The Water Cycle Demonstration

We have been learning a lot about the water cycle.

Today we did our own water cycle demonstration.

We half filled a cup with water, and marked the level on the cup.

We covered this with cling film and left it on the radiator.

We hoped that some of the water would evaporate, that the water vapour would hit the cling film and would condense into water droplets, and that it would fall again as drops of water (precipitation).

We left the water on the radiator, and by home time we could see the water cycle in action.

We were very impressed!

Cloud in a bottle

We can make our own clouds in a bottle.

You need to put cold water into a bottle, then empty it out again.

Light a match and drop it into the bottle.

Squeeze the bottle.

Nothing happens.

When you stop squeezing the bottle, hey presto, you have a cloud in the bottle.

How does this work?

Clouds are formed when water droplets in the air cool and then collect on dust particles. In this demonstration, the dust particles were provided by the smoke from the match. The air inside the bottle was cooled by releasing the pressure after the bottle was squeezed.

We were delighted to be able to make our own clouds!

Diving and resurfacing jellyfish

A water investigation:

Can we get a jellyfish to sink, and then resurface?

Teacher has a jellyfish.

When we put it in a bottle of water it floats.

We think that this is because the head of the jellyfish is full of air.

Teacher wanted us to get the jellyfish to sink to the bottom and to resurface again.

What could we do?

We could shake the bottle, push the jellyfish with our fingers, roll the bottle, tilt the bottle OR  ???

We figured that if we squeeze the bottle the air in the head of the jellyfish would become a little squashed (or compressed).

This would allow some water to get into the head and be heavy enough to sink the jellyfish.

Now to make him resurface again........

Stop squeezing the bottle and the air will have space to expand again, push the water out of the head of the jellyfish.

Now the jellyfish can swim to the top again.

If you have no jellyfish, teacher showed us a way to make a diver of our own from a lid of a pen, a paper clip and an elastic band.  This works just as well as the jellyfish!

Bath Tricks

Did you know that you can empty a bottle quicker by making a whirlwind in the bottle?

That way the water stays around the outside of the bottle, while the air can rush in through the middle and push the air out quicker!

Did you know that air is all around us pushing against things?

Air pushing against a piece of card can even stop water escaping from a cup!

This is really worth trying!

Floating Fruit

We did a little experimenting with fruit today.

We found out that:

Oranges with their skins on will float,

Peeled oranges sink,

Peeled orange segments sink,

An orange segment with the skin on will float.

Orange peels float.

Bananas with their skins on will float,

Peeled bananas will float but

Banana peels sink!

Apples float!

Marla rolled in a ball (a sphere) will sink but

Marla flattened out and given curved sides will float.

In fact, it floats so well that we were able to add passengers (dried peas).

We would love to try other different types of fruit at home to investigate what floats or sinks.

Light sources and reflectors

We have been learning about light sources and reflectors.

Light sources give off light which we can see in the dark.

Reflectors do not: Reflectors only work when a light shines on them.

Reflectors don't work in the dark without a light shining on them.

We tried this out today.

We used a dark box, put an object in it, guessed whether the object is a reflector or light source, shut the lid and had a look.

 Only the torch, the glow-in-the-dark stone and the flashing pen were light sources.

The others (including the mirror) were reflectors.

Did you know that the sun is a light source but the moon is not.

The moon reflects light from the sun; it is a reflector!

Static electricity can roll a can

We can rub a balloon on a woolly jumper or on our hair.

If we do that the balloon will have an electric charge (static electricity).

Now if we bring this charged balloon beside an empty drinks can the can will move without being touched.

This is a spectacular thing to try (but works best on a dry day rather than on a wet day).

Finding acids with red cabbage

Teacher had a red cabbage in school with  her today.

It looks purple rather than red!

If you cut up a leaf and add very hot water the purple colour will start to run from the cabbage.

This red cabbage water is amazing!

It can help tell if something is an acid or an alkali (or neither).

We tried this out with some of our drinks.

We noticed the cabbage water turn pink or red with vinegar, lemon juice, orange juice, orange and pineapple juice, black current juice, and most surprisingly of all, with tea!

These are all acids and we will need to clean our teeth after drinking them.

Bread soda did not make the cabbage water turn red or pink.  Instead it made the cabbage water turn a bluey-green.

This is because bread soda is an alkali (and therefore good for cleaning!)

We wondered what would happen if we mixed an alkali with an acid.  What colour would the water turn?

We tried this and managed to get the water to turn back to the original cabbage water colour.

This means that when you mix and acid with an alkali the water becomes neutral again!

Such a fun investigation, and one that will help us mind our teeth!