Science for Kids: Water bottle fountain

Jul 25, 2012

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This experiment allows children to see that air takes up room and is always present even though we can't see it.

Ages: 2 -12+ 
(see the bottom on how to simplify or extend to meet the needs of your child)

  • Empty water bottle 
  • balloon
  • straw 
  • blu-tac (or similar)
  • tray for catching the water (optional. You could always do it outside, in a bath, or near a sink)

Begin by blowing up a balloon and asking your child "What is in the balloon?"

Let the balloon go and talk about what happens.

Next: Take the empty water bottle and ask your child "What is in the bottle?"

Blow up the balloon again and place the mouth of the balloon over the empty bottle without letting too much air escape.

Ask your child, "Why isn't the balloon going down?"

Investigating to see if she can see why the balloon is not going down.

Explain that the balloon is not going down because the bottle is full of air so the air inside the balloon has no where to escape.

Now, to make the water bottle fountain

Carefully, with a pen, poke a hole in the empty bottle just big enough for a straw to poke through and seal with blue tac. (This is the hardest part of the activity and is best done by an adult. 

If the bottle is wet, the blu-tac will be hard to stick)

Ask your child, "What do you think will happen if we pour water in?"

Pour water into the bottle over the level of the hole.

(NOTE: Make sure that your straw is pointing up, (unlike what's pictured here) and that you fill the water so that it's level with the very top of the straw.. this is because water will level itself out so anything above the top of the straw will probably come out)

Plug any leaks that you have by squishing down the blu-tac. 
At this point with the water at the same level as the top of the straw, it will not come out.
This, you can see was quite surprising for her :)

Blow up the balloon, hold it closed and put the mouth over the top of the bottle.
Let go, and wheeeeeeeeeeeeeeeee! a fabulous fountain!

She loved that you could see the balloon go down as the water streamed out the straw

She understood that "the air in the balloon pushed down on the water and forced it up the straw."

But she especially loved it when the balloon ran out of air and the water fountain did some funny last spits before stopping!

Handy Tips:

- Simplify this activity by not questioning your child as much and just letting them experience the joy of the water spouting out the straw as the balloon. 

Do the very start of the activity with the air and let it rush out on their fingers or toes and then ask them what's in the balloon or tell them that what was in the balloon was air. 

When you show them the water fountain experiment, tell them that the air in the balloon is pushing down on the water like it did on their toes, so the water goes up the straw.

- Extend this activity by having your child make a prediction about what they think is going to happen. 

You could even extend as far as having them write a report on it or write it up properly with a hypothesis etc.

- Allow your child to manipulate or be in control of as many of the steps as they are capable of. 

- Talk with your child about what they are doing. This will help them understand the physical and mental processes they are going through as well as giving them the vocabulary to describe it.

- Use new language and descriptive words like, "invisible" and "pressure." This will help with their language development.

- Listen to your child talk as they go through their experiences. 

This will help you determine where they are at with their learning, knowledge and understanding and help you to develop the activity (or future activities) to their level and interests.

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Happy playing,
Debs :)

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