Hello again!!

Hi all,

It's been so long! Long story short, sorta locked myself out of this account and thus...well...haven't been able to post hahahaha. All good now:))

It's been like 8 months so let's recap...

For those asking, I did manage to grab A*s in all three of my sciences:)). Despite this though I only carried on with physics and biology...well...and chemistry too...for a bit (long story)...

Basically with the new A level system I started out with 4 (Chemistry, Maths, Physics and Biology) but our school quickly made us cut down to 3 (much to my sadness) so I decided to drop Chemistry because it's simply the one I didn't need as much (regarding my career path).

So here we are now, i'm currently mid-way through 1st year A levels (equivalent to AS year) and it's a bit hell at times but mostly all good. What i'm really getting at in this post is whether anyone would like me to do revision blogs such as this one, and my others, for Biology and Physics A level? (I could also do math, but it may be a bit trickier but if you want, I will:D). For biology I do the AQA spec and for physics I do OCR Physics A (maths is also OCR covering the topics Core 1, Core 2, Statistics 1, Core 3, Core 4, and Mechanics 1).

Even if we take different exam boards, it may be useful since a lot of stuff crosses over all boards.

Have a mull over:) tbh I love to do this for the enjoyment of helping people, so let me know if these blogs have/will help you, and i'll continue them:))

Thank you for all your support,

Millie xx

4.17 describe the advantages and disadvantages of methods of largescale electricity production from various renewable and nonrenewable resources.

NOTE: advantages are in green, disadvantages are in red

Renewable
- hydro-electric power: very expensive, produces small amounts of electricity
- Solar panels: produce lots of energy, rely on weather
- Nuclear reactors/nuclear power: produces lots of energy quickly/easily, produces lots of harmful waste products
- Wind power: visual pollution; produces small amounts of electricity for space and effort in comparison to other methods, makes use of what we have (e.g. a 'free' energy source)

Non-renewable

Fossil fuels: finite source (will run out one day), releases CO2.

7.8 understand that ionising radiations can be detected using a photographic film or a Geiger-Muller detector

Geiger-Muller detectors beep when ionizing radiation is detected. The faster the beep, the more radiation. NOTE: there will always be slow, steady beeps due to background radiation.

Photographic film is white. It absorbs radiation and turns black. NOTE: photographic film is used for X-rays, the bone part is white as the radiation is absorbed by the bone therefore the film behind it s not exposed to the radiation. Everywhere is the film where there is no bone is black as there is nothing blocking the radiation from getting through.

5.3 describe experiments to determine density using direct measurements of mass and volume

1. First, measure the mass of an object (weigh it)
2. Then measure the volume. If the object is irregular (e.g. not a cuboid/easily measurable-shape*, then take a set amount of water (eg. 100ml) and fully submerge the object in the water. Measure the rise of the water (eg. From 100ml to 130ml). Or measure using a eureka can. If object is regular, however, you can measure lengths to find the volume.
3. Use the equation density = mass/volume to find the density

*okay so easily-measurable shape isn't correct English but you get what I mean

4.8 explain how insulation is used to reduce energy transfers from buildings and the human body

NOTE: You only need to learn a few examples, I have included quite a few so you can choose and decide which ones you find easiest to remember.

Buildings

Loft insulation - a thick layer of fibreglass wool laid out across the loft floor and ceiling reduces heat loss from the house by conduction and convection

Hot water tank jacket - Fibreglass wool reduces conduction and convection

Draught-proofing - Strips of foam and plastic around doors and windows stop draughts of cold air blowing in (therefore, they reduce the amount of heat lost due to convection)

Cavity wall insulation - foam squirted into the gap between the bricks stops convection currents and radiation in the gap, the insulating foam and air trapped also help reduce heat loss by conduction

Thick curtains - Reduce heat loss by conduction and radiation

Double glazing - Two layers of glass with a small gap of air in-between them, this reduces conduction and convection

Humans

Hairs - When it's cold, the hairs on your skin stand up to trap a 'thick' layer of air all over the body (which will insulate the entire surface area). This limits the amount of heat loss by convection.

Clothes - reduce heat transfer. Pockets of air trapped between clothes reduce heat transfer by conduction (and a little convection). Also, clothes reduce the amount of heat radiated from the body (this is because the material absorbs some of the heat as it is radiated out of our bodies).

4.6 describe how energy transfer may take place by conduction, convection and radiation

Convection is the transfer of heat by the upward movement of less dense (warmer) gas/fluid and the downward movement of denser, colder gas/liquid. NOTE: convection can not occur in solids or in vacuums

Conduction is the transfer of thermal energy through a solid (the solid doesn't actually move)

Radiation is the transfer of thermal energy in infrared waves. This is also the only method of heat/thermal energy transfer that can occur in a vacuum

3.16 construct ray diagrams to illustrate the formation of a virtual image in a plane mirror

When light rays bounce off an object onto a mirror, a virtual image is formed. A ray diagram shows how this image is produced (in a plane mirror)

Method

- firstly, draw a line from the top of the object to the reflective surface (in this example it is a lake, although it could be a mirror/shiney surface etc)
- reflect the incidence engle in the reflective surface and draw the reflective
 (into a human eye_
- now continue the ray from the eye through the reflective surface until it is in line with the real image.
- repeat with a line from the bottom of the real image.
- the lines will now show where the top and bottom of the virtual image are, just fill in by drawing in the image.

(sorry that was a little confusing)