Memorising physics equations

[Lucy in Australia]

First of all, let me state that I am slightly "challenged" in the fields of maths and physics so be kind with your answers :)

 

I am curious as to how much of the physics equations a high schooler comes across should be memorised. I have generally been of the belief that if it's something he's likely to come across more than a few times, he needs to memorise it. It has come to our attention that his peers (including those in private schools) are being told to memorise only the basic ones, and that the rest will be usually given to them in tests & exams. (He's not against all the memory work; I'm just wondering if things are changing from the days we were in high school)

[kiana]

I would recommend that you look up practice exams for the exams that he's going to be taking in future -- it varies SO much by country and exam. Just see what's included on those.

[regentrude]

I am curious as to how much of the physics equations a high schooler comes across should be memorised. I have generally been of the belief that if it's something he's likely to come across more than a few times, he needs to memorise it. It has come to our attention that his peers (including those in private schools) are being told to memorise only the basic ones, and that the rest will be usually given to them in tests & exams.

 

I do not think any physics equations should be memorized, if you use the term similar to memory work such as learning poetry or the preamble to the constitution. The student should have worked enough problems that he is familiar with them and simply remembers the most basic equations from having used them often enough. Rote memorization leads to students randomly selecting whatever equation they happen to remember, whether this is appropriate for their problem or not.

Understanding the concept and practicing problem solving will enable the student to recall the important equations.

I think any attempt to memorize the less important ones is misguided. For instance, trying to remember Bernoulli's equation is probably doomed unless the student has understood that it simply is energy conservation for a fluid, in which case he will be able to put it together and conclude what the terms have to be.

 

I teach physics at a university with a STEM focus. We provide our students with an equation sheet in every introductory course (or permit them to write their own) for the exams because we want them to focus on understanding and problem solving, not rote memorization of equations.

 

If you are concerned about specific tests, you need to look at them and see to what extent equations need to be remembered. But then I would not use memory work techniques, but plenty of problem solving using them which will eventually commit them to memory.

[Lucy in Australia]

Thank you so much for this advice! I was really hoping to hear from someone like you :) We'll definitely focus more on problem solving and leave the memory work for other subjects. I have ordered some practice exams, so we'll see what they expect. Thanks again!

[jennynd]

I think i memorize one

f=ma

all the other can be drived

[MyThreeSons]

We provide our students with an equation sheet in every introductory course (or permit them to write their own) for the exams because we want them to focus on understanding and problem solving, not rote memorization of equations.

 

This is what I do with my co-op Physics students. From high school Physics, all the way through all of my college Physics and Engineering classes, I was allowed to use "cheat sheets". Most of the time, we made our own, with some limitations sometimes imposed by the instructor; once in a while the prof would provide an equations sheet.

[creekland]

The student should have worked enough problems that he is familiar with them and simply remembers the most basic equations from having used them often enough.

 

This is how I was brought up both in high school and getting my Physics degree from Va Tech.

 

We never had to memorize anything, but we had enough of them in memory from use and knowing how they worked.

 

I will say, there was at least one class where we had to derive anything beyond F=ma when we used it, but after we had derived a formula once (on a test) we got to use it again throughout the rest of the class without having to redo it. It was a junior level class if I recall correctly. It might have been spring of sophomore year as we ended "basic" Physics. In the earlier classes we were allowed to create our own formula cards if we wanted them. In specialty classes (electricity, astro or whatever), I think we always got to use them, but my brain is kind of rusty so I might be forgetting one or two.

 

Nonetheless, it was more common than not to not need memorization of formulas.

 

* Editing to add that I just remembered I switched into Physics as a major (from Computer Science) my sophomore year. Therefore, when I remember taking my classes (which year) can easily be off. It ended up taking me 5 years to graduate with my Physics major, but that's with one semester off for health related issues. *

 

One of my pet peeves with math at my school is that there's too much emphasis on memorization and not enough on why something works (distance formula, volume formulas, etc). When something is memorized instead of known it is near impossible to choose the right equation to solve something once one is outside of class (like mixed math problems on state or college tests).

Edited March 9, 2012 by creekland

[AngieW in Texas]

I taught a physics class to prepare for the AP Physics B test last year. Many of the equation needed for the AP test were already memorized due to using them many many many times. However, some of the equations that hadn't been used in a while were forgotten when we got to the end of the course. We used the AP equation sheet as a guide for which ones to make sure were memorized.

 

This year I'm teaching chemistry. Chemistry doesn't have many formulas at all. Almost everything can be figured out from unit analysis. Unit analysis frequently works for physics too, but with physics there are often constants thrown in that have to be memorized.

[kroe1]

I never was lucky enough to get cheat sheets from a professor. But I was lucky enough to have some science professors who believed math should be taught through learning science rather than learning the math needed first.

 

Carrying this philosophy further, a formula would never need to be memorized.

 

To illustrate, suppose one has a word problem that mentions 600 miles, 3 hours, and requires an average speed. One would already know that speed is measured in miles per hour. So with our numbers mentioned, how would we get miles per hour? The miles would have to become the numerator, the "per" is the fraction bar, and the hours would have to be the denominator, right? So just put the numbers with the measurements. Six hundred miles/3 hours. Reduce your equation and one has 200 mi/hr.

 

This same process can be applied to anything in physics and chemistry without memorizing formulas. Just ask yourself where would my measurements need to be placed in an algebraic equation to come out with the answer. In other words, do the measurements algebraically and just carry the numbers along for the ride. It works every time.

 

I hope this is a little clearer than mud. After I was taught this way to look at science, I never memorized another formula again. It's not to say I didn't look at a formula and admire it's beauty. :001_smile: