How does a whale float?

This is the question that Miss Harrison posed.

We then did some investigating about floating and sinking to find out if we could use our science knowledge to answer the question.

First we tested different objects to see if they would float or sink. We had to think about things that might help them float or sink and record our ideas.




















Next we found out that if you change the shape of an object you can make it float. When we put the blob of plasticine in the water it sunk straight to the bottom. So we changed its shape to see if it would float. Our investigations showed us that a boat shape would float.

Stacking Colours - Water density

Last week the Year 3 and 4 classes were learning about salt water. What did they find out?

• Salt water is denser than fresh water.
  
• The more salt in water the denser the water is.
  
• Salty water sinks to the bottom and less salty water or fresh water floats on top.

The students were given 4 different colours of water and they had to work out which colours floated on top of each other. They recorded their investigations and then used this information to work out how to float 4 colours on top of each other.

Yellow had the most salt in it so it sank to the bottom. Blue had the least salt in it so it floated to the top.

"I am thinking quite hard about this"

Make sure you record accurately.

We did it!

(Thanks to www.sciencepostcards.com for the lesson idea)

Science is alive and well at EHS

Walking into each classroom at EHS shows that lots of science teaching and learning is taking place. Look at these photos that I took.

The NIWA Invertebrate Collection

Last week 2 groups of children were chosen to visit the marine invertebrate collection at NIWA in Wellington. The collection has specimens from many different groups (phyla) that live in the ocean including...
The specimens are kept in jars and preserved in alcohol so they don't go rotten and smelly.

Scientists study the invertebrates and identify what species they are.

We found out that there is a huge biodiversity of invertebrates living in the ocean and that some can grow really big such as the sea slater and scale worm.

Sea Slater

Scale Worm

Basket Star

This basket star has lots of arms that would be extended out when it is in the sea to catch food.

The invertebrates are collected by scientists on NIWA's boat called the Tangaroa.
If you want to find out about some of the different voyages that the Tangaroa has been on click here. You will also be able to read about what Miss Harrison did when she was on board the Tangaroa.

Fantastic Flubber

This week at science club we made flubber.

Flubber is a bouncy, rubbery substance.

The science behind it

Most liquids, like water, are made up of molecules that are not linked together. These are called monomers. These liquids flow easily and are not sticky when you touch them.

In some substances the monomers are linked together in long chains. These are called polymers. These long chains do not flow over each other easily. Liquid polymers tend to be gooey, sticky and hard to pour.

Flubber is an example of a cross-linked polymer. This means that the polymer chains are linked and this stops the molecules moving over each other.

How to make flubber

First you put 25ml of PVA glue into a beaker. Then an 2 drops of food colouring and stir to mix. While stirring slowly add 15ml of borax solution. Keep stirring vigorously until the flubber starts to form. Finally, roll the flubber in your hands. Dry hands work best. Keep rolling until it forms a rubbery, smooth ball.

Properties of Flubber

• When you feel the flubber it is all rubbery.
  
• When you pull the flubber quickly it will snap like a piece of plastic.
• When you stretch the flubber slowly it stretches more.
• Flubber balls can bounce on the table.
• We found out that flubber can be used as a rubber.
• If you put your flubber on some pencil writing the writing prints onto the flubber.

If you add too much borax to the mixture the flubber does not work and goes all sticky and gooey. The mixture was really wrinkly.


To start with lots of us had problems getting the mixture to work. But we persevered and finally it worked.

Playing with flubber is really addictive. We couldn't stop squishing, rolling and bouncing it.

What do hokey pokey and pumice have in common?

Well - quite a lot actually!

On Friday at Science Club we made hokey pokey.

First we had to measure out the sugar and golden syrup into a saucepan.

This mixture then had to boil for 7 minutes.

After 7 minutes the baking soda was stirred in. Suddenly the golden liquid when lighter and puffed up. When the baking soda was added to the hot mixture the reaction that occurred produced a gas that made the hokey pokey mixture expand and puff up.

The hokey pokey was then spread on a tray to cool and set.

When the hokey pokey was cut up we could see that there were lots of tiny holes inside.

Next we looked at different rocks and discovered that hokey pokey looked and felt a lot like pumice. They both had small holes and were really light.

Pumice is a type of rock that is produced in volcanoes. Miss Harrison challenged us to think about how the pumice might be made. After thinking for a while we came up with this explanation.

When a volcano erupts lava comes out of the volcano. At the same time there is a lot of gas coming out of the volcano. The gas mixes with the lava and makes it puff up (just like the baking soda did in the hokey pokey mixture) to produce the light and air filled pumice.

I wonder if we are right.

What does it feel like?

A group of Year 1 students were learning about their 5 senses. The 5 senses are:

• Touch
• Taste
• Hearing
• Seeing
• Listening

When you touch things they feel different. Some feel hot, cold, hard, soft, smooth or rough.

Sometimes it is hard to decide what something feels like.

We used our fingers to touch lots of different thing and work out what they feel like.

The leaf felt smooth and cold.

The hot water bottle felt hot.

Does sound travel through a table?

This is the question that Year 1 students were asked.

Lots said NO! The table is too thick. The table is not air.
Some said YES! The table will vibrate and make the sound go through it.

Who was right?

The students got to investigate to find out.


One student put their ear on the table and at the other end the student gently tapped the table.
Could the listener hear the sound? YES!

This is because the tapping makes the table vibrate which sends the sound wave through the table to the listener's ear.

Next they tested whether sound would travel through the table and then through other things like a book or shoe.

The results of the investigation was recorded to show how well the sound went through the object. Lots of ticks means the sound travelled through well and was easy to hear. Only a few ticks means the sound was harder to hear.

School Gen Update

Have a look at how much power we are generating with our solar panels. Click here.

Today it is cloudy so we won't be creating as much energy as yesterday when it was sunny.

Plankton Poem

A8 has been learning about plankton, food chains and poetry. So Emily decided to write a diamante poem about plankton and sharks.

PLANKTON
Microscopic green
Floating, Sinking, Drifting
Antennae Arms...........Teeth fins
Swimming, finding, chewing
Gigantic grey
SHARK

Marine Ecosystems and Food Webs

This week the Year 5 an 6 students have been learning about marine ecosystems and food webs.

An ecosystem is a group of organisms (plants and animals) living in a certain habitat that interact with each other.

A food web shows how plants and animals depend on each other for food and energy.

Students were given some notes made by a marine biologist about organisms in a rock pool and what they were eating.

The challenge was to use the evidence to develop a food web.

On the food webs the arrows show the direction that the energy is going. For example - when a crab eats some seaweed the energy is going from the seaweed to the crab.

It was hard work and everyone had to think about the evidence they were given. The students were thinking like scientists.

It was easier when students worked together on the task, sharing their knowledge.

Ocean Acidification (Part 2)

These eggs have been in vinegar for about 5 days. As you can see the shell is coming off.
When you touch the eggs they feel soft and rubbery.
Some of the eggs broke open when you poked them because the shell was so soft.

This experiment demonstrates what happens to the shells of animals in the sea if the sea becomes too acidic.

A young scientist

Levi (Year 1) has been learning about sound at school. So he went home and did some science investigations of his own.

He found out that sound vibrations travel along a string and you can make a simple telephone out of paper cups and string.

Well done Levi.

Ocean Acidification

Did you know that the ocean absorbs carbon dioxide from the air?

Well the year 5 and 6 students know this. They also found out that when lots of carbon dioxide goes into the ocean, the ocean can become more acidic. This is bad news for animals living in the ocean who have a shell or exo-skeleton made from calcium carbonate. (eg - shell fish, coral, crabs)

When calcium carbonate is exposed to acid it starts to go soft. This means that the animals shells or exo-skeletons wont grow so well.

To demonstrate this we put an egg into vinegar and watch what happened. (Egg shells are made from calcium carbonate and vinegar is an acid.)

Our eggs are still in the vinegar so check back next week to find out what happened.



We also tested a range of substances to work out if they are acids, bases or neutral.

We tested milk, soap, vinegar, sugar, baking soda, and dishwashing liquid.

To test each substance we dropped a small amount on indicator paper.

Red/Pink = acid
Purple = neutral
Blue/Green/Yellow = base

Lemons were definitely an acid. They made the indicator paper go really red.

Sounds can be LOUD or quiet

Our clever 5 year old scientists found out that sounds can be LOUD or quiet.

To make a loud sound they found out that you had to hit the drum hard and quickly and to make a quiet sound they had to hit the drum softly and slowly.

The picture above shows how an ice cream container was used to make the sound of the rubber band twang louder. This is just like how the body of the guitar makes the sound of the strings louder.

Exploding sandwich bags - well nearly!!!

This week at science club we investigated exploding sandwich bags.

We knew that if you mixed vinegar and baking soda together you get a reaction that produces fizzing, foaming and bubbles. This is caused by the carbon dioxide gas produced during the reaction.

The idea was to trap this gas inside the zip-lock bag, stand bag and watch it pop.

But....

The bags did expand when they filled with the carbon dioxide gas but there was not quite enough pressure to pop open the bag.

Here you can see the bag all puffed up.

So we investigated what the best recipe was to use by altering 1 variable at a time. We tried using more or less vinegar and more of less baking soda.

In the end we found out that more vinegar makes a better reaction and finally we did get at least 1 bag to EXPLODE!