Misconceptions still abound Questions relating to climate change

ATSE 2011

Keith Ross

Student teachers come to us still with many scientific ideas unclear,

unchallenged and in need of review.

ESCalate http://escalate.ac.uk/1141.

The big ideas• On Earth matter is cycled whereas energy is degraded

• Gases are made of matter – the atmosphere is ‘heavy’ and held

in place by gravity

• Energy from sun arrives as visible light and escapes as IR.

There is a balance. Water vapour and other gases help make

the atmosphere like a natural greenhouse

• Life processes recycle their carbon so CO2 does not build up in

the atmosphere

• Fossil fuel carbon, released into the atmosphere during

combustion, increases CO2 levels, so less easy for IR to

escape. Earth has to heat up to restore the balance.

Understanding matter and energy

When something is dumped on the rubbish tip, goes up the chimney or down the drain: True or false:- Its atoms may….

a. … be used by living things to help them grow.

b. … remain in the environment and cause pollution.

c. … remain harmlessly in the environment.

d. … eventually cease to exist.

Suppose you weighed all the consumer material that enters a typical house (air, water, gas, food, packaging etc) during a year and then you weighed all the material that left the home over the same period (gases up the chimney, through windows etc, liquids & solids down the drain, solid waste into the bin etc.) Would the materials leaving weigh:

a. A lot more than …

b. About the same as …

c. Much less than … the material entering the house

If you were to measure all the energy entering a house over a year (sunlight, heat, energy transferred from burning fuels, electricity, energy from respiration etc.) then you measure all the energy leaving the house over the same period (up the chimney, through the walls, roof, windows etc. as heat, sound light etc.) ...

... would the energy leaving the house be...

a. A lot more than …b. About the same as …c. Much less than … the energy entering

the house

A car made a round trip yesterday. Twenty litres of fuel were used, and the fuel tank is now empty. Where is the energy (measured in joules) today, obtained from combustion of the 20 litres of fuel during the trip?

The energy (in joules):

a. has been dissipated as environmental heat.

b. was used up fighting against air resistance etc.

c. has been stored and is available for use later on.

d. has not been used up, but transferred into sound, air movement, heat etc.

A cyclist completed a round trip of 20 miles yesterday. What has happened to the usefulness of the energy today, that was released from the working of her muscles during the ride, and which 'fuelled' the round trip? The usefulness of the energy:

(Note that this is a different question.) a. is still there as sound, air movement, and heat energy in

the tyres and brakes which the cyclist can use again.b. has been stored and is available to be used later on by

the cyclistc. has gone fighting against air resistance etcd. is still there as environmental heat which the cyclist can

use again

Which of the following is/are powered, directly or indirectly, by replenishable energy from the sun?

a. a bicycle (with rider)

b. a hydro-electric power-station

c. a wood fuel stove

d. a windmill

Consider the following statements about replenishable energy sources. True or false:

a. They are almost all continually replenished by solar energy.

b. In the distant past people relied on them for cooking, farming and transport.

When a car is being driven at a constant 60mph along a flat road what percentage of energy is used to provide kinetic energy to the car?

a. Noneb. A littlec. Halfd. Moste. All

Which one of the following best explains why it is more costly in energy for a train to stop at all stations rather than travel at a constant speed for a journey?

a. Energy is used to operate the brakes

b. More energy is needed to overcome friction when you keep stopping and starting

c. Fresh inputs of kinetic energy have to be used after each stop

Understanding gravity, gases and the atmosphere

A football is about to be pumped up with air. Who is right:

a. I think it will get heavier.

b. I don't think the weight will change.

c. I think it will get lighter

Which of the following statements about the force of gravity are true? Gravity:

a. Pulls things down to the earth b. Is caused by air pressing on us c. Exists on the moon as well as

on the earth d. Pulls together two objects which

have mass

An astronaut is standing on the moon. She releases a feather and spanner together from the same height above the surface of the moon.

Which of the following describes what happens?

a. The feather reaches the ground first.b. They travel together but with

increasing speed (acceleration) c. They travel together at constant speed

(terminal velocity). d. The spanner reaches the ground first.

Which two of the following are good explanations of why a hot air balloon rises?

a. Hot air always rises.

b. Cold air pushes it up.

c. Gravity no longer acts on the hot air.

d. Hot air is buoyed up by the rest of the air.

Understanding the Greenhouse effect

True or false:The 'hole' in the ozone layer:

a. lets heat in and causes global warming b. lets UV in and causes a possible

increase in skin cancers c. It is caused mainly by substances that

are inert (unreactive) at ground leveld. It would eventually repair itself naturally if

left alone

True or false:Energy from the sun:

a. is the energy source that fuels living things

b. reaches us in the form of electromagnetic radiation

c. is absorbed directly by the atmosphere, causing the enhanced greenhouse effect.

d. is the energy source that fuels the weather and climate

Understanding the carbon cycle

Consider the material (stuff, matter, atoms. . .) in our food that enters our blood and which we have used as a fuel (providing us with energy). Which one of the following describes how this material (ie the stuff, matter, atoms)

leaves our body?

a. It comes out as energy, eg movement and heat.

b. It comes out as faeces.

c. We breathe a lot of it out as carbon dioxide and water vapour.

d. The atoms are all used up and only energy is left.

When do plants respire?

a. All the time b. At night onlyc. In the daytime only d. Never

Which of the following are required by all germinating seeds?

a. Oxygen

b. Water

c. Carbon dioxide

d. Light

e. Minerals

f. Soil

g. Warmth

What is the immediate source of energy for a seed to germinate?

a. The sun

b. Carbon dioxide and water

c. Respiration of starch in endosperm

d. The embryo

Which of the following are sources of energy for a plant to grow?

a. Sunlight through photosynthesis

b. Carbon dioxide and water through photosynthesis

c. Glucose and oxygen through respiration

d. Minerals taken up through the soil

Which of the following statements are true?

a. Breathing helps get oxygen to the lungs

b. Breathing is a simpler term for respiration

c. Digestion is where food turns to energy

d. Digestion helps get nutrients into the blood

e. Respiration happens in the lungs

f. Respiration occurs in the cells of our bodies

Which of the following are ways your body removes the waste products produced by chemical reactions in your cells?

a. The lungs remove Carbon dioxide from the blood

b. Faeces are removed via the anusc. Blood is filtered by the kidney and waste

removed as urined. Some material is lost in sweate. It is excreted

What will happen to the weight of a fertilised bird's egg as the chick develops?

a. It gets heavier

b. It gets lighter

c. It stays much the same

Natural organic materials like paper, wool, leather and cotton rot if they are thrown away, but artificial organic materials such as polythene and nylon do not.

This is because:

a. Man-made things are waterproof so cannot rot.

b. Natural materials are chemically completely different and only they can rot.

c. Man-made fibres are stronger than the fibres in natural materials.

d. Microbes have not yet evolved to deal with man-made materials.

Understanding fuels and burning

Many people say that fuels contain energy. How do you imagine energy to be associated with, or to be 'in', fuels?

True or false:

a) When fuels burn the energy trapped in them is released.

b) The energy is not in the fuel itself, but is associated with both the fuel and oxygen.

What is the origin of the energy which is transferred when fuel burns: True or false:

a. Fuels contain energy-rich bonds which release energy when the bonds break.

b. Energy is released when new bonds are formed. This happens during burning.

Suppose you collect everything that comes out of the exhaust pipe of a car on a journey (exhaust gas, fumes, etc.) and somehow press it all together so it can be weighed. Compared to the amount (weight) of petrol used for the journey, the amount (weight) of exhaust (everything that comes out of the exhaust pipe) will be (choose one):

?a. Much lighter because the petrol has been burnt up. b. Much lighter because gases don't weigh anything. c. About the same because atoms cannot be destroyed.d. Much heavier because air has been added to the

petrol.

Contacts - links

• keithaross@gmail.com

• www.scienceissues.org.uk

• http://escalate.ac.uk/1141

• www.ase.org.uk/resources/scitutors

• Teaching Secondary Science – 3rd Edition

Ross, Lakin & McKechnie – Routledge 2010