Good help shouldn't be gatekept. These are the resources we actually recommend to our university students between sessions — what each one is good for, and the catches to know before you rely on it.
What we use it for: calculus homework from Calc 1 through Calc 3. Clear notes, practice problems, and solutions that explain each step. It also has algebra and trig review, differential equations, and tips on how to study math.
What we use it for: full, free university textbooks. University Physics Vol. 1–3 covers mechanics, waves, optics, thermodynamics, E&M and modern physics (there's also a combined edition). The Chemistry and Biology books have great examples and lots of practice questions.
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The physics books only give answers to even-numbered questions, and some sections assume you know vectors and calculus.
What we use it for: every chemistry topic, often covered in several articles by different authors. If one explanation doesn't click, another route usually will. Thorough worked examples, guides on how to approach each type of question, and practice problems.
What we use it for: in-depth coverage of every Orgo 1 and 2 topic, with every mechanism drawn out and the content organized to take you through it step by step.
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There are lots of practice problems, but the answers need a paid membership.
What we use it for: don't let the name fool you. His physics playlist covers kinematics, dynamics, energy, gases and more, and his orgo videos walk through mechanisms with clear drawings and full exam reviews.
What we use it for: 3D models of molecules and whole reactions you can rotate. Seeing structures in 3D makes enantiomers, isomers and conformations click, and helps with basic shapes like tetrahedral and trigonal planar.
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Not every structure is on there. Search the molecule or reaction name and see what comes up.
What we use it for: videos on most sections of biology, including cell structure, cell division, proteins and evolution. Great for walking through a topic before you read the chapter.
More coming soon: high school and IB resources are on the way. Follow @valencetutors to catch them first.
Reading a worked solution feels like understanding. Attempting it first shows you what you actually know.
Was it the concept, the setup, or a careless slip? Each one needs a different fix.
No notes this time. If you can solve it cold, it's yours for the exam.