Industrial societies manufacture huge quantities of goods. Once used, these products arecast away. Hence, on one hand we substract great amounts of resources from nature, on theother hand we make enormous heaps of garbage which pollute the environment. If you thinkof it, a lot of materials which are discarded could be reused. In fact, metals, plasticand glass can be used in manufacturing new items. Paper and fabric can be turned back intopulp and fibers, and reassembled into new products. Organic wastes of kitchen, usuallymade of vegetable and animal substances, and garden material, can be composted and used asfertilizer. Wood can be burned, yielding electrical energy, heat and carbon dioxide whichwill be used by other plants to produce more wood. Recycling of waste materials has thedouble advantage of reducing the need for raw materials, and the amount of rubbish.
Every day for a month, separate the different kinds of scrap of your home, weight them andwrite out a list. At the end, estimate the amount of materials which can be recycled,evaluate the recycling and waste management program of your community. Highlight theproblem areas of the system. Assess the problems created by not easily recyclable things,and by the polluting ones: paint cans, batteries, oils, detergents, medicines, etc. Bringout the difficulties and the questions facing particular problems in the recovery ofwastes. Ask the authorities of your city. Write a guide for families on how treat wastesin the right manner. Show this guide and the report of your research to your teacher.
Environmental Defense, Recycling
Recycling - At School
Recycling Obscure Materials
Global Recycling Network
The Internet Consumer Recycling Guide
Internet keywords: recycling.
Drosophila, best known as vinegar fly or fruit fly, is the little fly you see flyingaround vinegar and on fruit during the fall. Why raise vinegar flies? To observe theirdevelopment, to observe the chromosomes of their salivary glands during division, toperform experiments on genetics, finally as food for amphibians that have just completedtheir metamorphosis. In this case it is necessary to breed a species that can't fly. Youcan obtain individuals with vestigial wings (wings which are not fully developed)at a university Biology or natural sciences department.
Culture medium recipe for drosophila: water 83 ml, agar-agar 0.8 g, sugar 5 g, brewer'syeast 10 g, alcohol 1.3 ml, nipagin
0.25 g. Nipagin M is used as a preservative in foods and cosmetics, like agar-agar, youcan buy it at the stores that sell science items for laboratories. Mix the yeast and thesugar, add agar-agar and water and simmer for 3 minutes. Turn off the heat. Dissolve thenipagin in alcohol and add to the rest when it has stopped smoking. Mix and let it set.
You can find other recipes at the following websites:
Aquick and simple introduction to Drosophila melanogaster
Fruit Flies - Drosophila melanogaster
Drosophila Culture (how to culture flightless fruit flies)
Observing the Development of Drosophila in Apple Juice Agar
Drosophila Genetics Lab I
A bibliography for an insect field biology course
La drosophile (in French)
Internet keywords: drosophila culture -cells, wingless fruit flies vinegar fly.
Spermatogonia are actually the outer layer of small cells. The large cells labeled spermatogonia are actually primary spermatocytes, and the smaller cells are secondary spermatocytes.
Making an aquarium or a terrarium is not a complicated thing. Learning to build them isvery useful for those who are fond of breeding animals, observing them, taking picturesand movies. You can use an aquarium to breed fish, amphibians, protists, algae, artemia,shrimps, etc. You can use a terrarium to breed many species of animals, but avoid raisingspecies which suffer in captivity. Aquaria and terrariums can be used also to take picturesof animals temporarily taken from their environment.
In their simpler form, acquaria and terrariums are simple glass boxes enclosed on 5 sidesand which can be provided with a lid. This simple container is suitable to breedamphibians and as a terrarium. Aquaria for fish require a compartment for a filter, a pumpfor water circulation, another pump for air, a thermostat, lighting, etc. We'll deal ofthe simplest aquaria.
How you can build an aquarium? In first you have to make a drawing. The bottom glass hasto be surrounded by the other four walls and it has to be the thickest. The thickness ofthe plates has to be proportioned to the size of the aquarium. Avoid building too wide,and more importantly, too high an aquarium. The pressure of the water increases and couldunglue the plates. After having drawn the acquarium you have to cut the glass plates bymeans of a glasscutter. To do this keep the glasscutter vertical and push down with forcewhile you move it along a ruler. This operation require practice, so use some scrap piecesuntil you have the necessary manual ability. It is important you use a sharp glasscutter,kept in oil to avoid rust. Before gluing the slabs, you have to round off the edges withsandpaper in order to remove their sharp edges. With some acetone, clean the slabs wherethe silicone rubber will be deposited. As the acetone is toxic, work outdoor or in a wellventilate piece. Use high quality transparent silicone. To keep the internal walls free ofexcessive glue, on the slabs and near the gluing positions, place stripes of sticking tape(figure 6). When the silicone is cured, remove these stripes and the excess glue.
: handling and cutting glass is a dangerousoperation which has to be made only by adult people wearing gloves and a heavy apron. Away to elegantly solve this problem is to order plates. A hardware or building supplystore can help. Never move aquaria and terrariums containing water or stones, move them onlywhen they are empty. Do not place aquaria in positions where a water leak could damagesomething below them, for example over electrical devices or sockets, and books. Onlyadults should handle glass-made aquaria or terrariums. Give children transparent plastictanks. Do not keep dangerous or rare organisms. Do not breed and most important, do notfree species which do not belong to your environment! Do not free sick animals or plants.
Reef Aquarium Guide
CyberAqua (list of links)
Internet keywords: aquarium glass homemade.