What is a rainbow?

Have you every looked at a rainbow and wondered our it happens. Well the Year 5 and 6 students at EHS have figured it out.

The light that we see around us looks like white light but really it is made from 7 colours.

Red
Orange
Yellow
Green
Blue
Indigo
Violet

These are all the colours of the rainbow and form part of the visible light spectrum.

To be able to see these colours the light needs to refract or change direction. This happens when light hits a CD, prism or rainbow glasses. Because each colour travels at a slightly different speed when the light refracts the colours spread out in different directions.

A raindrop acts just like a prism. The sun shines through the rain drops in the air and the light is refracted. As the light changes speed it also changes direction and all the colours spread out for us to see.

When we looked at light through these rainbow glasses we could see all the colours of the rainbow.
Mr Powell took a photo through the glasses and this is what he saw.


We also had a go at making our own water prism by shining a torch at a tilted mirror half in water. We had to persevere to get it to work but we did manage to reflect rainbows on the roof.

The primary colours of light are red, blue and green. Click on the link below to see what happens when you mix coloured lights.

Mixing Coloured Lights

EHS scientists on the front cover

It was pretty exciting this week as the new Education Gazette came out with my photo on the cover.  Here I am with a budding scientist inspecting how our bean plants are growing.

Magic Potion

Hocus Pocus and Abracadabra!

We have a magic potion that changes the colour of other liquids.
The magic potion smelled really bad. Some people thought it smelt like broccoli, cauli flower or cabbage. The people who said cabbage were right. In fact it was red cabbage juice.

Our first job was to use the dropper to carefully put some of the magic potion into each test tube. It was tricky to get the hang of using the dropper.

Next we tested 6 different liquids by squirting some into the magic potion.

Wow - Each liquid turned a different colour!

The things we tested were from right to left:
Baking Soda, Dishwashing Liquid, Lemon Juice, Washing Powder, Vinegar, Window Cleaner.

We thought this was pretty cool.
But then Miss Harrison told us that you can tell if a substance is an acid or a base by the colour it goes when you mix it with cabbage juice.

Red or Pink = Acid
Blue or Green = Base
Purple = Neutral

This was kind of hard to understand but we had fun mixing the potion anyway.

What is the best way to melt an ice cube?

This was the investigation that Year 2 classes did this week.

They decided that to make ice melt you need to heat it up.

The students had to think about where they would put ice cubes in the class to make them melt. There was also some equipment they could use.

They came up with:

• Under a light
• In the sun
• By the heater
• In someone's hands
• In some hot water
• On top of the hot water bottle
• Wrapped in a towel

First we put ice cubes into glass dishes. We had to make sure the ice was the same size so the test was fair.

Then we put each dish in a different place and patiently watched to see the ice melt.

Which one do you think melted the fastest?

In most classes the ice cube that melted the fastest was the one in someones hands or the one in the hot water.

We were surprised that the ice in someones hands melted faster than the heater. We think it was because our hands were touching the glass dish so it would heat up faster and pass the heat on to the ice. The hot water did the same because it was surrounding the dish.

More Chemical Reactions

INVISIBLE INK

To make an invisible ink you mix lemon juice with a few drops of water. Then you write on a piece of paper with a cotton bud. Leave the message to dry.

Now you are ready to read the message. Iron over the paper for a while until the message appears. The lemon juice will turn brown.

This happens because there is carbon in the lemon juice. When you heat the lemon juice with an iron the carbon starts to break down and turn brown.

You could send a secret message to your friend.

RUSTY WOOL
How do you quickly turn this steel wool rusty?

Today in science club we found out how. First you need to soak the steel wool in some vinegar. Next you squeeze out the vinegar and place the steel wool in a jar. Now poke a thermometer into the steel wool and put the lid on the jar.

We watched to see what happened to the temperature on the thermometer and notice that it went up from about 17 degrees C to 30 degrees C.
There was also some fog on the inside of the jar.

Last week we found out that if a chemical reaction gives off heat it is called and exothermic reaction. So this must be one.

We also noticed that the steel wool went rusty really quickly.

But what is reacting?

The vinegar removes any protective coating on the steel wool so the steel wool begins to rust. When something rusts it is actually a chemical reaction between the iron and the oxygen in the air. Steel wool is made of iron so it can rust. When rusting occurs heat energy is released.

Magical Mixtures

Exothermic Reactions
by Chelsea, Poppy and Andy

Today in science club we mixed water, baking soda and calcium chloride to make a chemical reaction. We put the two bases in a plastic bag and then put water in a container and mixed them together. The plastic bag filled up with air and it fizzed and foamed while it was producing gas. The plastic bag got really hot and made a sizzling sound. This is called an exothermic reaction because it produced heat. An exothermic reaction is used in heat packs and hand warmers.

Hot
by Jasmin and Caitlin

Today in science club we investigated chemical reactions. We put 1 teaspoon of baking soda and 1 teaspoon of calcium chloride in a bag then filled up half a film canister with water and put it in the plastic bag. But we didn't let it touch the powder. We sealed up the bag then shook it. The mixture foamed and fizzed and was hot in the corners and it burned my finger. It was an exothermic reaction.

Mystical Mixtures

by Billy and Jake

Today we investigated chemical reactions. We tested out 2 mixtures. One was an endothermic reaction and one was an exothermic reaction. The exothermic one was really hot and sticky and smooth. The endothermic was really cold and the bubbles vibrated in the bag.

Magical Mixture
by Eden and Harrisen

Today in science club we tested out different chemical reactions. The second magical mixture needed to have water, tartaric acid and baking soda. We put baking soda and tartaric acid into a bag and mixed them together. Next we poured water into it and all of a sudden it fizzed up and got really cold. It did this because when you put all the ingredients together it creates an endothermic reaction. An endothermic reaction absorbs heat so it feels cold.

Magic Chemicals Number 2

by Jacob and Josh

Today at science club we were investigating chemical reactions. First we had to mix baking soda and calcium chloride together. Then we poured water in the canister. We could not pur it in the bag or the experiment would be ruined. We then sealed up the bag tight other wise it might spill out. Once we sealed the bag we shook it. The water spilled out so then the chemicals reacted and it fizzed up. It fizzed up and puffed up with gas (we think it is carbon dioxide). The reaction was exothermic which means it got hot.

Magic Mixtures
by Morgan and Avilisha

Today at science club we made chemical reactions. We mixed baking soda with calcium chloride and water. They foamed and fizzed. When we felt it it was hot and sizzling. After 10 minutes it turned into a liquid. When it was hot it released a gas. The reaction was called exothermic. It felt like boiling water.

The instructions for the experiments are below.

Today I drank a solution!

And it was really yummy!!!!

Don't worry mums and dads - the solution we drank is really harmless. We were finding out about things that dissolve. When we put salt into a glass of water and stirred it around the salt seemed to disappear. But really it is still there - it has just dissolved. Dissolving means that the salt particles got so small that we couldn't see them anymore.

First we had to test lots of different things to see if they would dissolve or not. It took a lot of stirring and mixing. We had to work together and record our results.


We found out that sugar, drink powder and coffee dissolved but tea leaves, sand and flour did not.

Miss Harrison taught us 3 tricky new scientific words.
Solvent - this is the liquid part of the mixture
Solute - this is the thing that gets dissolved in the liquid
Solution - this is the mixture of the solvent and the solute.

Next we got to make a solution that we could drink - LEMONADE!

This is the recipe we used:
Lemonade

1. Squeeze the juice from 3 lemons into a bowl.
2. Add 2 cups of sugar.
3. Add 3 teaspoons of citric acid.
4. Add 1 litre of hot water.
5. Stir the mixture until the sugar has dissolved.
6. Pour some of the lemon syrup into a cup. Fill the cup with water.
7. Your lemonade is ready to drink.

Do you know which parts of the mixture are the solute and solvent? We do!

Solvent = water and lemon juice
Solute = sugar and citric acid

We even got to drink the Solution! Cheers.