Jiaxing Senior High School BC Offshore Program
What factors can affect the activity of yeast? This question has become the topic for Grade 11 students to study during the winter holiday. Under the lead of the chemistry teacher, Mr. C, the students actively completed this experiment and handed in the lab report during the holiday.
Yeast is a kind of single cell fungus that can ferment sugar. It can be used in brewing and pathogenic bacteria. Therefore, it has wide uses in our lives, such as the baking of cake and the brewing of wine. After understanding the characteristics of yeast, we started the experiment based on the principle that yeast can ferment sugar into alcohol and carbon dioxide. The experiment uses the control variable method to determine whether the amount of sugar and the temperature of water will affect the activity of yeast. Thereby, we set up three groups of controls, which means eight experimental specimens, in order to get the results of the experiment. According to our teacher's suggestions, we added the experimental materials into ziploc bags and observed the expansion and the extent of expansion. This is not the first experiment we have done, but it still makes us feel newly fascinated.
Among the homework of different subjects, the chemistry experiment is the most unique one. It not only improves our hands-on ability but also strengthens our self-learning ability, which benefits us a lot. This homework makes us interested in common items in our daily life and tells us that we should find more interesting science in our lives.
This event was what all of the students in Biology 12 had been waiting for — The Egg Osmosis Lab!
In order to help students better understand the concept of cell membrane and osmosis, our lovely Biology teacher, Mr. C, designed a lab which was related to eggs.
The students were divided into groups of three, and the entire experiment lasted for more than 96 hours. A raw egg, vinegar, water, and honey were given to each group. These three solutions have different densities. Students were required to use a string to measure the circumference of the egg and weigh the initial mass of the egg. The raw egg was first put into vinegar for 48 hours, then removed from the solution; its circumference and mass were measured after the reaction. The egg was then soaked in honey and then water respectively. Finally, the circumference and volume of the eggs and the volume of the remaining water were measured.
Because this was a long experiment, the whole experiment was divided into several parts, and each part was set especially for one solution. The condition of the eggs varied, so every time when we went to the lab, we all felt excited and couldn’t wait to find out what’s going on.
At first, the shell had the colour of a regular egg, and the surface felt smooth and hard. When it was gently released into vinegar, bubbles started to appear on the surface of the shell. This was because the calcium carbonate in the shell reacted with the acid and formed carbon dioxide gases. Then the beaker was sealed with plastic wrap. Two days later, when students returned to the lab, we found that the egg, which originally sunk to the bottom of the beaker, now floated on the surface. It was surrounded by a layer of bubbles, and the egg shell disappeared. The egg became a translucent orange color and had the smell of vinegar. Then the egg was put in the thick honey, and after two days, the color of the egg turned deeper, the egg yolk became clear, and the volume was a little smaller than it was before. In the last stage, the egg was immersed in water for two days, and finally the volume of the eggs increased, and the color became translucent. At that time, when we touched the egg, it no longer felt soft, but slightly elastic.
After the last step was done, we were asked to "destroy" our eggs. This task made many of us feel sad. Some said that, after such a long time, they had already developed a close relationship with their eggs, and that it would be such a pain when it leaves them. One team accidentally broke their egg and shouted: "Ah! My baby!"
Although everyone had to write a complicated lab report after the experiment, there was no complaint of that. We were impressed by the knowledge that we had learned through experiments and personal experience, and we all enjoyed this way of study.
Homework can be like this?
The winter holiday that students are looking forward to is coming! During the holiday, homework is essential. Students in Grade 10 not only have some written homework, but also have some special homework. The homework called “Red Packet” from Ms. Gu is a novelty for many students.
This holiday homework is related to the Spring Festival
The Spring Festival happened during the winter holiday, and was related to giving the red packet during the Spring Festival, which is a tradition in China. It’s usually handed out to the younger generation by their parents，grandparents or relatives. Children usually get red packets on New Year’s Eve after they give their new year’s wishes to their families. Generally speaking, there is money in the red packet, but this “Red Packet” is different, but why?
This time, students were asked to make a special “Red Packet” for their family members. The students who always receive red packets from their parents have a chance to give back! We were instructed to record this process using a photo and write some words to describe it. At the same time, people who receive this “Red Packet” should share their feelings. Students in Grade 10 had different ideas: some people helped their mom do the housework, one student sang a song with her father, some people cooked delicious dishes for their parents, and some people gave a big hug to their grandparents……
All kinds of “Red Packets” make the holiday more colorful, they make the cold winter become warmer, and they bring love and sweetness to our Spring Festival. I’m sure the parents were moved when they received the “Red Packet”. This homework not only improved the thinking ability of students, but also gave students a chance to repay their parents. Everyone likes this kind of homework.