Unit 4, Listening 1, Gravity at Work

Gravity at Work

Professor:           OK, in your assigned reading you learned about Newton’s law of gravitation. To summarize, gravity is a force of attraction between objects. So, when I drop this pencil and it falls to the ground, the pencil is “attracted” to the ground because of gravity. Remember, the ground is also attracted to the pencil. Thanks to Newton’s laws, we know that objects that are bigger have greater forces of attraction. That’s why the pencil, which is small, falls toward the Earth, which is big, and not the other way around. Newton also showed that the closer objects are to each other, the attraction is stronger. That’s why the pencil falls to Earth and doesn’t go flying out into space to a bigger planet like Jupiter, which is millions of miles away. Hopefully this is clear for all of you.

For homework, I asked you to each prepare a short presentation about an innovative way scientists and inventors are using gravity. Most importantly, I asked you to answer three questions: Where did the idea come from? How does the invention work? And what’s the science behind it? So, let’s get started on the presentations. Nydia, can you please go first?

Nydia:   Ah, sure. Uh, today I am going to talk about an exciting new invention called GravityLight. Where did the idea for GravityLight come from? Well, the inventors, Jim Reeves and Martin Riddiford, were trying to find a cheap alternative to dirty and hazardous kerosene[1] lights that are used throughout the developing world. They considered lots of different lights, but there was always a problem with the battery[2]. Their intention was to get rid of the battery completely. Batteries are just too expensive, and people can’t always afford them. That’s why many people around the world have been using kerosene lights for years: because they have been the cheapest way to light your home. But they can cause fires really easily, and the smoke can be poisonous. So, Reeves and Riddiford wanted a light that didn’t need batteries but was also affordable. So, they invented GravityLight.

OK, so, how does GravityLight work? Essentially, to turn on GravityLight, you need to lift a weight that is attached to a small generator[3] and a light. As the weight slowly falls, it turns a gear, which drives a generator that powers the light. You get 20 minutes of light every time you lift the weight.

What is the science behind this? This is a bit complicated, but inside the GravityLight, there are plastic gears. The gears control how quickly the weight falls. They also turn on the generator, which runs on a rubber band and powers the light. I think this is a really important invention because it can provide people with a healthy, safe, and cheap alternative to kerosene lights in their homes. It has already been sold in countries like Kenya.

Professor:           That was really interesting! Thanks, Nydia. Now, um, Rowan, can you please come up to the front of the room and go next?

Rowan: OK. My presentation is about a machine called Mr. Trash Wheel. First, I will tell you where the idea came from. Mr. Trash Wheel’s home is Baltimore City in the United States. This city has had a problem with garbage in its harbor for many years. People have always thrown garbage on the street, or maybe it blows out of someone’s garbage can. Then, when it rains, the rain carries the garbage into the harbor. After a strong storm, you could see all sorts of trash in the water. It was unacceptable.

So, this guy, John Kellett, is a sailor and an engineer in Baltimore. He worked for years in the harbor. He was tired of seeing all the garbage in the water, so he worked with the Waterfront Partnership of Baltimore to build a trash wheel.

Next, I am going to explain how Mr. Trash Wheel functions. It’s a big waterwheel that sits right in front of where the Jones Falls River empties into the harbor. It’s surrounded by floating tubes that direct the trash into the machine. When rain falls, water and trash stream down the river to the harbor. The running water pushes the waterwheel and turns it. The wheel is connected to these fork-shaped parts that also turn and pick up the garbage from the water and put it onto a conveyor belt[4] that is also powered by the wheel. The trash moves up the conveyor belt and falls into a big box. So the trash goes into the box and not out into the harbor. The conveyor belt is covered by a white cloth, and on top are solar panels. There are also two big eyes because the conveyor belt kind of looks like a mouth.

OK, so finally, I want to talk about the science behind this invention. Gravity pushes the water down toward the harbor. The force of the water pushes the big waterwheel, which turns the “forks” and the conveyor belt. I love this invention because it’s doing a pretty good job of helping to keep the Baltimore harbor clean. It’s already taken more than a million pounds of trash out of the water! It’s kind of cute, too.

Professor:           Great job, Rowan! OK, let’s go ahead and take a short break. When you come back, we’ll continue with the presentations.


[1] kerosene: noun a type of fuel oil that is made from petroleum

[2] battery: noun a device that is placed inside a car engine, clock, etc. and that produces the electricity that makes it work

[3] generator: noun a machine for producing electricity

[4] conveyor belt: noun a continuous moving band used for transporting goods

Comments

Post a Comment

Popular posts from this blog

Unit 5, Listening 1, Part 1: Urban Settlements

Part 1: Urban Settlements Narrator:        Almost 180,000 people move into cities each day. And now, for the first time in human history, the majority of the world’s population live in urban settlements . Urban settlements can be as large as megacities like Tokyo in Japan, with 35 million inhabitants . . . or as small as the city of Canterbury in the United Kingdom, home to little more than 40,000 residents. And yet, they have many similarities. Every urban settlement has a central business district in its historic core . This trading district is always situated where several main roads meet, and is the primary location for shops, offices, restaurants, and entertainment. High land value means few people live here. This is the main difference between the central business district and other urban zones. During the Industrial Revolution, many towns experienced a massive [1] influx of industry workers. These workers and their families ne...
Read more

Unit 7, Listening 2, Change Is in the Making

Change Is in the Making Kevan Gilbert: Welcome to Change is in the Making , Domain7’s podcast where we explore all things digital through the lens of purposeful change. I’m Kevan Gilbert. Veronica Collins: And I’m Veronica Collins, and together, we’ll be discussing themes of connection making and culture shaping. We’ll be delving into [1] how to create meaningful change from a business standpoint and a human perspective. Gilbert:           Today, we’re looking at the exploding reality of quote, unquote “digital transformation.” . . . Collins:           But I saw somebody call it a digital revolution the other day instead of digital transformation, and that really seems to ring true, that we’re living through, in the same way that the Industrial Revolution [2] completely reorganized people’s lives. We’re living through a digital transformation in that way— Gilbert:   ...
Read more

Unit 6, Listening 2, America’s Magnet for Innovation and Investments

America’s Magnet for Innovation and Investments Renee Montagne, Host: Think of the most technologically innovative companies of the last 50 years—Intel, Apple, Google, Facebook, Twitter. Each one has a Silicon Valley address, and each one got backing from venture capitalists . Over the last decade, more than a third of the nation’s venture capital has gone into Silicon Valley, and much of it has come from there, as well. In our series on the history of Silicon Valley, NPR’s Laura Sydell has this story on how venture capital and high tech grew up together. Sydell, byline: When tech entrepreneurs go looking for money, they can easily end up here: University Avenue in downtown Palo Alto, with its clean brick sidewalks and high-end boutiques. Bill Reichert is a venture capitalist. Reichert:       Within five blocks of here, there are probably between 30 and 40 venture capital firms. And there are probably also about 30 or 40 start-up companies that have b...
Read more