Australian_Science_Illustrated_Issue_52_2017

Editor: Malene Breusch Hansen

scienceillustrated.com.au | 19

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The power of a car engine is measured by means of

metal rolls when the car’s driving wheels are

placed on the metal rolls. When the wheels rotate,

the rolls rotate at the same speed. The rotation is

recorded by an instrument known as a

dynamometer, which registers the wheels’ torque

and rotations per minute.

The data is used by a computer to calculate the

HP of the engine based on a formula. 1 HP is the

equivalent of about 736 watts – the physical force

needed to lift a mass of 75 kg 1 m vertically above

the ground in one second. In spite of the name, 1

HP is not the equivalent of the power of one horse.

The animal can produce 2.5-10 HP.

How is horsepower measured?

Do dogs and

cats dream?

Scientists have discovered brain

activity similar to human dream-

states in cats, mice, and rats, as

they passed through a maze and

when they slept. This indicates

that the maze experience was

relived in the dreams. Dogs show

similar evidence of dreaming. Two rotating metal rolls measure the HP of

a car engine.

DOG-SAVVY

RHEASILVIA MONS

Vesta asteroid

Height: 22 km.

A central mound from a

meteor strike is 200 km wide.

EQUATORIAL RIDGE

Saturn's moon Iapetus

Height: 20 km.

Formed by shockwaves from

an enormous impact.

ASCRAEUS MONS

Northern hemisphere, Mars

Height: 18.2 km.

The mountain is the highest of

3 major, connected volcanoes.

BOÖSAULE MONTES

Jupiter's moon Io

Height: 17.5 km.

The highest point on this moon

was mad by plate tectonics.

OLYMPUS MONS

Mars

Height: 25 km.

But the slope is so gentle, you

might not notice it!.

The highest peaks of

the Solar System?

TOP 5

?

ARNO MASSEE/SCIENCE PHOTO LIBRARY

JEFF DIENER/GETTY IMAGES

Water boils faster at a low pressure

The lower the air pressure of the surroundings, the lower the temperature
of the water in the pot, before water molecules evaporate from the surface,
and the liquid boils.

HIGHER PRESSURE

71 °C 71 °C

WATER VAPOUR

LOWER PRESSURE

The water does not boil

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At sea level, the air pressure is about

one atmosphere, meaning that the

liquid must be heated to 100 degrees,

before the water molecules can evaporate.

The water is boiling

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At the top of Mount Everest, the

pressure is about 1/3 atmosphere. The

lower pressure holds less "on to" the water

molecules, which evaporate at a

temperature of 71 degrees.

Low boiling point =

longer cooking

When water is heated to boiling

point, the temperature of the liquid

stops rising. Boiling water at the

top of Mount Everest can only

become 70 degrees hot, and so,

potatoes must boil for a longer

time on the mountain than in

100-degree water at sea level.

100 °C

71 °C

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TEMPERATURE

BOILING TIME OF POTATOES

AT SEA LEVEL ON A MOUNTAIN

BOILING POINT

ALAMY/IMAGESELECT