Gcse physics

[JC4PMPLZ]

How can physics be so hard? This is Trilogy, not even the harder one, but my daughter is struggling so much, and I cant work anything out on BBC Bitesize, What to do? Every other subject I can have a fair crack at?

Good advice from physicskate
DD found physics hard, so she practised using old exam papers, and ended up with the highest UMS marks of the three sciences she took.

What she struggled with was that so much of it is intangible theory. At least with biology and chemistry you can physically see what is going on and everything seems much more logical.

DD did double and struggled with the physics component - so dh (who did physics at Cambridge) decided to tutor her - he was utterly appalled by her lack of basic knowledge, understanding the concepts and thinking them through to answers questions was not something that had been rehearsed at school, her science teachers with staff turnover being incredibly high. Dh spent time, maybe an hour or two with her every week from Feb - May and she ended up with 8:8 in her GCSE up from 6:5 in her mocks.

Concepts are key, but a lot up to this level is taught as how to answer questions. If you can understand the concepts then there is very little to actually learn. Good luck finding the right resources to help!

So relieved to have found this post!
DD is in year 11, DS is in year 9, so we are going through the energy topic for the second time and it STILL fries my brain!
For example, what is the spring constant? Why do you only calculate 0.5? Why is the extension to the power of 2?
And then, why does GPE involve mass x GFS, rather than simply weight?

The spring constant is just a number assigned to an individual spring to indicate its relative 'stretchiness'. F = kx. So if the same force stretches twice the extension as another spring, it has a smaller spring constant (k) to indicate that it is stretched more (the extension is larger).

It makes the maths work so that you can predict how far a spring is stretched if you know the force applied and the constant. If you have a graph of different forces applied against extension, k is the slope (or the inverse of the slope depending on which way round the axes are). That's how you find k of an individual spring, generally (to ensure it hasn't passed the elastic limit).

Honestly, this is not a concept that needs to be understood at gcse, just applied by using the formula f=kx. I've never seen a question (hm maybe one at a level?) where you are required to compare spring constants.

To calculate the work done by extending a spring (which is the same as energy stored in a spring), work = f x d. Where f is the force applied and d is the distance this force causes the spring to extend. Oh wait! We also know that f = k x. So substitute this into the work equation gives you work = k x (squared). Hm so then that leaves is with the problem of the one half. And that actually relates back to the graph... work = force x extension is equal to the area under the 'curve', which makes a triangle shape on these graphs. The area of a triangle? 0.5 base x height. So that's where your 0.5 comes from. Work = 0.5 force x extension = 0.5 (kx) x = 0.5 k x(squared).

Again, this is NOT a proof you would normally see or need to 'understand' in any sense at gcse... you simply need to be able to apply the formula. I would generally only show this to a top top set, and expect maybe one or three 8/9 grade pupils to 'follow' it.

Gpe = mgh = weight height. Because don't forget work = force * distance and weight is a force!

I'm really sorry about the bold. I don't know how to undo it on the app and cvs typing it all out only for the same to happen. Hope that helps a little @Alsoplayspiccolo.

Thank you so much, physicskate, that is extremely helpful, not least because I now know I don't need to understand why, only be able to apply! I really thought I was missing something, so it's good to know just knowing and using the equations is enough.