When to convert units

[Jasmine Reblando 3A]

Hi all.

I often get disorganized when solving problems with conversions and I was wondering when do I convert the units in order to keep my work the most organized? Do i immediately convert all the units to match at the very beginning, convert as I go, or leave it all until the end? I find myself losing my place a lot since I try to convert everything at the beginning to have matching units.

[zackdouchy]

It's not so important when you convert the units. Just make sure that when you are plugging in quantities into certain equations that you are using the proper SI units. For example, mass should always be in kilograms, energy in joules, and volume in liters.

[Joana Fang 1K]

Yeah, as the person before me said, it's less important when, but just making you use the proper units. From what I have seen, it varies problem-to-problem for when I convert.

For example, let's say I need to find wavelength in nanometers. If I use the equation c=λν, c is in meters per second, so my λ would come out in meters. Therefore, I have to convert to nanometers afterward for the correct answer.

For another problem, if I have to use DeBroglie's Equation λ = h/(mv), and the problem gives me mass in grams, I would first convert mass to kilograms before solving (due to the units in J being kg*m^2*s^-2).

My advice would be to practice solving problems while being very aware of the units in given constants and formulas to get used to when to convert. This will help you understand when units cancel out to get you to a correct answer with correct units.

[Teresa Dinh 3L]

Hi.

I don't think it matters when you convert it, as long as you do it, but for me personally I just convert it first. Remember that when we are calculating problems that involve wavelength and energy, the SI units are J, m, and kg, while for percentage yield or empirical formulas/etc. we are in grams.

[Madison Kiggins 1E]

Hi, like those before me have said, when you do it is less important than making sure you do it at some point. For me personally, I like to look at the units of my constants and make sure the numbers I am plugging in will allow things to cancel out. Then, if the problem asks for units that require a conversion, such as meters to nanometers, I will do that at the end.

[Narin Maisha 2H]

I would say that the best way to be able to keep track of all the units would be to convert them all in the beginning. Then you won't have to confuse yourself by having to convert them later or check and try to follow which ones you've already converted versus those that you still need to convert.

[405532435]

It is important to remember the uniform units in each scenario. For example, the main ones that are used are meters, grams, and Joules.