In this activity you'll construct your own ruler using a piece of paper and 3 nickels/coins. Even if you have a ruler, don't use it for this activity, though feel free to check your improvised ruler's accuracy after the activity is complete. Stacked together, 3 nickels provide a reference "standard length" and will have a total thickness of 5.28 mm. If you used a different coin, you will need to search online for the standard thickness of said coin to determine your total thickness. 1. Using your 3 stacked coins, construct a ruler by making marks as closely as possible to every 5 mm. The ruler markings should cover at least 12 cm. If you think you can add even finer markings you're welcome to do so. 2. Using your ruler, record the length and width of your health card (or a card of the same size). Include uncertainty in your measurement. In this instance, a reasonable estimate of uncertainty would likely be half of the smallest increment on your tool. (E.g. if your smallest increment was ~0.5 cm. If you added finer increment markings, your uncertainty might be smaller.) 3. Neglecting the rounded edges, calculate the surface area of your health card. Include a calculation of the uncertainty in the surface area. Recall that for simple measurements, in the case of addition or subtraction: ( at Aa) + (b+ Ab) = c+Ac or ( atAa) - (b+ Ab) = c+Ac where Ac = VAa" + Ab In the case of multiplication or division: ( at Aa) (b+ Ab) = c+ Ac or atAa = c Ac b+Ab where Ac = 1/ (Ac)2 + (Ab )2 4. Calculate the percentage difference between your calculated surface area and the standard surface area. A quick google should lead you to the standard surface area. The percent difference is calculated by the following: Todiff = measured accepted x 100% Iaccepted