Spinning planet(Science project)

Spinning planet(Science project)

The Earth is like a giant ball spinning in the darkness of Space.

The only light falling on it is the light of the Sun glowing 150 million kilometers away.

The Earth turns once a day, and it orbits the Sun once a year.

The experiments on these pages investigate the two ways of moving, and explain why night and day, and the seasons, occur.

The ball represents the Earth and the torch the Sun.

In the final project, you can make a simple thermometer using water to record changes in temperature from night to day and from season to season.

Variable sunlight

The Sun’s light does not fall evenly over the Earth because our planet is round.

Imagine three identical beams of sunlight falling on the Earth. One falls on the Equator and the others on the North and South Poles.

The beam falling on the Equator covers a much smaller area, so its energy is more concentrated and the temperature Is higher.

YOU WILL NEED

Night and day: felt-tipped pen, plastic ball, piece of thin string, non­-hardening modelling material, torch.

Night and day

(1)

Draw or stick a shape on the ball to
represent your country. Stick the string to the ball with modelling
material.Tie the string to a rail, such as
a towel rail, so that the ball hangs freely.

(2)

Shine the torch on the ball. If the
country you live in is on the half

of the ball in shadow on the far side,
then it is night because it is facing
away from the Sun.

(3)

Your home country may be on the
half of the ball lit by the torch

instead. If so, it must be daytime here
because it is facing the Sun. Keep the
torch level, aimed at the middle.

(4)

Turn the ball from left to right. As
you turn the ball, your country will

move from the light half to the dark
half.You can see how the Sun comes
up and goes down as the. Earth turns.

Solar power

The Sun pours energy on to the Earth as heat and light.

The amount of energy received in any one place on the Earth changes with the seasons.

This is because the Earth’s axis is tilted. In summer, one half of the Earth tilts towards the Sun, and is warmer.

In the winter, it tilts away from the Sun and is colder.

The seasons

YOU WILL NEED

The seasons: felt-tipped pen, plastic ball, bowl just big enough for the ball to sit on, torch, books or a box to set the torch on.

(1)

Use the felt-tipped pen to draw a
line around the middle of the ball.

This represents the Equator. Sit the
ball on top of the bowl so that the
Equator line is sloping gently.

(2)

Put the torch on the books so it
shines just above the Equator. It is

summer on the half of the ball above
the Equator where the torch is shining,
and winter on the other half of the world.

(3)

Shine the torch on the Equator. It
sheds equal light in each hemisphere.

This is the equivalent of spring and
autumn, when days and nights are of
similar length throughout the world.

Make a thermometer

YOU WILL NEED

Make a thermometer: water, bottle, food colouring, clear straw, reusable adhesive, card, scissors, felt-tipped pen.

(1)

Pour cold water into the bottle until it is about two-thirds full. Add some food colouring. Dip the straw into the water and seal the neck tightly with reusable adhesive.

(2)

Blow down the straw to force
some extra air into the bottle.

After a few seconds, the extra air
pressure inside will force the water
level to rise up the straw.

(3)

Cut the card and slot it over the
straw. Let the bottle stand for a

while. Make a mark on the card by the
water level to show room temperature.
Take your thermometer outside.

(4)

On a hot day, the Sun’s heat will make the air and water expand,forcing the water level in the straw

above the room temperature mark.Cool the thermometer in the fridge. Mark the different levels.

Engine power

Engine power

 

Imagine having to walk on road everywhere, instead of riding in a car.
Engines are machines that use fuel to do work for us and make life easier.
Fuel is a substance that has chemical energy stored inside it.
The energy is released as heat by burning or exploding the fuel in a engine.

Most cars have petrol engines.
A mixture of air and petrol is pushed into a hollow chamber called the cylinder.
A spark from a spark plug makes it explode, which pushes a piston down inside the cylinder (see below).
This movement is used by gears to turn the wheels.
Most cars have four or six cylinders.

(This shows the foil—stroke cycle of a petrol engine.)
(I Air and petrol mixture is sucked into the cylinder)
(The piston moves up and squeezes the mixture)
(A spark from the plug makes the mixture explode)
(The piston rises to push waste gases out of the cylinder)

A diesel engine works in a similar way, but without sparks.
The mixture of air and diesel is squashed so much in die cylinder that it becomes hot enough to explode.
Diesel engines are used where lots of power is needed, in trucks, diggers, tractors and big trains.

(Jet engines are very powerful. They use a mixture of dir and fuel to push the plane forward at high speed.)

A jet engine mixes air and kerosene and set fire to it in one long, continuous, roaring explosion.
Incredbly hot gases blast out of the back of the engine. This push the engine forward — along with the plane.

An electric motor passes electricity through colls wire.
This makes the coils magnetic, and they push or pull against magnets around them.
The push-pull makes the coils spin on their shaft (axle).

Engines which burn fuel give out gases and particles through their exhausts- Some of these gases are harmful to the environment.
The less we use engines, the better.
Electric motors are quiet, efficient ami relieble but they still need fuel to make the electricity at the power station.

QUIZ

What type of engine is found in these vehicles,Is it a Jet engine, an electric motor, a petrol engine or a diesel one?

1. Cable-car
2-. Formula I racing car
3. Fork-lift truck
4. Land-gpeed record car

When science is hot !

When science is hot !

fire! flames! burning! Heat!

The science of heat is important in all kinds of ways. Not only do we cook with heat, but we also warm our homes and heat water. Burning happens in all kinds of engines in cars, trucks, planes and rockets. It is also used in factory processes, from making steel to shaping plastics.

Heat moves by conduction.

(A A firework burns suddenly as an explosive, with heat, light and sound… BANG)

A hot object will pass on, or transfer, some of it’s heat to a cooler one. Dip a metal spoon in a hot drink and spoon handle soon warms up. Heat is-! conducted  from the drink, through the metal.

Heat moves by invisible ‘heat rays’.

( Metal is a good conductor of heat. Put a teaspoon in a hot drink and feel how quickly It heats up.)

This is called thermal radiation and the rays are infrared waves. The Sun’s warmth radiates through space as infrared waves, to reach Earth.

burning, also called combustion, is a chemical process.

Oxygen gas from the air joins to, or combines with, the substance being burned.The chemical change releases lots of heat, and usually light too. If this happens really fast, we call it an explosion.

Temperature is a measure of how hot or cold something is.

( A thermometer may be -filled with alcohol and red dye. As the temperature is goes up, the liquid rises up its tube to  Show how hot it is. It sinks back down if the temperature falls.)

It is usually measured in degrees Fahrenheit (°F) or Celsius (°C). Water freezes at 32°F (0°C), and boils at 212°F (100°C).We use a thermometer to take temperatures. Your body temperature is about 98.6°F (37°C).

Heat moves by convection, especially through liquids and gases.

(See how hot air shimmers over a candle.)

Some of the liquid or gas takes in heat, gets lighter and rises into cooler areas.Then other, cooler, liquid or gas moves in to do the same. You can see this as ‘wavy’ hot air rising from a flame.

CARRYING HEAT

You will need:

wooden ruler

metal spoon

plastic spatula

heatproof jug

frozen peas

some butter

Find a wooden ruler, a metal spoon and a plastic spatula, all the same length. Fix a frozen pea to one end of each with butter. Put the other ends in a heatproof jug. Ask an adult to fill the jug with hot water. Heat is conducted from the water, up the object, to melt the butter.

Which object is the best conductor?

Answer Give by comment.

When science is hot !