seeds which germinate) as a function of time to harvest.
Exploring Seed Germination
Germinating Seeds on Gelatin
The Great Seed Mystery For Kids
The Wonderful World of Seeds
Internet keywords: germination seeds student.
Plant Experiments, Creating Oxygen - Kids Science
Joseph Priestley carried out an experiment that showed that plants produce oxygen. He put a mint plant in a closed container with a burning candle. The candle flame used up the oxygen and went out. After 27 days, Priestley was able to re-light the candle. This showed that plants produce a gas that allows fuels to burn. This gas is oxygen.