Science 2

Objects are made from materials: a spoon is an object, and the metal or wood it is made of is its material.

An object is a thing, like a spoon, a chair or a mitten.

Some properties of a material can be tested by doing something to it, like shining a light at it or dripping water on it.

Looking tells you some things about a material, but testing tells you more.

The purpose of an object, the job it must do, decides which material it is made from: a raincoat must keep water out, so it is made of a waterproof material.

Every object is made for a job, and the job needs certain properties.

Many objects are made of more than one material: a pencil has a wooden body, a grey core, a metal band and a rubber eraser.

Look closely at an object and you often find several materials joined together.

A material is transparent when light passes through it so well that you can see clearly through it, like the glass of a window.

Shine a flashlight at a material to test whether light passes through it.

A source of light makes its own light: the Sun, a lamp, a campfire and a firefly are all light sources.

Light comes from somewhere.

Sound is produced by vibrations, and a vibration is a rapid back-and-forth movement, like a plucked elastic band shaking so fast it looks blurry.

Stretch an elastic band between your fingers and pluck it.

Sound travels out from its source in straight lines in every direction, so people all around a ringing bell can hear it.

When a bell rings, the sound goes out from it in straight lines in all directions, like ripples spreading from a stone dropped in a pond.

Some plants and animals make their own light, which is called bioluminescence: a firefly flashes on a summer night, and some deep-sea fish glow in the dark.

Bioluminescence means living light.

Stopping the vibration stops the sound at once: a finger on a plucked guitar string stops the note right away.

Pluck a guitar string and it hums.

Earth has four parts that work together: land, water, air, and living things, which are plants, humans and other animals.

Look around a pond and you can find all four parts of Earth.

Water always flows downhill, from higher land to lower land, which is why rain runs off a hill and collects in the valley below.

Pour water at the top of a slide and it runs down, never up.

Earth spins, or rotates, on an imaginary line through its middle called its axis, and one whole spin takes one day.

Earth turns like a spinning top, all the time, even though we cannot feel it.

Earth's parts support life together: a plant grows in soil and takes in water and air, and an animal breathes air, drinks water and eats plants or other animals.

Living things depend on several parts of Earth at once.

Water flows from small to big: small creeks flowing downhill join to make streams, and streams join to make larger rivers.

High in the hills, melting snow and rain make tiny creeks.

A life cycle shows the different stages of life that a plant or an animal goes through, in order.

Every living thing changes as it grows.

A frog's life cycle has four stages: eggs laid in a pond hatch into tadpoles, tadpoles grow legs and become froglets, and froglets grow into adult frogs.

In spring, a wood frog lays a clump of jelly-coated eggs in a pond.

Human behaviour can help plants and animals: reducing, reusing, recycling and repurposing mean less is taken from nature and less ends up as garbage.

Reducing means using less, like taking a reusable water bottle instead of buying plastic ones.

A flowering plant grows through stages in order: a seed sprouts, grows into a young plant, becomes a grown plant with flowers, and its flowers make seeds.

Plant a bean seed and watch.

A butterfly's life cycle has four stages: egg, caterpillar, chrysalis and adult butterfly.

A monarch butterfly lays a tiny egg on a milkweed leaf.

Creativity is the ability to make something original, such as a new idea, a new technology, a new tool or a new product.

Creativity means coming up with something new.

Many daily activities include repeated steps: brushing your teeth repeats one small stroke, and tying your second shoe repeats the steps you used for the first.

Look for repeating in everyday life.

Creativity is used to design instructions for games, sports, investigations, recipes and computer programs, because there is usually more than one way to reach a goal.

Every set of instructions was designed by someone.

Repetition simplifies instructions: a step that happens again and again is written once with 'repeat', so 'repeat 4 times: forward 2, turn right' walks a whole square.

Instead of writing 'forward 2, turn right' four times, write it once and say how many times to do it.

Many people create instructions: teachers write the steps for a class activity, parents give steps for chores, students invent game rules, and computer programmers write programs.

Instructions are everywhere, and so are the people who make them.

Investigations are done for different purposes: answering a question, building knowledge, satisfying curiosity or solving a problem.

People investigate for reasons.

Procedures that guide an investigation include asking questions, making predictions, gathering data and reaching conclusions, in that order.

Some procedures come in every investigation.

An investigation is a set of procedures carried out for a purpose: testing materials to find a waterproof one for a lunch bag has a purpose, and so does each of its steps.

An investigation is not just doing things for fun.

Planning an investigation means deciding before starting what to do, what to use and what to keep the same, like using the same amount of water on every paper towel.

Planning comes before testing.

A question for an investigation should fit its purpose: to solve the problem of a leaky lunch bag, the question is 'Which material keeps water out?'.

Start with the purpose, then build the question from it.