As a parent or guardian, you are usually footing the bill for supplies and using your time to assist your child with a project, so you must be aware of what that entails before you begin. Seeing the project through is important to the child's confidence, his grade and the trust in your relationship. Choose projects where the supplies can be bought locally, or ordered if time permits. Try to avoid projects that cause you to do most of the work because it is too complicated or dangerous for your child's age group.
This project displays chemical properties and shows the effects that these properties can produce. You need vermicelli noodles (about 10), baking soda, vinegar, a glass mixing bowl and water. Put water in the bowl and add 3 tsp. of baking soda, stirring it until it dissolves, and put the vermicelli noodles in the bowl broken into 2 inch pieces. Add 3 to 4 tbsp. of vinegar. In a few minutes, your noodles should start dancing. If they don't, add more vinegar and baking soda.
The explanation is that the noodles are denser than the water that they are sitting in and so they sink, but as the baking soda and the vinegar react, they produce gas bubbles (carbon dioxide), which are less dense than water, that float to the surface, taking the noodles with them. When the bubble reaches the surface, it pops and the noodle falls back to the bottom. You can also use raisins or mothballs instead of noodles.
This project demonstrates how adding a solute to a solvent can lower the freezing point which is a colligative property in chemistry. You need one small and one large Ziploc bag, milk, whipping cream, sugar, vanilla flavoring, rock salt, ice, thermometer, measuring cup, Styrofoam cups and plastic spoons. Combine 1/4 cup of sugar, 1/2 cup of milk, 1/2 cup of whipping cream and 1/4 tsp. of vanilla flavoring into the small Ziploc bag and mix it well. Put 2 cups of ice into the large Ziploc bag and, with a thermometer, take note of the temperature inside the bag. Add anywhere from 1/2 to 3/4 cups of rock salt to the large bag and place the small bag inside the large one. Seal it. Rock the large bag back and forth gently, but be sure to hold the top of the bag; it will get so cold that it can cause damage to the tissue in your hands. After about 10 to 15 minutes, the contents of the small bag will solidify and become ice cream. Note the new temperature of the ice in the large bag. Eat and enjoy.
When the salt is added to the water (ice) a solution is formed which results in a lower freezing point. "The greater the concentration of solute, the lower the freezing point of the solvent." If you look at the difference in the temperature of just the ice and temperature after the salt was added, you will see how far the freezing point dropped.