Wednesday 30 December 2015

The Leaning Tower of Pisa - Galileo's Experiment

I went on holiday to Italy not long ago and whilst I was there, I visited the Leaning Tower of Pisa. This is the place of Galileo’s experiment where he dropped two cannonballs of different masses to see  whether they would hit the ground at the same time. They did. 

Many people would argue that they wouldn’t (if they didn’t know the outcome of the experiment already). This is understandable as common sense tells you that heavier objects have a larger force of attraction and will therefore accelerate towards the Earth faster than lighter ones. However, acceleration is not just derived from force, it also depends on mass (a = F/m, acceleration = force / mass, Newton’s Second Law of Motion). 

Let’s substitute some figures into a = F/m. Take a 1kg chinchilla and 100kg panda. If we were to only think about the force acting on these animals (ignoring air resistance), the panda would hit the ground first. This is because 100kg, the panda’s mass, results in 1000N of downward force (due to the Earth’s gravitational field strength of around 10N/kg). The chinchilla’s downward force would only be 10N. Now let’s put the effect of the animals’ masses into a = F/m.

acceleration = (1000 N / 100 kg) = 10 m/s/s
acceleration = (10 N / 1 kg) = 10 m/s/s













The acceleration is the same regardless of the force. The panda's mass gives it more inertia (this is an object's resistance to changes in its current state of motion), this means it is more difficult to get the panda moving compared to the chinchilla. The panda's mass has an inverse effect on its acceleration and therefore causes the two animals to accelerate at the same rate.

Thursday 24 December 2015

The Physics of Flight

I recently went on holiday to Italy, this required me to fly which got me wondering: How does an aeroplane fly whilst carrying so much weight? I went on a little journey of discovery and found out.

Takeoff

During takeoff, the plane's engines produce a great deal of force (thrust) pointing in the opposite direction of the plane's travel. According to Newton's third law of motion, this makes the plane move forwards (every action has an equal and opposite reaction). Due the movement forward, air is rushing over the plane's wings. The carefully designed shape of the wings forces this air downwards which causes an upward force called lift. This lift is what causes the plane to go upwards and the thrust from the engines is what causes it to move forwards.

Flight

The plane is now suspended in the air. It doesn't fall to ground because the lift produced by the air rushing downwards exactly balances the weight acting downwards. The plane keeps moving forwards because the thrust from the engines is greater than the air resistance.

There you have it, flight in its simplest terms.




Monday 17 August 2015

Buddhist Retreat (YBAT 2015)

This holiday, I attended a meditation course run by the Young Buddhists Association of Thailand. It was designed to be an enjoyable course that blended the practice of sitting and walking meditation, the application of the skills learnt from it and fun activities. They also had speakers come in to teach us about how meditation can help in life.

I learnt a lot from the meditation course and I will try to remember everything and use it to help me whenever I need it.

The first thing I learned from it was that happiness does not come from things outside of yourself or your mind. The example our teacher used was people being sad about something and complaining on Facebook and ranting about it. The teacher said that people who do this are looking for attention from friends and become happy when people give them the attention they want. She taught us that to be truly happy, you must first calm your mind, and watch the breath. The peace you get from not bothering about anything else is true happiness.

One of the games we played to apply the concentration on the breath was to hold a bowl of water which was filled to the brim and walk around the garden and try to spill as little as possible. I remember that when friends walked past me and I looked at them instead of concentrating on myself and my bowl of water, the water spilled and my team would lose. When I cleared my mind and stayed with myself and didn't care about anything else, I didn't spill my water!

Over the duration of the course, a total of 7 speakers came to talk to us. The first was an LSE graduate who regularly practices meditation. He told us about his time in Dulwich College and said that he had many roommates during his time there, he didn't like many of them as they were loud, slept late and didn't take many showers. He was angry at them but he told us that we should forgive
anyone who makes us angry as it makes us feel better about the situation.

The second was a monk who came to talk about the 5 precepts. He said that a good human being has to make sure they stick to the 5 precepts.

The third was a monk who came to teach about how important our lives are and how lucky we are to have so much. He showed us pictures of farmers who were so poor they couldn't afford shoes, and compared it to our lives. We have money to pay for clothes, shoes, and food, we are extremely lucky.

The fourth was a man whose family was extremely rich, they had 3 factories and many houses and cars. As a child he had lots of money to buy everything he wanted. But when he grew up a little, his family started running out of money and had to sell their factories. Then they had to sell their houses and had to rent one. More bad news came their way and he was stuck in jail. Luckily his parents bailed him out. His mum then told him to go on a retreat at his local temple. After doing so for many months, he came back and realised that he needed to do more charity and be more thankful for
he has.

The fifth was a monk who talked about being polite to your elders and how you have to respect them.

The sixth (and my favourite) was a Cambridge graduate called Pam who was the LSE graduate's sister. She came and talked about how meditation can be used in all parts of life. She went to a boarding school called Wycombe Abbey. She said that meditation helped her to concentrate on her studies and not stray from schoolwork. She said it helped her to make the right decisions, her friends started drinking alcohol when she started to become a teenager and she tried it too but she made sure she stopped with the help of meditation. When she finished her GCSEs, she got all A*s in physics, chemistry, biology, maths, English, English literature, French, Spanish and further maths. When she applied for Oxford and LSE, she didn't get accepted and she was very upset but she got back on track and tried harder, and after that she got into Cambridge.

The final speaker was a former model who won the 'Miss Thailand' award. She said that she used to drink all the time and party with her friends. All this had to stop when she found out she had cancer. She spent her time meditating and learning about Buddhism. She realised then that nothing is permanent. Another lesson she taught us was that you should love your parents. When she was ill her mum took care of her even though she was a very difficult child and she even welled up a little when she talked about her mum.

Overall I learnt a lot and will try to use this in my everyday life.

Thank you YBAT, and a special thanks to uncle Boy and auntie Ann.

Monday 27 July 2015

Bird Safari

28/7/15

My grandparents' friends took us to go on bird safari. They took us to a rice field that used to belong to my grandparents. We sat in the back of a pickup and had our cameras at the ready.

We saw many species, I spotted a beautiful brown and blue kingfisher but wasn't quick enough to photograph it. We saw many cranes eating aquatic snails in the paddy fields, there were loads! We even saw weaver bird nests!










My First Time Solo Canoeing

27/7/15

We're currently on holiday in Thailand (my home country) for the summer. Yesterday, my dad took the whole family out canoeing on the River Kwai after finding his old canoe in my grandparents' house.

First, I went with my dad just around the river. He taught me how to do a J-stroke. This helps to keep the boat on course, because when paddling on just one side, the boat moves to the opposite side that you're paddling on, a J-stroke corrects this. I had already learned Indian stroke before and carried on doing this for a while.

My dad left the canoe and let me and my mum go alone. I sat in the front and steered whilst my mum paddled to help the boat gain some momentum. It was fun paddling with my mum! Next my dad told me to go solo. I was quite frightened as I had never been in a canoe alone before. However, after a while, I got used to it and actually did quite well.



The Day I met Professor Brian Cox!!

25/6/15

Today, I met Professor Brian Cox. My head of year leader told me that he was coming to congratulate a group of students at my school for completing a course and decided to let me see him as well as she knew how much I loved physics.

I left my ICT class early to see Brian and on the way knocked on my maths teacher's door, she came with me too as she also likes physics. We made our way into the hall and saw him stood not too far away. One of the teachers who helped to organise the event took me up to the professor and introduced me to him. I was extremely nervous talking to him as he is someone I look up to and we talked about how much I like physics and whether it is something I would consider as a university course option (which I definitely am!) and I got him to sign my book (Why does E=mc²) which was also signed by the other author, Professor Forshaw.

After meeting him, he went away to see the other people. My maths teacher was also dying to see him so another teacher brought him over to where we were standing and he talked to her. I grabbed this opportunity to ask him about nuclear fusion. My question was about tokamaks and how they work. He said that for nuclear fusion to happen, the atoms have to be ionised (stripped of electrons) this means that the net charge of the nuclei is positive (as there will only be protons (positive) and neutrons (neutral) left). The method used with tokamaks is magnetic confinement, this means that they use magnetic fields to contain the positive nuclei whilst they 'whizz' around within, occasionally bumping into other nuclei and starting a nuclear reaction.

It was a pleasure meeting Professor Cox and I hope to see him sometime in the future.


Wednesday 1 July 2015

St Peter's School: Physics Olympics

17/6/15

Today, I went to St Peter's School to take part in a physics competition! Our team comprised of two girls and two boys, all of us are physics geeks. We had a great time meeting like-minded people and having a go at the challenges during the day.

The first challenge we took part in was called 'Payload'. Teams had to design a boat with basic materials like card, a sheet of acetate, plastic bottles etc. and then we had to see how many marbles they would hold. Our boat managed to hold 69 marbles before it sank.

The next challenge was called 'Good Vibrations', in this one, we had to determine the weight of a toy duck using an oscillating ruler and some weights. First we timed how long it took a 50g weight to oscillate 20 times, next we timed a 100g weight and then 150g. We plotted our results on a graph. We then measured how long it took the duck to oscillate 20 times and, using the line of best fit, we found out its weight.

Next, we had to create an electromagnet and see how many paperclips we could pick up. We had a choice of whether to use a core of aluminium, steel, or iron. We were also able to choose how we connected our circuit. The best way to pick up the most paperclips was using a core of either steel or iron and connecting two cells in parallel to the coiled wire around the metal.

Our next challenge was to build a lighthouse using a magazine, wire and a bulb. The aim was to hold a creme egg as far off the ground as possible and connecting the bulb to the top, extra oints were awarded if we were able to get our bulb to flash three times. The strongest and sturdiest lighthouses were made of three rolled up pieces of paper joining in the middle (like a tripod) and another rolled up piece of paper on top of the joint holding the egg. The way to get the bulb to flash was to connect it up but with one side of the wire quite loose and tapping the loose end.

Our final challenge was to create a solar powered boat. We designed the boat and chose the best propeller then charged up our capacitor and let timed the boat.

Throughout the day, all members of the team took part in a Fermi quiz where we had to estimate values to the nearest power of 10. These included the volume of air above the county of Yorkshire, the amount of handcuffs needed to travel the distance of the moon's orbit around earth twice and how many Smarties weighed the same as a hippo. The bonus question was to estimate the amount of Smarties in a container. We were one of five teams to get closest to the answer to the bonus question which was 433 and we one 433 Smarties to share between us.

We didn't win but we definitely had a great time! Thank you to St Peter's for hosting the event and all of the sponsors.