Almost every food you consume has calories. Sixth-grade students can comprehend the ideas of food calories and learn to count them through a simple lab project. The food industry learns how many calories are in food through heat. The hotter the food burns, the more calories it has. Take a small piece of food like a marshmallow and set it on a clay square. Set the food and clay under a metal soda can filled with 10 grams of water. Measure the Celsius temperature of the water before the experiment starts and then light the marshmallow on fire. Let it burn all the way down and measure the temperature of the water again. Multiply 10 grams by the temperature increase in water by degrees to get the number of calories in the marshmallow.
In chemistry, you learn about the pH scale and that most liquids are either an acid or a base. You can teach your sixth-graders the properties of these liquids and run a small project to determine which liquids are acids or bases. Fill several small beakers with everyday liquids such as lemon juice, coffee and ammonia. Avoid water because it is neutral, so will not work for the experiment. Dip a piece of blue pH paper into each beaker. If the paper turns red, the substance is acidic. If it stays blue, the substance is a base. Let the children try dipping the pH paper into the beakers to test for themselves.
Sixth-grade students are in the phase of learning where they can understand information about molecules. Polymer chains are ropes of molecules that make up objects. A project that involves piercing a balloon without popping it can help children understand how polymer chains work. Inflate a balloon and have your students pierce it with oiled-up bamboo skewers (put goggles on everyone to protect their eyes). Start piercing it through the top of the balloon and down through the bottom with slow, twisting motions. Retract the skewer and the balloon will start deflating slowly. Explain to your class that when you inserted the skewer into the balloon slowly, it gave the polymers time to stretch around the skewer without breaking the seal. This prevented it from popping as it would with a quick needle jab.
Your sixth-grade students may enjoy a lab project that clearly shows how two substances can mix, react and create a completely new substance. For example, you can show them how heat and sugar work to form caramel. Place a saucepan on a Bunsen burner. Fill the saucepan with regular granulated sugar. Stir the mixture until it becomes a rich brown liquid and remove it from the heat. Allow it to solidify and share the finished caramel with your students so they can witness the results firsthand.