Article: Talk to the other TED event attendees on a casual basis during time away from the event stage. This will let you get to know how well your actual audience matches with your imagined audience and also provide some familiar faces in the crowd when you go on stage. Although you may have revised the content and presentation of your talk a number of times based on the feedback you've gotten from rehearsing it, once you have a style you're comfortable with, stick with it. Don't make any last-minute changes to your delivery. While you've spent time creating and refining your message, it's not for the sake of the information but about sharing it and your enthusiasm for it with your audience.
Question: What is a summary of what this article is about?
Get to know the people you'll be speaking to before you give your talk. Stick to your planned delivery style. Remember why you're giving a TED talk.
Article: The density of a substance is equal to its mass divided by its volume. You can measure the mass on a scale and record the volume of the liquid used. Use the equation "m / v = D" where m is mass in grams or kilograms, v is volume in milliliters or liters, and D is density. For example, if you had a sample that was 8 grams and 9 milliliters, your equation would be: "8.00 g / 9.00 mL = 0.89 g/mL." Weigh an empty container first and record its weight. Next, fill your container with the desired liquid and weigh it again. The mass of your liquid is equal to the second measurement minus the first. For instance, if the filled container weighed 2.00 lbs and the empty container weighed 0.75 lbs, the equation would be: "2.00 - 0.75 = 1.25" and the liquid would weigh 1.25 lbs. Between -10 degrees Celsius and +30 degrees Celsius, the density of water can be rounded to 1.00 (assuming 3 significant figures). If you are using liquids that do not fall in that temperature range, you can measure the mass and the volume of your water and calculate the density. Alternatively, you can often find charts with the density of water at different temperatures. It's important to find the density of water that is the same temperature as the liquid in order to get accurate measurements. Substances expand when they are heated and contract when they are cooled. Since density is a measure of how much mass is in a given volume, the measurement is changed by the expansion and contraction due to temperature. If you want to get accurate specific gravity calculations, it is necessary that the liquid you are measuring and the water that you are using as a comparison are both at the same temperature. The units will cancel out in this equation, leaving you with a unitless quantity. That number is the specific gravity (or relative density) of your liquid. The ratio used will be "Dl / Dwater" where Dl is the density of your liquid and Dwater is the density of your water. For example, if you were to take the density of acetone (0.787 g/mL @ 25 degrees C) and divide it by the density of water (1.00 g/mL @ 25 degrees C), you would get 0.787g/mL/1.00g/mL=0.787{\displaystyle 0.787g/mL/1.00g/mL=0.787}.
Question: What is a summary of what this article is about?
Obtain the density for the liquid in question. Obtain the density of an identical volume of water. Keep your liquids the same temperature. Calculate the ratio of the liquid's density to the density of water.
Article: Making the perfect snowball will require the perfect snow. Know that temperature, humidity, and pressure will determine if it is light and fluffy or wet and heavy. The best temperature is just below freezing, around 32 degrees Fahrenheit or 0 degrees Celsius. Wet snow will pack best. Dry snow will pack poorly. Make your snowballs roughly the size of a baseball. Cup your hands, place them in the snow, and bring them towards each other. Squeeze the snow together to start compacting the snow into a snowball. Don't make your snowballs too large, they can be hard to throw accurately. Wear gloves instead of mittens to allow you to more accurately form the snowball. Try using your bare hands, allowing your body heat to help form the snowball. Add a small amount of water to your snowball now if the snow isn't the right consistency for packing. Be careful with the amount of water you add. Strive for the right uniformity in your snow, not too wet and not too dry. Using too much water will melt your snowball. Add only enough water to help hold it together. Do not turn your snowball into an "ice ball"! Scoop up another handful of snow. Pack this snow onto your original core snowball. Make sure your layers are sticking together. Gently apply pressure as you work your hands around the snowball. Add just enough to reinforce the snowball, don't make it too large. Don't pack with too much pressure as this might break the snowball. Keep adding layers until your snowball feels like a good size and consistency for you. Smooth any rough edges or bumps out of your snowball by brushing them off with your fingers. Increase speed and accuracy when thrown by making the smoothest finish you can on your snowball. If the snowball is too big, brush some snow off or pack it tighter. Don't worry if it's not perfect! If you have time, let your snowball sit for a few minutes to allow for maximum solidity. Locate the best target you might have in sight. Aim carefully and pull your arm back, readying the throw. Wait for the right moment and send your snowball flying. Throw only at people who are playing with you! Never throw at bystanders or animals. Practice by throwing at a snowman you have built. Stay calm and aim well, even during an intense snowball fight.
Question: What is a summary of what this article is about?
Find the best snow you can. Form the core of your snowball. Reinforce your snowball. Add another layer of snow to your core. Refine your snowball. Find your target!