Directions: Use the STEM plan on the template provided. 1. Choose your materials (cardboard, tape, cotton balls, cotton cloth, packing peanuts, bubble wrap, etc.) 2. Build your muffler, making sure to use sound-absorbing materials so your parent can't hear what you are saying. 3. Test your voice muffler- In a normal speaking voice, speak into the muffler. See if your parent can hear it. Then, repeat the same thing without the muffler. How much of the sound was blocked by the muffler? 4. Try to improve your voice muffler after that!