聽聞星期六、日，迫爆郊野公園，林家係屋企坐了兩日。今日出動了，去了西貢吹吹海風⋯⋯不算是太多人，但仍然有人行街街。在西貢食個午餐，玩下scooter就走了⋯⋯
Monday, 2 March 2020
Sunday, 1 March 2020
At Home Science Experiments: Walking Water
又再玩多個小實驗，但有點失敗，哈哈！！時間太長，因為中間個杯的水太多，個流程太慢。廚房紙巾應該先濕水，可能會快些。最後，就是吱吱和嘩嘩的手勢不同，應該一個落得多咗色素，所以中間個杯不是「紫色」。噢⋯⋯
The water moves up the paper towels through a process called capillary action. The paper towel is made from fibers and the water is able to travel through the gaps in the fibers. The gaps in the paper towel act like capillary tubes and pull the water upward. This is what helps water climb from a plant’s roots to the leaves at the top of the plant or tree.
The water is able to move upward against gravity because of the attractive forces between the water and the fibers in the paper towel.
At Home Science Experiments: Color-Changing Milk
What You'll Need:
- Milk (whole or 2%)
- Dinner plate
- Food coloring (red, yellow, green, blue)
- Dishwashing soap (Dawn brand works well)
- Cotton swabs
What To Do:
- Pour enough milk in the dinner plate to completely cover the bottom to the depth of about 1/4". Allow the milk to settle.
- Add one drop of each of the four colors of food coloring — red, yellow, blue, and green — to the milk. Keep the drops close together in the center of the plate of milk.
- Find a clean cotton swab for the next part of the experiment. Predict what will happen when you touch the tip of the cotton swab to the center of the milk. It's important not to stir the mix. Just touch it with the tip of the cotton swab. Go ahead and try it. Did anything happen?
- Now place a drop of liquid dish soap on the other end of the cotton swab. Place the soapy end of the cotton swab back in the middle of the milk and hold it there for 10 to 15 seconds. Look at that burst of color! It's like the 4th of July in a bowl of milk!
- Add another drop of soap to the tip of the cotton swab and try it again. Experiment with placing the cotton swab at different places in the milk. Notice that the colors in the milk continue to move even when the cotton swab is removed. What makes the food coloring in the milk move?
What's Happening:
Milk is mostly water, but it also contains vitamins, minerals, proteins, and tiny droplets of fat suspended in solution. Fats and proteins are sensitive to changes in the surrounding solution (the milk). The secret of the bursting colors is the chemistry of that tiny drop of soap. Dish soap, because of its bipolar characteristics (nonpolar on one end and polar on the other), weakens the chemical bonds that hold the proteins and fats in solution. The soap's polar, or hydrophilic (water-loving), end dissolves in water, and its hydrophobic (water-fearing) end attaches to a fat globule in the milk. This is when the fun begins.
The molecules of fat bend, roll, twist, and contort in all directions as the soap molecules race around to join up with the fat molecules. During all of this fat molecule gymnastics, the food coloring molecules are bumped and shoved everywhere, providing an easy way to observe all the invisible activity. As the soap becomes evenly mixed with the milk, the action slows down and eventually stops.
Try adding another drop of soap to see if there's any more movement. If so, you discovered there are still more fat molecules that haven't found a partner at the big color dance. Add another drop of soap to start the process again.
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