GCSE Physics

What to keep same in thermal insulation practical

use the same (start) temperature for each experiment use the same/number of layers of insulation/ or

use the same thickness of insulation(1)

• so that temperature difference can be compared(1)

:

:

:

use the same volume of water(1)

so (total thermal) energy of water is the same (each time)

Or

so the same area of the bottle surface is heated by the water(1)

use a lid for each bottle(1)

so evaporation is reduced / stopped or

so energy loss from the water (surface) is reduced / stopped(1)

repeat the investigation and calculate mean values so anomalous results can be identified or(1)

so the effect of random errors is reduced(1)

Explain how oiling effects efficiency

Efficiency increases(1)

Because percentage/proportion/amount of energy usefully transferred would increase (1)

Because less work is done against friction(1)

Why people should use energy efficient

More efficient devices waste less energy(1)

Which would munise the energy/electricity demands (1)

The actual maximum height reached will be lower why?

Air resistance (1)

Not all elastic potential energy will be transferred to gravitational potential energy (1)

Explain why improves reliability (graph question)

in the summer the power output from the hydroelectric generator is

lower but the solar power output would be greater(1)

so less variation in total power output (which improves the reliability

of the supply)(1)

Independent and dependent variable: thermal insulation practical

In: type of insulation

Dependent: time taken

Why is regular thermometer more likely to be misread than digital

Parallax error

Thermal conductivity

Temp decrease in shorter time means higher thermal conductivity

Bc rate of transfer is higher

Why is there variations in power output

Level of water varies/amount of rainfall varies

And is lower in summer months

SHC practical- why leave thermometer in for a little while

So the thermometer can reach same temp as block

Which bungee should person use if lager weight

One w Greatest extension before snapping

Why does having a large spring constant do to extension

Makes it smaller

Variation in thermal conductivity practical

Variation in mass of ice cube

Variation of room temp

Variation in initial temp of metal block

Why can solar panels not meet UK demands

a really large area of land would need to be covered with solar cells(1)

due to the low useful power output of the solar cells allow due to the low efficiency of the solar cells or

number of hours of daylight is too low (in UK) (1)

or

low solar intensity (in UK)

or

solar radiation (in UK) is too low

or

material for construction of solar cells and/or

lithium batteries is in limited supply

Compare environmental impacts of wind and tidal

• wind turbine is much larger than the tidal turbine

• wind turbine causes more visual pollution than the tidal turbine

• tidal turbine is hidden from view (as it is under water)

• tidal turbine is less likely to cause noise pollution (as it is under water)

• wind turbine is likely to make more noise

• wind turbine needs more raw materials (for construction)

• more wind turbines needed for same power output (at the same flow speed)

• wind turbine will harm birds, whereas tidal turbine will not

• tidal turbine may harm fish, whereas wind turbine will not

SHC

• measure the mass of the empty beaker on the balance

• fill the beaker with water and measure the total mass of beaker and water

• mass of water = total mass - mass of beaker

• turn power supply on so heater increases the temperature of the water

• measure temperature change / increase with thermometer

• use joulemeter to measure energy transferred to water

• calculate SHC using E = mcДe

Thermal insulation

• Pour a fixed volume of hot water into a beaker using a measuring cylinder.

• Place a cardboard lid on top to stop evaporation.

• Keep the initial temperature and volume the same each time.

• Put a thermometer through the lid and record the start temperature.

• Start a stopwatch and record the temperature every 2 minutes for 20 minutes.

• Repeat the test with different insulating materials packed around the beaker.

• Keep the thickness of each material identical.

• The best insulator has the smallest temperature drop in 20 minutes.