Want to wake up everyone?
How can you wake up everyone on a Sunday morning, at the time YOU want? Make a horn that you can use to get them out of bed.
Get started
Step 1
Pull the balloon opening 2 centimetres over the toilet roll.
Step 2
Cut a small hole at the tip of the balloon, just big enough for the straw to go in.
Step 3
Push the straw around 1 centimetre into the hole and use the sticky tape to stick the straw onto the balloon. It should be airtight.
Step 4
In one hand, hold the toilet roll vertically in front of you.
Step 5
Use your other hand to hold the straw and pull the balloon tightly over the top of the toilet roll.
Step 6
Blow hard into the straw. Can’t hear anything? Make sure that the balloon fits tightly over the toilet roll.
Tip
Instead of a toilet roll, use a kitchen roll or the cardboard roll in kitchen foil or aluminium foil. Does the horn now make a higher or a lower sound?
What did you discover?
Sound is a vibration of the air. Blowing into the straw causes the air in the toilet roll to vibrate. That vibrating air causes your eardrums to vibrate, and your eardrums then pass on a signal to your brain so you can hear the noise.
You can hear different notes because air can vibrate at different speeds. You hear higher notes if the air is vibrating quickly, and lower notes if it is vibrating slowly. As you get older, you can hear lower notes better than higher ones. Luckily, this horn produces a low note, so it’s ideal for waking people up!
