Category Kids Queries

Submarines are vessels that can travel underwater. They can also float on the surface of the sea and move like any other ship.

Many submarines are powered by a nuclear reactor. The nuclear reactor creates extreme heat used to turn water into steam. The steam drives an engine that turns the propeller. The propeller pushes the submarine through the water.

Tanks on the sides of the submarine are filled with air or water. They allow the submarine to dive under water or surface on the water. Doors, called vents, on the top and bottom of each tank, open and close, letting in water or air.

While the submarine is on the surface, the tanks are filled with air. To dive, the vents are opened.

To make the submarine surface, the bottom vents are opened. The top vents remain shut. Air is pumped into the tanks to blow out the water. When the submarine reaches the surface again, all the vents are shut.

 

Picture Credit : Google

A ship is a big boat Ships are designed to travel the ocean. They usually have several decks, or floors, below the water level.

Some ships, like cruise liners, are out at sea for a long time. They have places for sleeping, eating, working, relaxing, and bathing. A luxury cruise liner even has a hospital, hair salon, shops, and swimming pools.

Most ships are working ships. They are used to carry goods or cargo.

Freighters carry bananas, cotton, coffee, plastics, and cloth. The cargo travels in big metal boxes. Tankers carry bulk cargo, like crude oil or wheat. The cargo is poured right into the hull.

Some fishing ships are like floating factories. They process and freeze the fish on board the ship. Sometimes these ships are at sea for months.

Some Navy ships have large upper decks. Fighter jets land and take off from this deck. Some Navy ships carry researchers, soldiers, tanks, and even helicopters.

 

Picture Credit : Google

Create your own boat with a few supplies found around the house. Most real boats use sails or motors to make them move across the water, but you can move your boat around a bowl of water using a magnet.

You Will Need:

• a horseshoe or bar
• magnet a large needle pins a plastic lid (from a margarine tub or coffee can)
• a small square of paper decorated as a sail
• a large bowl of water

What to Do:

1. Choose the magnet pole you will use. Use only one pole-north or south. Ask an adult to stroke the end of the magnet down the length of the needle 50 times from the eye to the point. Always rub in the same direction.

2. Test the needle to see if it now has a magnetic pull. Will it pick up a pin? Be very careful since you are using pins and needles.

3. Have an adult rub the needle 50 more times with the magnet. Make sure you use the same pole. Pin the magnetic needle through the paper sail.

4. Fasten the sail in the centre of the plastic lid. Float the raft in the bowl of water. Use the different poles of the magnet to push and pull the raft across and around the water.

 

Picture Credit : Google

Have you ever noticed how the water in the bath rises when you get in? This happens because your body weight pushes the water aside, or displaces it.

What happens when you get into a larger body of water like a swimming pool? You’ll float! Your body pushes aside enough water to equal your weight. But the water also pushes back against your body, so you float! This is called buoyancy. Buoyancy is the upward push of displaced water.

If you could weigh the water your body displaced, it would be equal to the pressure of the water pushing up on your body. The pressure pushing up cancels out your weight pushing down.

So why do some objects sink? Objects that are heavier than the same amount of water sink in water. When you throw a rock into the water, it weighs more than the amount of water it displaces, so it sinks.

 

Picture Credit : Google

People all over the world use trains. There are many different kinds of trains. Some trains pull wagons filled with goods. Cattle, oil, coal, and cars are transported in special types of wagons. Trains also carry container trucks and containers for ships.

Trains that carry people are called passenger trains. Passenger trains have toilets. They sometimes have a dining car so that passengers can eat. Some even have sleeping cars.

Some passenger trains make short trips. Many people travel to work in such trains. These trains are very fast. France and Japan have some of the world’s fastest intercity (between cities) trains.

Tracks keep the train on its path. The motor turns the wheels. The wheels turn on tracks. Most tracks are made of two rails, but some use only one rail.

Trains have many cars linked together. The locomotive provides the power. It is usually the wagon at the front, but an engine can pull or push a train, so sometimes it is at the rear of the train. Trains are powered by steam, diesel fuel, or electricity. Few steam engines are used today. Modern locomotives are faster and cleaner than steam engines. They use less fuel, too.

Tram cars are trains that look like buses. They have one car that holds many passengers. Their metal wheels run on two rails in the street. A cable hangs above the rails. It supplies electric power for the tram.

Subway trains move on tracks underground. They also have a third rail. The third rail provides electric power to make the train move.

 

Picture Credit : Google

A campervan (or camper van), sometimes referred to as a camper, caravanette, or motor caravan, is a self-propelled vehicle that provides both transport and sleeping accommodation. The term mainly describes vans that have been fitted out, often with a coachbuilt body for use as accommodation.

Campervans may be equipped either with a “pop-up” roof which is raised during camping or a fixed roof, either shared with the commercial van that forms the basis of the vehicle (commonly a “high-top” model), or as part of a custom coachbuilt body.

Campervans usually have a small kitchen with a refrigerator (which is often powerable by a choice of gas, battery, or mains electricity) and a two-burner gas hob and grill. They generally have dual-voltage lighting which can work from either a dedicated battery (other than the van battery) known as a deep-cycle or leisure battery, or from AC power, supplied at a campsite via a hook-up cable. Larger models may include a water heater, space heating and air conditioning, a portable toilet and even an internal shower. Smaller models often carry a “porta-potty” portable toilet, and sometimes an external shower which operates within the privacy of an awning.

 

Picture Credit : Google