Science Test 27/04/23

Question 1

Sound

Answer 1

Particles vibrate backwards and forwards in the direction the wave is moving. This causes areas of high and low pressure (compression and rarefaction). Since there are areas with different air pressure they are called pressure waves/

Question 2

Ultrasound

Answer 2

Humans can hear sounds with a frequency between 20-20 000 Hz. Ultrasound is anything that has a higher frequency than 20 000 Hz. It can be used to vibrate dirt off things (ultrasonic cleaning) and for physiotherapy.

Question 3

Types of waves

Answer 3

Transverse-vibrate at 90* to the direction which they are travelling and move up, down, forwards and backwards. Longitudinal-vibrate in the direction which they are travelling.

Question 4

Ionisation

Answer 4

This is where electrons are knocked off of atoms in cells which can cause mutations if the dna is affected which can lead to cancerous tumours forming. Ionising waves are gamma, X-rays and ultraviolet rays.

Question 5

Enzymes

Answer 5

These speed up the digestion of nutrients. Each enzyme is specific to each molecule. The way they bond is called a lock and key model. Carbohydrases break carbohydrates into simple sugars, proteases break proteins into amino acids and lipase breaks lipids down into fatty acids and glycerol.

Question 6

Nutrients

Answer 6

Carbs-main source of energy
Lipids-fats and oils provide energy
Proteins-growth and repair of cells and tissues
Vitamins and minerals-essential in small amounts to keep you healthy
Water-needed in all cells and body fluids
Fibre-provides bulk to food to keep it moving through the gut

Question 7

Light

Answer 7

Amplitude- distance between the middle and top/bottom of the wave
Wavelength-the distance between two points on two separate waves
Trough-bottom of the wave
Peak-to of a wave
Frequency-how many waves pass a fixed point per second measured in Hertz (Hz)

Question 8

Light

Answer 8

Angle of incidence = angle of reflection
Speculation is light reflecting off a smooth surface and diffuse scattering is a reflection off a rough surface
Refraction is when a light wave passes through two different substances (it travels at different speeds depending of the substance. When a wave comes from a less dense material to a more dense material it bends toward the normal and the opposite the other way.

Question 9

Light

Answer 9

Light is refracted by the lens focusing it on the retina as a flipped image then your brain flips it again.
Shortsighted people have light focus before the retina and long sighted people have light focus after the retina.

Question 10

What is a sound wave called when it vibrates forward and backward in the direction it is moving?

Answer 10

Pressure waves as they create areas of different air pressure.

Question 11

What frequency of sound can humans hear?

Answer 11

Between 20 and 20 000 Hz.

Question 12

What can ultrasound be used for?

Answer 12

To clean things, to see an unborn foetus and physiotherapy.

Question 13

What is a longitudinal wave?

Answer 13

A wave which vibrates in the direction it is moving.

Question 14

What is a transverse wave?

Answer 14

A wave which vibrates at 90* to the direction it is travelling and moves up, down, forward and backwards.

Question 15

What are some examples of ionising rays?

Answer 15

Gamma rays, X-rays and ultraviolet rays.

Question 16

What do enzymes do?

Answer 16

They speed up the digestion of nutrients.

Question 17

What is the name for the way enzymes bond?

Answer 17

A lock and key model.

Question 18

What do carbohydrases break carbohydrates into?

Answer 18

Simple sugars

Question 19

What do proteases break proteins down into?

Answer 19

Amino acids.

Question 20

What does lipase break lipids down into?

Answer 20

Fatty acids and glycerol.

Question 21

What are carbs for?

Answer 21

They are our main source of energy.

Question 22

What are lipids for?

Answer 22

fats and oils, produce energy.

Question 23

What are proteins for?

Answer 23

Growth and they repair cells and tissues.

Question 24

What are vitamins and minerals for?

Answer 24

they are essential in small amounts to keep you healthy.

Question 25

What is water for?

Answer 25

It is need in all cells and bodily fluids.

Question 26

What is fibre for?

Answer 26

It provides bulk to food to keep it moving through the gut.

Question 27

What is amplitude?

Answer 27

The distance between the middle of a wave and the peak.

Question 28

What is wavelength?

Answer 28

The distance between two points of two separate waves?

Question 29

What is a trough/peak?

Answer 29

The bottom/top of a wave.

Question 30

What happens when light comes from a less dense material to a more dense material?

Answer 30

It slows down and moves towards the normal.

Question 31

How do we see?

Answer 31

Light is refracted through the lens onto the retina creating a flipped image which our brain then flips again.

Question 32

Why do shortsighted/long sighted people need glasses?

Answer 32

Shortsighted people have the refracted ray focus in front of the retina and long sighted people have the refracted ray focus behind the retina so a piece of glass can be used to correct it when at a specific curvature.