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Class Clips

# SecondaryScience : Phys: Forces - Contact and Non-contact

Clip description Keywords
A journey to the edge of space (pt 2/3)

Duration: 02:40

Examining the problems caused by changes in atmospheric pressure and temperature when planning a helium balloon ride to the edge of space.

Aerodynamics - reducing air resistance

Duration: 03:30

Aerodynamic principles are used to reduce the drag or air resistance on a cycle rider.

Air pressure

Duration: 01:26

A demonstration of the effects of air pressure.

Air resistance

Duration: 01:59

A brief explanation of what air resistance is and how it can be reduced.

Application of balanced forces

Duration: 04:16

Investigating what makes a comfortable chair by changing the net force exerted on a seat and observing the change in pressure.

Avalanches

Duration: 02:36

A model showing how an avalanche occurs due to different types of snow fall over a period of time.

Balance in zero gravity

Duration: 02:50

Footage of a scientist exploring his sense of balance on board the zero gravity 'vomit comet' training aeroplane for astronauts.

Balanced and unbalanced forces

Duration: 01:17

A description of contact forces illustrating balanced and unbalanced forces when sitting on a chair.

Balanced and unbalanced forces

Duration: 02:36

An explanation of the difference between balanced and unbalanced forces, using a cyclist as an example.

Balanced and unbalanced forces - equilibrium

Duration: 02:02

Balanced and unbalanced forces are demonstrated using eggs, books and seat cushions. The concept of equilibrium is introduced.

Can I escape from quicksand?

Duration: 5:03

Greg Foot investigates why quicksand is dangerous and the forces involved that make it so difficult to escape from.

Could I survive an asteroid strike?

Duration: 05:28

Presenter Greg Foot investigates what would happen if an asteroid collided with Earth. He looks at the risks involved, calculates how much energy would be transferred and explains how our atmosphere protects from all but the largest asteroids.

Escaping from gravity

Duration: 03:43

Brian Cox explains the effects changes in gravity have on the body.

Falling bodies

Two balls of similar size but different mass are dropped and observed landing at the same time. The effect of air resistance is explained using a hammer and a feather, along with NASA footage.

Feeling weightless in salt water

Duration: 00:45

How the buoyancy of water in a salt water pool helps patients to exercise without exerting their full weight on injured joints.

Fizz bang

Duration: 02:00

A demonstration of how to make a film cannister rocket.

Force, pressure and surface area - ballerina vs tank

Duration: 02:51

Describes the relationship between force, pressure and contact area. The imprint of a ballerina on points is compared to the track marks of a Scorpion tank.

Force, pressure and surface area - how sharp is a knife?

Duration: 02:33

Testing the sharpness of two knives. The relationship between the force, pressure, and surface area is explained.

Force, pressure and surface area - shoes

Duration: 01:19

The relationship between pressure, force and contact area, using footwear as an example.

Force, pressure and surface area - stinging nettles

Duration: 02:08

Explains how the hairs of a stinging nettle can pierce skin more easily than a pin.

Friction

Duration: 117

The causes and effects of friction are described.

Friction

Duration: 02:10

An introduction to friction, using a cyclist as an example. Some ways in which friction can be increased between tyres and the road are given.

Gravitational field interactions between Jupiter and its moons

Duration: 05:20

The gravitational field interactions between Jupiter and its moons cause tremendous changes to the surface of Io, one of its moons.

Gravity and air resistance on the Moon

Duration: 00:34

A demonstration of a feather and a hammer falling at the same rate on the Moon in the absence of air resistance.

How air pressure makes drinking straws work

Duration: 01:00

Why does liquid travel up a drinking straw? It's not just because you suck it!

How do helium balloons float?

Duration: 00:49

An explanation of how helium balloons float.

How surface material affects frictional force

Duration: 02:36

A demonstration of how the frictional force exerted by an object is affected by the surfaces in contact with each other.

How the shape of an object affects frictional force

Duration: 01:12

Frictional forces exist in non-solids and change with the shape of an object.

How to reduce friction on ice

Duration: 02:28

A demonstration of how the frictional force between a curling stone and the ice depends on the type of ice.

If the whole world jumped at the same time would the planet move?

Duration: 3:59

Presenter Greg Foot investigates the question that if the whole population of the world jumped at the same time, whether it could cause an earthquake and if it would affect the speed at which the Earth turns on its axis.

Increasing and reducing friction

Duration: 01:08

A brief explanation of how friction can be useful and not useful, using a bike as an example. Ways of increasing and reducing friction are given.

Overcoming friction

Duration: 02:45

A demonstration of the increasing frictional force of an object as a driving force is applied against it.

Pressure changes and decompression

Duration: 03:22

What happens to balloons in a decompression chamber?

Pulp friction

Duration: 02:21

Presenter Dr Yan demonstrates the power of friction with some paperbacks and strong members of the public.

Rescuing a stranded submarine at 80 metres

Duration: 04:26

A Norwegian submarine is stranded 80m underwater. The presenter is on-board a Royal Navy rescue submersible for a navel exercise as it docks with the submarine. The concept of pressure differentials is explained.

Spider-jem

Duration: 03:41

Presenter Jem climbs a sheer BBC building with gloves built from ordinary vacuum cleaners.

Straw submarine

Duration: 02:35

A discussion of the principles of buoyancy and how to make a Cartesian diver.

The Coriolis effect in your bathroom sink

Duration: 02:08

A practical demonstration showing how you can investigate the Coriolis effect using your bathroom sink.

The effect of pressure on bubbles

Duration: 03:38

A practical demonstration using a bicycle pump to put bubbles under high and low pressure.

The effects of fire on air pressure

Duration: 03:32

Simulating the effects of fire on air pressure when the amount of available oxygen changes. A backdraught occurs as an oxygen-starved fire is suddenly given a new supply of oxygen.

The gravitational influence of the Sun

Duration: 03:11

How big is the solar system? A description of the extent of the Sun's gravitational influence on other objects such as comets.

The Venera 4 probe is crushed as it reaches Venus

Duration: 02:46

The Russian Venera 4 probe did not withstand the high atmospheric pressure to reach the surface of Venus before being crushed.

Upthrust in salt water and fresh water

Duration: 03:41

The upthrust on a model placed in fresh water and salt water is compared. One model floats and the other sinks.

Using air pressure to pump water

Duration: 03:27

How atmospheric air pressure is used to help pump water from an open reservoir to a higher level.

Water Bottle Rockets

Duration: 02:43

A practical demonstration using a bicycle pump to make a rocket out of a plastic bottle.

Weight and gravitational field strength

Duration: 00:47

Space, the moon landing and different planets are used to talk through gravity.

Weight, density and upthrust in fluids

Duration: 01:29

A demonstration of the effect of upthrust on masses in air and water and the effect of buoyancy on weights of different density.

Which falls faster?

Duration: 01:34

A demonstration that mass and weight do not affect acceleration due to gravity.

Zero gravity flight

Duration: 04:11

James Burke takes a zero gravity flight in the special plane used by the NASA astronauts.