School children can learn about the bacteria that are living all around them by collecting samples and growing bacteria in petri dishes. Start by mixing an agar mixture with water and pouring it into petri dishes so that they are around three-quarters full. Allow the agar to congeal completely. Wet the ends of cotton swabs, and use them to wipe different areas around your house or classroom, such as a sink, floor or mouth. Use a different swab for each location. Wipe the swab around the agar in the petri dish. Use one dish per swab. Place the petri dish cover onto the petri dish, and allow it to sit on a counter top for around one week. Each petri dish will display different bacteria growth.
School-aged students usually enjoy making loud noises, and making balloon speakers will demonstrate to students that sound can be amplified when it bounces off of another surface. Inflate two large balloons, and tie the ends to seal them. Take turns placing the balloons onto each student's ears to allow them to hear the difference in amplification when the balloons are present.
An easy and effective experiment for school-aged students is to demonstrate the capillary action of paper. You can use this experiment to teach children that capillary action is seen in the human body, in plants and in the natural world. Twist a sheet of paper towel up until it becomes a tightly rolled rope. Fill a glass halfway full of water, and add in three drops of food coloring. Place the paper towel rope into the water. The colored water will move through the paper towel by capillary action, causing the dry end of the paper towel to become wet and colored.