Have you ever wondered why some things disappear when they are put in water but other things do not? For example, you may have seen that salt disappears, or dissolves, when it is mixed in a glass of water. But when you throw a rock in a stream it will not usually dissolve, and instead it will just sink to the bottom. And then there are some things that do not act like the salt or the rock. These are called colloids. If you have made Oobleck out of cornstarch and water, then you have seen…
A solution consists of a solute dissolved in a solvent. A solution is saturated when no additional solute will dissolve in it. Can a saturated solution of sodium chloride dissolve any Epsom salts? Can a saturated solution of Epsom salts dissolve any sodium chloride? How does solubility vary with temperature? How does solubility vary with the surface area of the solute? Design experiments to find out! (Gardner, 1999, 16-17, Stretton, 2004)
If you stare at a waterfall, or look at passing scenery from the window of a moving train, you will have a strange sensation when you turn your gaze to something stationary. You can investigate these types of motion after-effects
with simple equipment described by the .
How long does it take to induce the effect? How long does the effect last? Can the after-effect be canceled by viewing motion in the opposite direction? (Staff, date unknown)
A solution consists of a solute dissolved in a solvent. A solution is saturated when no additional solute will dissolve in it. You'll need a gram balance, a 100 ml graduated cylinder, three beakers or glass jars, three saucers, water, 50 g non-iodized salt (NaCl), 50 g Epsom salts (MgSO4) and 250 g sugar (sucrose). Method 1: Measure 100 ml water and pour into an empty beaker or jar. Weigh out the suggested amount of the solute to be tested. Add a small amount of…
Yeast contains an enzyme, called catalase, that acts as a catalyst for the reaction that breaks down hydrogen peroxide into oxygen and water (2H2O22H2O + O2). Safety note: oxygen is a highly reactive gas, adult supervision recommended for this project. For your background research, be sure that you understand substrate, catalyst, reaction rate, catalase, enzyme saturation and protein denaturation. Use a solution of 3% H2O2 for the substrate. Construct an apparatus that allows you to collect…
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Adult supervision is recommended for this project.
You can measure the viscosity of a fluid using a glass tube and a marble with slightly smaller diameter than the tube. Seal one end of the tube. Fill the tube with the fluid to be tested. Drop the marble into to the tube and measure the time it takes to fall a fixed distance. Repeat the measurement several times, and use the average value. How does viscosity change with the amount of sugar dissolved in water? How does viscosity change with temperature?
Use a video camera to analyze the angle of lift with different clubs. Measure the distance the ball travels. Be sure to conduct a sufficient number of trials with each club so that your results are consistent. This can also be a great way to work on your swing! (Idea from Goodstein, 1999, 83-85.)
The rebound rating is the ratio of the height the ball bounces to, divided by the height the ball was dropped from. Use the rebound rating to measure the bounciness of new tennis balls vs. balls that have been used for 10, 20, 50, and 100 games. Another idea to explore: does it matter what type of court the ball is used on? (See: Goodstein, 1999, 63-64.)
You probably know that you can use iron filings to reveal the magnetic field produced by a strong magnet. If you sandwich the iron filings between pieces of waxed paper, you can make a permanent record of your magnetic experiments (Gardner, 2004, 66). Cover the wax paper sandwich with a layer of brown paper (from a roll, or cut open a paper shopping bag), and then (with an adult's help) use a hot, dry iron to seal the waxed paper together. You will have to experiment a little with your iron…
Block off one-third of a soccer net with a cone, 5-gallon bucket or some other suitable object. Shoot into the smaller side from a set distance, but systematically varying the angle to the goal line. Take enough shots at each angle to get a reliable sample. How does success vary with angle? For a basic project: How do you think your success rate will vary with angle? Draw a conclusion from your experimental results. A bar graph showing success rate at different angles can help to…
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