Amy Yang Miu-yuk, 15 Hong Kong Chinese Women's Club College Challenge: Lose weight This week I read a book about a man who made good use of his life before he died. It made me start thinking that I should treasure my fat ... just kidding! I also discovered this week that McDonald's is focusing more on nutrition. There is a food pyramid printed on the sheets of paper that line the meal trays, and leaflets are also available. The leaflets say that McDonald's food contains various nutrients, such as carbohydrates, minerals, dietary fibre and so on. Now I'm wondering why if you eat their food, you can gain weight. My sister joined my get-fit programme this week. I sneered at her, saying that she didn't have enough time left to succeed. But she just burst out laughing and said that I shouldn't be so superficial and that getting fit shouldn't have a time limit. Now two Miss Yangs are having a competition. I must beat her! Inga Choi, 16 CCC Ming Yin College Challenge: Play a Grade Seven piece of music on my trumpet and all the minor scales This week I had a lesson with my music teacher. I played the song I've been practising to him. He said that, on the whole, it was fine. But, he also gave me some advice. He said that when I play the song faster, my rhythm isn't as precise. He said that I need to practise more with the metronome. He also found that one of my fingers does not have enough strength to press the keys. Therefore, when I play the song faster, I have difficulty managing all of the notes. He also suggested I buy a new metronome with a voice and sub-divide function. He said that, although it is quite expensive, it would really help me. Then he taught me another grade seven song. He also taught me a new warm-up exercise. This exercise mainly trains my flexibility. Besides having a lesson, I listened to some trumpet CDs in order to get some ideas for playing my song. I also listened to some jazz and classical songs. Now, I only have two scales left to memorise. I am confident that I can memorise them over the coming week and meet my summer challenge. Mandy Chu Ka-man, 16 SKH Bishop Mok Sau Tseng Secondary School Challenge: Learn how to ballroom dance This week we did a warm-up dance as usual before we started our lesson. Although we had been taught it before, some students couldn't remember all the steps. Therefore, our teachers asked my friend and I to dance in two corners of the room so that the other students could follow us if they forgot the steps. We were really surprised and thrilled that we could help our teachers and classmates! Then we started to learn a new dance, the tango. I thought it was the most difficult dance I have ever learnt. Your body is close to your partner's throughout the dance and sometimes you have to point your leg in between your partner's legs, just like the waltz. However, the music for the tango is brisker than for the waltz. We had to practise much harder to stay in time with the music. Our teachers taught us the steps and about good posture. My friend and I didn't pay much attention to our posture because the steps confused us! Still, we will try our best and I believe I'll have good news for you next week when the summer challenge finishes. Jermaine Wong, 16 St Paul's Convent School Challenge: Find out more about astronomy This week I will tell you about Mercury and Pluto. I'm not sure why I've chosen these two planets, but they just sound cool to me! Mercury is a rocky planet. It has nothing to do with water, as the Chinese translation suggests. It is the planet closest to the sun, so it has a really high surface temperature - up to 450 degrees Celsius! There is nothing like air there. It doesn't have any satellites like the other planets. Pluto is named after the god of the underworld, Hades. It was discovered in 1930 by an American astronomer called Clyde Tombaugh. It is a unique planet so astronomers have had problems classifying it. It doesn't fall into the rock or gas categories like the other eight planets. It is called an ice planet because it is very cold with a surface temperature of -233 degrees Celsius. Some astronomers believe that Pluto was once one of Neptune's satellites, because of the physical similarities between Pluto and Triton (one of Neptune's other satellites). Pluto has its own satellite too, called Charon.