 |
Group Activities |
| The presence of water in food. | Water is the element that is present in the highest quantity in all living creatures. Try and make a table in which you show the different percentages of water in all the foods you usually eat (fruit, vegetables, meat and fish etc.) |
| Pollution in water! | Can you estimate the presence of sources of non-visible pollution in water, observing living organisms in it? Brown alge and blue alge are symptoms of pollution because they develop near effluent. On the other hand, river crayfish, trout and pike are a sign of good-quality fresh water. |
| Damage caused by coastal erosion (or by the rising sea-level). | Try to reconstruct the changes in a stretch of coastline you know, from 50 years ago to the present day. What has changed? Why? What has happened to metres and metres of land? What will all this lead to? |
| Find out how the water in the soil pollutes plants. | We all know that plants take their food from the water present in the soil and the substances that are dissolved in it. This often has serious consequences (in the case of chemical substances which damage the health of plants). You can test this phenomenon by dissolving a dye in a flowerpot of soil, and observing the small plants that live in that soil. They will take on the colour you have introduced (the result of experiment is even clearer if you use a white flower instead of a green plant). |
| Water is life for plants! | Water is the primary source of life for plants. Let's observe how a potato needs only a pot full of water in order to grow and make leaves (soil and compost aren't necessary). It's very easy and the effect is really original! |
 |
Projects |
| Water habitats |
The best way to observe a freshwater habitat is to make your own! Why don't you: 1. Make an aquarium. To make the aquarium, you will need a glass or plastic tank, gravel, water plants, water animals, some rocks and dead wood, and pond water or rainwater. 2. Make a rocky seashore aquarium. You will need rocks, shell sand, seawater, shore animals such as anemones, crabs, prawn (make sure that you are not putting protected species in your aquarium!), a tank and a filter unit (available at pet shops). 3. Make freshwater from salty water. Take a bucket and put some salty water in it. Place a beaker in the middle of the bucket (you may have to weigh it down with some stones). Cover the bucket with a clean sheet of plastic. Place a weight in the middle of the sheet so it sags forming a cone leading into the beaker but not touching it. Place the bucket in the sun. Water will evaporate into the beaker, leaving the salt behind. 4. Make a pond in your garden. In order to closely observe the life of acquatic creatures and their ecosystem, the best thing to do is to make a pond in your garden. Here's how to do it: a. In an area of your garden that isn't covered by tree branches, dig a ditch with sloping sides, with a surface area of at least 2 square metres and a depth of 60 cm. b. Then level the bottom and sides well and scatter a layer of sand over them. c. Put a strong plastic sheet over the whole hollow, make it adhere to the walls well, and make sure that it overlaps the edges by at least 30 cm. d. The edges of the plastic sheet should be completely covered with rocks, stones or bricks. e. Lastly, fill the hollow with water (preferably rainwater), making sure you don't form kinks in the plastic sheet (possible traps for fish). |
| How to make a "solar still" | A solar still can make enough water to meet a person's needs, in 24 hours. Here's how to make it: a. Dig a cone-shaped hole of one metre diameter, half a metre deep. b. On the bottom place a bucket connected to the outside by a small rubber or plastic pipe, and cover everything with a sheet of heavy transparent plastic, because in this way the drops of water adhere better. Two square metres is the best size of sheet. c. Once the sheet is in place, you need to buttress the surrounding edge with soil and rocks in order to trap in the humidity. d. Put a stone or a heap of soil in the middle of the plastic sheet. The humidity of the soil will evaporate and condense under the sheet because of the heat of the sun, forming in this way lots of droplets that will end up in the bucket. We can collect about one and a half litres of water per day using this system. |
| Try treating water: there are a number of different ways to do it! | We all know that often the water present in nature is not drinking water, and needs to be treated first. There are a number of ways to distil and purify water. Here are the simplest ways that you can put into action yourself: 1. Settling: Leave the water in a container overnight. In this way the solid particles will separate from the molecules of water. This first method is usually used before the others. 2. Filtering: There are various different types of porous filters (made of paper, fabric or other materials). You can also make your own by putting a number of layers of gravel, charcoal and sand, one after the other, into a container pierced with holes. The water will pass through these layers. 3. Boiling: Boil the water for 10-15 minutes and it will be freed of all the bacteria contained in it. But water obtained in this way may appear heavy and insipid. So we recommend that you pour it from one container to another several times, and add a pinch of bicarbonate of soda. |
