Article: "Pump filters" may be your cheapest option in this category, but can be slow and tedious. For long trips, look into "gravity filters," which are typically a pair of bags connected by a hose. The bag with the filter is filled with water, then hung up to let the water drain through the filter into the clean bag. This is a fast, convenient option that doesn't require you to carry around a supply of disposable filters. These filters do not protect against viruses, but they are effective against bacteria. Not all wilderness areas require protection against viruses, however, especially in the US. Check your regional disease control center or a tourist information center for more information on the risks in your region. Tablets are slow but cheap, and are effective against most bacteria and viruses. Tablets come in two common types:  Iodine tablets should be left in the water for at least 30 minutes. They are sometimes sold with a companion tablet for hiding the iodine taste. Pregnant women and people with thyroid conditions should not use this method, and no one should use it as their main source of water for more than a few weeks.  Chlorine dioxide tablets normally have a 30 minute wait time. Unlike iodine, they are effective in areas contaminated by the bacterium Cryptosporidium – but only if you wait 4 hours before drinking. Ultraviolet light lamps can kill bacteria and viruses, but only if the water is clear and the light is applied for long enough. Different UV lamps or light pens have different intensities, so follow the manufacturer's instructions. This is an extremely effective method of killing pathogens, as long as you let the water boil for at least one minute. It may not be convenient to boil water several times a day, but be aware that you won't need additional filtration if you're already boiling water for your evening meal or morning coffee. At high elevations, boil the water for at least three minutes, since the water will boil at a lower temperature in the thin air. The high temperature, not the boiling action itself, is responsible for killing bacteria and viruses. Plastic bottles are only designed to be filled an used once, since the plastic can break down over time, adding potentially harmful chemicals to the water and even harboring bacteria. Even aluminum bottles often have an inner plastic coating, and are not dishwasher safe, making them difficult to clean. If you're lucky enough to find a mountain spring bubbling from the rocks, it's usually safe to drink directly from it – but this does not apply even a couple feet (0.6 m) away. This is not a foolproof rule, and may be dangerous in agricultural regions, areas with historic mining, or lower-elevation areas near population centers.
Question: What is a summary of what this article is about?
Consider a physical filter. Learn about chemical disinfection. Try UV light treatment. Boil water. Use stainless steel water bottles. Drink straight from the spring source.

Problem: Article: Include all the people you wish to invite to your party. The number of people you invite will depend on the size of the room and on how many guests you can have over. Since a pajama party can range in size from a few close friends to a larger number of people that you know, it’s important to have an idea of how many people you actually want and can have at the party before sending out invitations. You can buy pre-made pajama party invitations at retailers like Zazzle or you can make your own. You can also create a Facebook event for the party. The invitation should include the following information:  Date of the party. Consider hosting the party on a Friday or Saturday night. That way, you and your friends will be able to recover and catch up on sleep the next day.  Time the party will start and end. Sleepover pajama parties usually start no earlier than 5 p.m. and go until 10 a.m. If your pajama party is not actually a sleepover and is instead just a party in your PJs, specify this and give an idea of when the party will end so guests can plan accordingly.  The address for the event. A date guests should RSVP by. Your phone number and/or email. What to bring. This could range from a swimsuit to a sleeping bag to pillows. The theme of the party, if any. If you invite people too close to the day of the party, you run the risk of there being overlapping events or conflicts. Avoid this by letting your friends know about the party at least 2 weeks ahead of time. Traditional slumber parties take place indoors, usually in the living room or the bedroom of the hostess. However, if you want to take your party to the next level, consider hosting an outdoors pajama party using the backyard as the party area. You can also set up tents as your shelter.
Summary: Make a guest list. Write the invitations. Send timely invitations. Set the location.

Being nice is a great way to make a boy feel more comfortable around you. Keep your compliments genuine and specific, and say them with a smile so he knows that you aren’t teasing him. Sometimes, it’s better to give compliments when you’re hanging out alone, to keep other people from making fun.  For example, if you’re both into sports, you can say something like “I like your Lebron James jersey, did you watch the game last night?” If you’re working on a school project together, let him know that you admire his intelligence by saying something like “That’s a great idea, I would’ve never thought of that!” Focus on asking questions that require an explanation, not just a “yes” or a “no.” If you know you have a common interest, like music or sports, ask him questions to lead him into a conversation. Let him do the talking while you listen and throw in some comments here and there.  This is the best way to get to know a guy to see if you could actually like him beyond just a crush. Letting him talk will show him that you’re interested in getting to know him better and that you’re a good listener. Think about how you act around your girlfriends and how easily you can talk to them. Try to act the same way around the boy that you like by talking about things you both are interested in, like music, sports, or movies. Share your opinions and thoughts freely so he can get to know the real you. If a guy seems less interested after you start talking to him, don’t worry about it. That just means that he’s not a good fit for you. Body language and touching are a great way to communicate to a guy that you like him without outwardly saying something. Sit close to him so that your knees are touching, and reach out to touch his arm or leg when he says something funny. This can signal to a guy that you’re interested in him as more than just a friend. Avoid doing anything too overt, like grabbing his hand out of nowhere. This can scare him or make him think that you have the wrong impression about your relationship. Smaller gestures are better for figuring out how he feels. It might seem simple, but guys are surprised when girls are confident enough to show interest in a public way, like on social media. Even a quick text to let him know that you saw something that made you think of him can ensure that you’re on his mind, too!  Sending a text can even start a whole conversation that can bring you closer together and give you something to talk about in person. Keep your texts light and flirty until you’re able to hang out with him and see how he’s feeling. Be careful not to bombard him with notifications by sending multiple text messages in a row or liking more than 2 posts at a time. When responding to texts, send 1-2 messages as your response and then wait for him to answer. Boys can sometimes act different when they’re alone with you. Ask him to partner with you for a project or even just talk to him between classes. This will give you time to see how he feels about you when no one is around, and gives him the opportunity to ask you out. Most guys won’t ask out a girl in front their friends because they’ll be embarrassed if you say no in front of everyone. Alone time gives him a chance to talk to you without all of the pressure.
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Give him a compliment on something that you like about him. Ask him questions about his hobbies and interests. Let your personality shine in your conversations. Make an excuse to touch his arm or hand. Send him a text or like his posts on Instagram and Twitter. Make time to be alone together.