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When I was young, other than teacher, I also wanted to be a plants biologist. My love for plants, compared to animals, is because plants do not run around. I have introduced my brave little cactus to you, and now I would like to introduce you to my mini garden.
The formal name of a mini garden is terrarium, which is an enclosed glass container, in which plants and small land animals are kept and observed. Mini garden is the more “romantic” name if you are only having plants inside the terrarium.
The mini garden is low maintenance. It is using the water cycle concept to keep the garden alive. It has its own self-sufficient ecosystem. The air, nutrients and water are recycled inside the container. The only outside energy that it needs is the light energy for photosynthesis.
Science Corner: Water Cycle
Though around 75% of the Earth is covered by water, that’s all the water we have. The water is going through water cycle again and again and again… so that the water is recycled and will not get lesser.
Water cycle is made up of 4 main processes:
1. Evaporation and transpiration
When the sun heats up the water in lakes, rivers and/or the ocean, the water turns into vapour and goes into the air (the sky).
In the mini garden, the plants transpire. That means the plants go through transpiration to get water vapour back into the air.
Condensation is the process of the water vapour in the air gets cold and changes back into liquid to form clouds.
The water vapour that you see on the glass container is the proof of condensation. When the water from plants transpiration touches the cold glass, it turns back into liquid.
When more and more water is accumulated, the clouds get heavy and water falls back to the Earth.
Similarly in the mini garden, the water vapour on the glass container is used for respiration and collection.
The water from the clouds (generally as rain) falls back in lakes, rivers and/or the ocean, some falls on land and is used by animals and plants. The cycle repeats again with evaporation and transpiration.
The water is collected at the bottom of the glass container in the mini garden. As long as the water cycle repeats, the plants have sufficient water to grow and thus you no need to water the plants frequently.
Thus, when you see the water vapour on the glass container, do not be alarmed, it is a sign of the water cycle keeps repeating itself.
Is there a link between Science and household chores? Yes, our mothers may not know the Science behind, but there certainly is a link.
- Drying clothes – With washing machine, the clothes are not dripping water after washed, but they are still damp. I especially like my clothes to dry under the Sun. Even without the Sun, we can still do some changes in hanging the clothes to let them dry faster.
- Thick clothes dry slower, so they should be put nearer to airy area or window. Reason: Airy area has more air flow and thus faster drying. Sunshine shines through window, thus clothes nearer to window will dry faster.
- Spread out the clothes as wide as possible to get a larger surface area.
- If you want to dry your clothes in minutes, iron them. The heat from the iron will dry them.
- Drying dishes – Same philosophy with large surface area, dishes should be put in a way that has large surface area to dry them. For cups and bowls, put them upside down so that the water will not be trapped inside them and make it slower to dry.
- Sweeping and mopping the floor – The reason why your mum ask you to off the fan when she is sweeping the floor is to avoid the dust being “fly” here and there. When mopping the floor, the fan is on to help to create an airy environment to dry the floor faster.
- Taking care of plants + watering – Plants need water, sunshine or light, air, soil and space to grow.
- Water the plants in early mornings or late evenings to avoid evaporation on a hot day.
- Put the plants outside or near the window to get as much free sunshine as possible.
- If your plant is not growing even though you have given it water, sunshine, air and soil, look at the flower pot. Is it too small for your plant? On the other hand, if you want a small plant, just give it a small pot, it will live (but not grow) happily.
- Keeping the air in the house fresh – Open the windows and doors to let the air flow. Air-conditioned rooms are usually stuffy, thus the windows and doors must be opened regularly so that there is air change and the rooms will be less stuffy.
The drying process is the evaporation process, in which the liquid phase (damp water) changes to gas phase (air) at temperatures below the boiling temperature at a given pressure. Evaporation usually occurs on the surface.
To increase evaporation rate:
- Increase the surrounding temperature
- Increase total surface area
- Increase air flow (wind / fan)
- Decrease the humidity of surrounding air
Science is not difficult to learn. If you are able to link it to daily life, you will remember the facts better. You may even have the interest to create something to facilitate your life.