To make a single potato battery you will need a potato, a galvanized nail, a copper coin, two alligator clip leads with clips on both ends, and a voltmeter. Galvanized nails are standard nails that have a zinc coating. They can be purchased at any hardware or home improvement store. Use a fresh potato as the experiment depends upon the juices inside the potato.
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One-sentence summary -- Gather the necessary materials.

In order to change your DNS settings, your computer must be connected to the Internet. Click the Apple logo in the top-left corner of the screen. A drop-down menu will appear. It's near the top of the drop-down menu. This globe-shaped icon is in the System Preferences window. On the left side of the window, click the Wi-Fi connection to which your Mac is currently connected. If you're using Ethernet, click Ethernet here instead. It's in the lower-right side of the window. Doing so opens a pop-up window. You'll find this option at the top of the pop-up window. It's in the lower-left side of the window. Doing so creates a text field in the "DNS Servers" column. Type in the address for a primary DNS server. Both Google and OpenDNS have free servers that you can use here: Google Enter 8.8.8.8 here. OpenDNS Enter 208.67.222.222 here. Click + again, then enter one of the following addresses: Google Enter 8.8.4.4 here. OpenDNS Enter 208.67.220.220 here. It's at the bottom of the window. This will save your settings and close the "Advanced" pop-up window. You'll find this option at the bottom of the window. Your settings will be applied to your Internet connection from now on. . You can do this by typing sudo killall -HUP mDNSResponder;say DNS cache has been flushed into Terminal and pressing Enter. Flushing the DNS cache will help resolve any website loading errors you might run into when you next open your browser. Click the Apple menu {"smallUrl":"https:\/\/www.wikihow.com\/images\/f\/ff\/Macapple1.png","bigUrl":"\/images\/thumb\/f\/ff\/Macapple1.png\/29px-Macapple1.png","smallWidth":460,"smallHeight":476,"bigWidth":"29","bigHeight":"30","licensing":"<div class="mw-parser-output"><p>I edited this screenshot of a Mac icon.
<\/p><p>License: <a rel="nofollow" class="external text" href="http:\/\/en.wikipedia.org\/wiki\/Fair_use">Fair Use<\/a><br>
<\/p><\/div>"}, click Restart..., and click Restart when prompted. Your new DNS settings will be applied upon opening your browser when your computer finishes restarting. You may notice some initial slow-down when visiting some sites; this is because the DNS library has to repopulate via the new DNS addresses.
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One-sentence summary -- Make sure that you're connected to the Internet. Open the Apple menu . Click System Preferences. Click Network. Select your Internet connection. Click Advanced. Click the DNS tab. Click +. Enter the primary DNS address. Enter the alternate DNS address. Click OK. Click Apply. Flush your Mac's DNS cache Restart your Mac.

Many people recommend using dark glass containers because the dark glass helps protect your perfume from light, which can shorten its lifespan. You'll also want to make sure your glass containers haven't previously contained any food items, as any residual scents will transfer to your perfume. The exception to this would be if you actually wanted to use the scent of what was in the glass container before. (Warning: peanut-butter-banana-chocolate perfume might taste better than it smells!) A carrier oil is what carries the scents in a particular fragrance on to your skin. These are generally unscented, and are used to dilute concentrated oils and aromatics that can otherwise irritate your skin. Your carrier oil can really be anything. You can even use olive oil if you don't mind the scent. One popular perfumer simmers rose petals in virgin olive oil, then combines it all with vitamin E oil to stabilize it. A common choice amongst many DIY perfumers is a high-quality, 80- to 100-proof (40% to 50% alc/vol) vodka. Other DIY perfumers favour 190-proof (80% alc/vol) alcohol. Popular choices for 190-proof alcohol include organic neutral grape alcohol and the much cheaper Everclear, which is a grain spirit. Your perfume can be made out of a wide variety of ingredients. Common aromatics for perfumes include essential oils, flower petals, leaves, and herbs. The method for making perfume will vary slightly depending on your materials. Two common aromatics used for perfume are plant materials (flowers, leaves, and herbs) and essential oils; the methods vary for each of these.
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One-sentence summary -- Buy dark glass containers. Buy a carrier oil. Buy the strongest alcohol you can find. Select your scents. Decide on a method.

In the unlikely event that you have a Sony PSP, the steps are mostly the same, except, after connecting the cable from the PSP to the computer (and powering on the PSP) but before opening the device in Windows Explorer, you have to set the PSP to USB Connection mode. On the PSP, arrow left to Settings, arrow up to "USB Connection" and press X. Now the PSP is in USB Connection mode. Windows should mount the device as a removable disk, and you will be able to browse the folders stored on your memory stick.
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One-sentence summary --
Use the same steps as described above.