How do boats float?

How do boats float?

Boats come in all shapes and size, from small canes to giant supertankers. A boat pushes away a certain amount of the water bebeath it. The water pushes back aganist the boat with an upward force, called buoyancy, which is equal to the weight of the displaced water. This upwards force keeps the boat floating.

What is a skyscraper?

skyscraper

The term "skyscraper" was first used in the 1880's to describe a building with more than ten storeys. Today a building isn't considered to be a skyscraper unless it has at least 40 storeys. Humans have constructed buildings for shelter for thousands of years and they come in all shapes and sizes.

Why do objects look different colours?

Why do objects look different colours?

The white light around us is made up of a mixture of different colours of light. The surfaces of objects absorb some colours and reflect others back. Our eyes see only the colours that are reflected. An object that reflects all the colours of light appears white. An object that absorbs all the colours , looks black. A tomato absorbs all the colours except red, which it reflects back to us.

Why worry about extinction?

Why worry about extinction?

There have been five mass extinction events in Earth's history (the last time, 65 million years ago, the dinosaurs vanished). A sixth mass extinction is taking place thanks to humans. As we drive more animals and plants to extinction, we destroy the life support systems that all species depend on-including us.

Monsters of the deep!

Monsters of the deep!

Down in the cold , dark gloom of the ocean depths lurk some  very strange fish. This deep-sea "anglerfish" can  emit light in order to attract prey. It also has flexible bones, allowing the jaws and  stomach to expand and create room for prey twice the size of its entire body.

How do fish breathe?

How do fish breathe?

Fish are vertebrates (animals with backbones) that live in the sea and in fresh water. Like all animals they have to breathe in oxygen. Lungs would simply fill up with water, so instead fish have feathery gills at the back of the head that extract oxygen from water as it flows over them.

Overcoming Nerves

Overcoming Nerves

Even professional broadcasters, Who look thoroughly at ease on camera, admit to nervousness betore a programme starts. Even prize-winning authors doubt the quality of their latest writing. Such nervousness reflects a desirble stimulus, setting the adrenaline flowing as you gird yourself for the fight. If you suffer very seriously from nervous, relieve them by using relaxation techniques, going for a short walk, or going for your material. Above all, remember that your audiences and associates generally want you to succed. They are rarely hostile. They want to be pleased as much as you want to please them.

Tip: Reducing Last Minute Nervous.

Try this breathing exercise to calm your thoughts and dispel tension. Close your eyes. Place one hand on your upper chest, the other on your diaphragm. Breathe in, feeling your diaphragm rise, then breathe out slowly. Repeat several times.