Your child can extract the flakes of iron she eats in a bowl of breakfast cereal in this experiment. A neodymium magnet, purchased from a hardware store, is 10 times stronger than a typical magnet and produces more dramatic results. Pour about 1 cup of Total into a zip lock bag. Add 1 cup of warm water. The cereal will need one hour to dissolve in the warm water. Your child can squish the mixture with her hands. When the consistency is similar to soup, run the magnet along the side of the bag and watch small black flakes gather along the edge of the bag near the magnet. These black flakes we eat are made of the same iron that holds a house together.
An advanced second grade student can begin to understand the consequences of actions even though they may have little to no direct effect on his own life. Your child can begin to comprehend that an oil spill has major implications for a regional ecosystem. Shape a boat out of aluminum foil. Fill a glass casserole with water. Your child can float the small boat on the water. Pour 1/4-cup of vegetable oil into the boat. Tip the boat and watch as the oil, which is less dense than water, begins to spread across the surface of the water. Your child can discuss with you what animals would be impacted by this seeping oil. He can experiment with cotton balls, paper towels, nylons and other materials in an attempt to clean the oil from the water's surface.
Many children have experience with blowing bubbles and watching them as they float slowly to the ground and pop. Demonstrate to your second grader the impact of air density with this science experiment. Spread 1/4-cup baking soda across the bottom of a glass casserole dish. Add 1 cup of vinegar. While your child is watching the bubbles fizz in the dish, explain that what the eye cannot see is the invisible layer of carbon dioxide building up. Because carbon dioxide is denser than the air in the atmosphere, it will remain contained in the bottom of the dish if undisturbed. Slowly blow a bubble, using a bubble solution made out of water and dish soap, above the casserole dish and watch as it floats down onto the layer of carbon dioxide air. It will not be able to penetrate the dense carbon dioxide air and will seemingly levitate in mid-air above the casserole dish.
Air pressure is all around us, and people deal with its impact all the time often without knowing it. Demonstrate for your child the strength of this invisible phenomenon. Set one hard-boiled egg on a glass jar with a mouth about 1-1/2 inches wide. When asked, your child will not be able to squeeze the egg into the jar. Remove the egg and any bits that may have fallen into the jar in the attempt. Place a rolled up piece of paper towel into the jar. Light one corner with a match. As the paper is burning, the fire is removing the oxygen in the jar and lowering the air pressure. Place the egg on the mouth of the jar. The air pressure outside the jar becomes greater than the air pressure on the inside. Right before her eyes, your child will watch as air pressure pushes the egg inside the jar.