CE Daily Challenge #05

What is TRANSPIRATION?

• water evaporating from leaves

• water ‘crossing’ into the root hair cells

• water passing from the large intestines into the blood

• water moving from the ground into the sea

Answer explanation

Water evaporates from leaves so water can be drawn up a plant... Also features in the water cycle...

Why is a BEE (an insect) an example of an ARTHROPOD?

• it has 6 legs

• it has 3 body parts

• it has a hard exoskeleton

• it is small and reproduces quickly

Answer explanation

Insects have 6 legs, 2 pairs of wings, 3 body parts and antennae BUT...

to be an ARTHROPOD, it needs a hard EXOSKELETON (jointed legs and feets)

What gas is produced when POTASSIUM PERMANGANATE (KMnO₄) thermally decomposes on heating?

• oxygen

• carbon dioxide

• manganese oxide

• hydrogen

Answer explanation

Purple crystals give off oxygen (which can relight a glowing splint..)

How could you prove that an object is made of metal?

• see if it is magnetic

• test its electrical conductivity

• see if is ductile

• see if it sinks

Answer explanation

metals are conductors, ductile, sonorous, flexible and have alkaline oxides (note only 3 are magnetic)

Which of these is a RENEWABLE ENERGY source?

select 2

• coal

• gas

• biomass

• oil

• tidal

Answer explanation

Renewable means easily replaced in our lifetime...

How does LIGHT TRAVEL?

• straight lines

• quickly

• in beams

• out from our eyes

In the alps, a mountaineer shouts a ‘yodel’ and hears his echo 6 seconds later. If sounds travel at 300m/s, how far away, in meters, is the other mountain?

do not include the units

Answer explanation

SiDoT - in 6 s sound would travel D = SxT = 300x6 = 1800m

BUT it is an echo - there and back so... 1800/2 = 900m

In an experiment timing a ball to fall 1 m to the ground using stop watches, it is difficult for 5 people to get the same reading. Why?

• different stopwatches give different readings

• they are stood in different positions

• the ball may bounce differently

• human errordroppin d

Answer explanation

Human error - we cannot accurately start and stop the stop watch... To make this more accurate, do lots of readings and take an average...