If your hair is long enough, tie it back in a simple bun at the base of your neck or the back of your head. If you have difficulty with a traditional bun, you can make a loose one with nothing but an elastic ponytail holder. Tie your hair back with the ponytail holder. On the final wrap-around, do not pull your ponytail all the way through; instead, pull the hair through the elastic band just enough to create a bump or bun at the top. To keep the ends secure, wrap a second elastic band around the first. If your hair is too short to put in a bun, consider adding tight curls using hair rollers. If you don't have rollers, consider using bobby pins to create tight pin curls, instead. The main idea is simply to create tight curls that frame the face or otherwise stop above the shoulder. Loose, flowing curls would not work as well. Alternatively, you could leave the curlers in your hair. This will create a much more casual, "at home" look. Make sure that the curlers are secure, though, so that they won't accidentally fall out as the day passes. A simple trick for making hair look grayer is to dust it with a little white powder, like baby powder or flour. Less is more, though. You want the hair color to look faded, but you don't want the powder to be especially noticeable. Evenly sprinkle the powder over your head. It is best to sift it out, rather than applying it with your hands. Once it's on there, shake your hair to break up any clumps and help spread the powder throughout. You may even wish to run a comb through your hair to help spread the powder. Spray a little hairspray over the hair after applying the powder to help prevent the powder from falling out. When done, both baby powder and flour should wash out of your hair with enough water and shampoo. Baby powder might be easier to strip from your locks than flour would be. Another option is to simply buy a cheap gray or white costume wig. You can usually find an old woman's wig at any store that sells costume supplies.
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One-sentence summary -- Put long hair in a bun. Curl shorter hair. Sprinkle on some baby powder or flour. Consider investing in a wig.

You will still be growing out your back and sides, but since the hair on the top of your head is shorter, the overall process won't take as long. How short you cut the hair on the top of your head depends on the style you're going for. For example, if you want to go for a quiff, trim your hair to about 2 to 212 inches (5.1 to 6.4cm). Since you are starting with a shorter goal, this should only take about 3 to 4 months. You can stop when the sides are about 1 to 112 inches (2.5 to 3.8cm) long. This will give you enough hair to work with for the final blend. Once the sides and back are almost the same length as the top, it's time to blend them. Run a pair of trimmers along the area where the sides and back curve into the top of your hair. If you aren't sure how to do this, go to a hairdresser. Ask for a medium taper or a clean-cut taper. If you still want to keep your back and sides short, try a quiff or pixie. Both are similar, except that the pixie has more feathering. Again, how short you go depends on what your goal style is. For example, a quiff or taper may have trimmed edges along the bottom, but a pixie may have slightly longer hair. If you went to a hairdresser for the blending, then they will already have done this for you, based on your desired style. Depending on what style you chose, there are lots of ways that you can go about with this. In most cases, you will need to blow dry your hair by brushing it back and upwards. If you got a quiff, apply a volumizing mousse to your damp hair, then blow dry it upwards and back with a round brush. If you got a pixie, you can go as wild as you like. Blow dry shorter pixies like quiffs; blow dry longer pixies short. Use a little bit of styling wax or pomade to set your style.
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One-sentence summary -- Trim the hair on top of your head to your desired length. Allow the sides and back to grow until they match the top. Blend the sides and back into the top. Trim the bottom edges of your hair to complete the cut. Style the longer part of your hair, if desired.

Let's say you're measuring a stick that falls near 4.2 cm, give or take one millimeter. This means that you know the stick falls almost on 4.2 cm, but that it could actually be just a bit smaller or larger than that measurement, with the error of one millimeter. State the uncertainty like this: 4.2 cm 0.1 cm. You can also rewrite this as 4.2 cm 1 mm, since 0.1 cm = 1 mm. Measurements that involve a calculation of uncertainty are typically rounded to one or two significant digits. The most important point is that you should round your experimental measurement to the same decimal place as the uncertainty to keep your measurements consistent. If your experimental measurement is 60 cm, then your uncertainty calculation should be rounded to a whole number as well. For example, the uncertainty for this measurement can be 60 cm 2 cm, but not 60 cm 2.2 cm. If your experimental measurement is 3.4 cm, then your uncertainty calculation should be rounded to .1 cm. For example, the uncertainty for this measurement can be 3.4 cm .1 cm, but not 3.4 cm 1 cm. Let's say you're measuring the diameter of a round ball with a ruler. This is tricky because it'll be difficult to say exactly where the outer edges of the ball line up with the ruler since they are curved, not straight. Let's say the ruler can find the measurement to the nearest .1 cm -- this does not mean that you can measure the diameter to this level of precision. Study the edges of the ball and the ruler to get a sense of how reliably you can measure its diameter. In a standard ruler, the markings at .5 cm show up clearly -- but let's say you can get a little bit closer than that. If it looks like you can get about within .3 cm of an accurate measurement, then your uncertainty is .3 cm. Now, measure the diameter of the ball. Let's say you get about 7.6 cm. Just state the estimated measurement along with the uncertainty. The diameter of the ball is 7.6 cm .3 cm. Let's say you're measuring a stack of 10 CD cases that are all the same length. Let's say you want to find the measurement of the thickness of just one CD case. This measurement will be so small that your percentage of uncertainty will be a bit high. But when you measure 10 CD cases stacked together, you can just divide the result and its uncertainty by the number of CD cases to find the thickness of one CD case. Let's say that you can't get much closer than to .2 cm of measurements by using a ruler. So, your uncertainty is .2 cm. Let's say you measured that all of the CD cases stacked together are of a thickness of 22 cm. Now, just divide the measurement and uncertainty by 10, the number of CD cases. 22 cm/10 = 2.2 cm and .2 cm/10 = .02 cm. This means that the thickness of one CD case is 2.20 cm .02 cm. To increase the certainty of your measurements, whether you're measuring the length of on object or the amount of time it takes for an object to cross a certain distance, you'll be increasing your chances of getting an accurate measurement if you take several measurements. Finding the average of your multiple measurements will help you get a more accurate picture of the measurement while calculating the uncertainty.
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One-sentence summary --
State uncertainty in its proper form. Always round the experimental measurement to the same decimal place as the uncertainty. Calculate uncertainty from a single measurement. Calculate uncertainty of a single measurement of multiple objects. Take your measurements multiple times.