Phew! Blowing up balloons can be really hard work. Why not make things a little easier using some simple science?
What you will need:
Some water or soda bottles (two large ones and two smaller ones)
Bicarbonate of soda
Hot water (from the tap is fine)
Two containers for the lemon juice (glasses will do)
A lemon squeezer (optional)
Two large bowls
▲ Take one of the big bottles and carefully place a balloon over the mouth of the bottle. Make sure that no air can escape.
▲ Get another balloon. Stretch it, then place it over the mouth of the other big bottle.
▲ Put both of these bottles in the freezer. You should leave them there for about an hour.
▲ Take the lemon and slice it in half. Squeeze each half of the lemon into a different container so that you have equal amounts of lemon juice in each container.
▲ In the two smaller bottles, place three to four teaspoons of bicarbonate of soda in each bottle.
▲ Take out two more balloons. Stretch one out. This is the tricky part. You want to get the lemon juice into the bottles and then very quickly seal them with a balloon over the mouth of each bottle.
▲ Compare the two balloons. Which one worked best? Why do you think that might be?
▲ When the hour is nearly up, get the two bowls and half fill them with hot water. Be very careful that the water doesn't splash you. It's probably best if you ask a grown up to help you.
▲ Take the two big bottles out of the freezer. Do they look the same?
▲ Place the bottles in the bowls of hot water. Hold them there and wait to see what happens. Which balloon worked best? Why do you think that might be? (catherine Thomas, staff writer)
For next Sunday's experiment you will need the following special items: Borax, cornstarch and child-safe glue.