Category Science

Seeds contain everything needed to form a new plant. To do that, they need to be scattered away from the parent plant to a new place on the soil where they can grow. Different types of plant have different ways of spreading their seeds. Some need animals to move them, while others use wind or even fire to scatter them.

Blow in the wind

Some plants have very light seeds and so can use the wind to spread them. This dandelion has seeds with tiny parachutes that allow them to be carried away when the wind blows.

Tasty treats

Many plants have seeds that are hidden inside tasty fruits, such as berries. When an animal eats the fruit, the seeds pass through its body unharmed and are released in its droppings.

Sticky seeds

Animals can carry seeds away from plants without even realizing it. Sticky seeds will fix on different parts of their body, while some seeds, called burs, have little hooks that attach to the animal’s fur.

Exploding pods

The Himalayan balsam plant keeps its seeds in pods. These pods explode when they are ripe, shooting the seeds out of them. The explosion can scatter the seeds up to 7 m (22 ft) away, often startling unsuspecting passers-by.

Earth, wind, and fire

Some plants have more dramatic or unusual ways of spreading their seeds. Fire may kill the parent plants, but it leaves behind fertile ash for their seeds to grow in.

Heat treatment

Jack pine cones are glued shut with resin. When a fire sweeps through the trees, the resin melts and the seeds are released.

Desert rover

Tumbleweed is the dried-up top part of some plants. It rolls around the desert whenever the wind blows, scattering its seed as it goes.

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Plants make their own food using sunlight. Most plants are held in the ground by their roots, and have green leaves. There are thousands of types of plants, ranging from huge oak trees to small ones like this fuchsia.

Roots

Plants usually grow in the earth or soil. The roots dig deep into the ground, keeping the plant in place. They also soak up mineral salts and water from the soil.

Stem

The stem supports the leaves and flowers holding them up towards the light. The stem also carries water and nutrients in the form of mineral salts from the roots to the rest of the plant.

Leaves

Plants use their green leaves to capture energy from the Sun’s rays. The leaves use this energy, together with carbon dioxide from the air, and water, to make food for the whole plant.

Flowers

Most plants have flowers for reproduction. They have male pollen and female eggs, which join together to make seeds.

Berries

Fruits, such as berries, are the parts of flowering plant that contain seeds. Once in the ground, the seeds will grow into new plants.

Why we need plants?

Nearly every animal relies on plants in some way or other. Some animals, called herbivores, eat only plants. Human grow lots of types of plants just for their flowers. Some types of tree are grown for their wood.

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All living things have certain characteristics in common. To count as being alive, a living thing has to be able to carry out seven different processes, which are listed below.

Movement

All living things can move on their own. Even plants have leaves that turn to face the Sun.

Reproduction

Living things can produce new versions of themselves.

Sensitivity

Living things can detect and respond to changes in the world around them. For example, the ability to react to changes in light, or to hear sounds.

Growth

Living things get bigger as they get older until they reach their full size.

Respiration

All living things turn food into energy, using oxygen from the air.

Excretion

All living things must get rid of any waste that they produce.

Nutrition

All living things need food. Unlike animals, plants make their own food.

Animal

Animals can move from place to place. They cannot make their own food, so they rely on eating other living things to survive.

Plant

Plants are fixed in the ground, but their roots, leaves, and flowers can move. They make their own food by using the Sun’s rays.

Fungus

Funguses may not look alive, but they are. Most funguses feed on the remains of dead plants or animals. Mushrooms, toadstools, and moulds are all funguses.

Tree trunk

When a tree dies it usually falls to the ground. Funguses can grow on the dead tree trunk and soak up its nutrients.

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Magnets are objects that produce an invisible force called magnetism. When two magnets are close to each other they produce pushing or pulling forces on one another. Magnets can also pull on, or attract, other objects that are made of magnetic materials, such as iron. Magnets are often U-shaped, like a horseshoe.

Magnetic poles

Magnets have two ends, or poles, called a north pole and a south pole. Unlike poles pull on each other, or attract, so a north pole pulls a south pole. Like poles push on each other, or repel, so a north pole pushes another north pole away.

Magnetic materials

Iron is a magnetic material, so any metal with iron in it, such as steel, will be attracted to a magnet. Nickel and cobalt are also magnetic metals.

Non-magnetic materials

Magnets have no effect on non-magnetic materials. Non-magnetic materials include all non-metals, such as glass, plastic, or wood. Most metals are also non-magnetic, including gold, aluminium, and copper.

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An electrical circuit is a loop around which electrical energy can move. Electricity travels from a power source, such as a battery, through wires, and back to the power source. In a simple circuit, other useful items that make use of the electricity, such as a bulb or a buzzer, are added. Electricity can only flow when there is a complete circuit.

Battery

A battery stores electrical energy and releases it when connected to a circuit. The battery will eventually run down and will have to be replaced.

Switch

A switch allows the bulb to be turned on or off without removing the battery. When the switch is closed, the circuit is complete and the bulb lights up.

Wires

Electricity flows around the circuit through a series of wires. Wires are usually made of copper, as copper is a good conductor of electricity.

Bulb

As electricity flows through the bulb, the electricity energy is converted to light energy, and the bulb glows brightly.

Conductors and Insulators

Conductors allow electricity to flow easily through them. Metals, such as copper, are good conductors of electricity. Electrical wires are made of metal so electricity can flow easily through them. Insulators do not let electricity pass through them. Plastic, rubber, and wood are good electrical insulators. Wires are coated in plastic to prevent you from getting an electric shock if you touch them.

Switching on!

Many electrical items do not need batteries as they can be plugged into the mains, using a long wire. Once they have been plugged in, these items are usually turned on by passing a switch, which completes the electrical circuit.

Picture Credit : Google