Science Show!

Here is a preview of some of the experiments we will be doing for Year 3 students on Friday:

And here is one of the experiments being done for the Year 3 students:

Exam Outline

The resources/activities in blue are the ones provided by Mr Nicoll. The ones in red are ones we can do/prepare ourselves.

Transpiration

For homework, we had to COMPARE AND CONTRAST nutrient transport in plants and in humans.

The set up for one group. The water in the petrie dish has purple food colouring in it.

One group's results: notice the food colouring in the xylem tissue.

Leaves

We agreed that plants only need leaves to absorb sunlight and carbon dioxide for photosynthesis. They actually prevent water entering them, except from the roots via the stem and veins.

The key parts of the leaf cross-section that we were encouraged to talk about were: wax cuticle, palisade cells, air spaces, stoma, guard cells, and the spongy mesophyll.

Pollination and Fertilisation

We used our sciPads to find out about pollination and fertilisation. We also had to think about how non-flowering plants reproduce.

Flowers - Introduction

Designing a Fair Test

Today was the first day of preparing our investigation on the effect of plant nutrient additives on plant growth.

STEP ONE: Method Described (Multistructural)

1. 180-190g of strained soil is weighed and added to a biodegradable punnet.
2. Three 2cm deep wells are made in the soil (evenly spaced out).
3. One sugar snap pea seed is put into each well. The wells are covered with soil.
4. 20mL of tap water is measured in a measuring cylinder then added evenly to the top of the soil.
5. The class's punnets are put in trays and placed in the window of the resource room.
6. 20mL of tap water will be added every Monday and every Friday.
7. The height of the plants will be recorded on Monday every week for 6 weeks.

We have yet to decide how to investigate the effect of the plant nutrient additives we have purchased - this is tomorrow's job!

STEP TWO: Variables Analysed (Relational)

Mr Nicoll identified some key variables that were controlled by using this method. We then discussed why it was important to control these variables:

Completing this HOTMap is our homework tonight.

OUR RESULTS

Cool Onion Cell Photo

This is a photo I took of the Onion Cells that we were studying under the microscopes today. I managed to snap this shot with my iPhone 4S.

Ecology Assignments

Over the past few weeks, the class have been doing an inquiry about a New Zealand animal. They needed to find out about its habitat, adaptations, place in a food web, and about its chances of survival. The following links are some of the websites/blogs which were made. Other students presented their findings as: written reports, posters, speeches, or on display boards.

http://nzbluepenguin.weebly.com/

http://newzealandweka.weebly.com/

http://redstagnz.weebly.com/

http://nzsnapper.blogspot.co.nz/

http://brittanyfindlayfantail.blogspot.co.nz/

http://blueduckstac.weebly.com

Food Chains

Today we learned about food chains, so we could use this information to help us with our Ecology Assignments.

Food chains represent the energy flow and feeding relationships between a group of organisms in a particular habitat or ecosystem:

All food chains start with a producer. They are able to make their own food using sunlight, carbon dioxide and water; this process is called photosynthesis.

Adaptations

As part of our assignment, we need to evaluate the adaptations of our New Zealand/Aotearoa organism. Today, we learned about adaptations and have to finish this work for homework:

Elements - Metals and Non-Metals

Elements and Pure Substances

Over the last couple of weeks, we have learned how to separate mixtures. We have been separating them into their pure substances.

Today, we learned what some of those pure substances are:

• elements
• compounds

Some elements exist as atoms, while some exist as molecules. The elements are all found on the Periodic Table, which has their special symbol.

Compounds are formed when different elements react. This means they join together chemically, forming bonds between the atoms. Compounds can be molecules (like some elements) or they can be ionic. We learn more about these in the next few years of Science and Chemistry...

Our task today was to classify all matter from what we have learned in the last few weeks and in today's lesson.

Chromatography

Chromatography is a method used to separate differently-coloured pigments.

We did an experiment to help us understand what chromatograhy really is and how it works. Thank you to Angus and Flynn for the results:

The Set Up (BEFORE)

The Results - the colours have separated (AFTER)

Separating Solutions - Evaporation and Distillation

First, we had to DESCRIBE Evaporation and Distillation:

For homework, we need to EVALUATE wen each method should be used:

Evaporation

Today, we learned about one way to separate solutions: evaporation.

We did an experiment (p36 in the Scipad) to help create a sequence to explain how evaporation works.

This was our apparatus. We have to DESCRIBE what happened
and EXPLAIN how this worked.

One of the groups' results - it is a solid now, not a solution!

Separating Suspensions

I was so impressed by Daniel's piece of writing that I felt it needed to be shared:

"Decantation is a very quick method for separating a mixture of a liquid and a heavier solid. This works by first letting the solid settle on the bottom of the beaker, and then you can pour the water off the top of the solid without disturbing it. The advantage of decantation is that it is very quick, but it is also rough and does not always work the way it is meant to. It cannot be used to separate a mixture of a liquid and a light solid, like sawdust and water. The particles of sawdust are suspended in the water. They are so light that they do not sink down to the bottom for a long time.

Filtering is a very good method used to separate solids from liquid. This method works by placing a sieve or micron paper over a container or beaker and pouring the mixture onto the filter. The filter separates the solid from the liquid and the liquid passes through without carrying the solid. For example with the sawdust experiment, the sawdust stayed on top of the filter paper while the water passed through. This is because the sawdust bits are too big to fit through the paper, but the water is not, so it passes right through.

A Centrifuge is a piece of equipment, usually driven by an electric motor, though some older models were spun by hand. The Centrifuge puts an object in rotation around a fixed axis, applying a force perpendicular to the axis. A Centrifuge is also used to separate the components of blood in blood banks. A Centrifuge is the most efficient type of filter, but it lacks portability and simple nature. You cannot just go out camping and take a centrifuge with you. First is requires a power source, and secondly it is too big to just chuck in your backpack.

In my personal opinion, I think that the paper filter is the best option. I think this because this method is easy to carry out, it can be carried out nearly anywhere, it does not require a power source to be performed, and it is also very efficient. Using a 1-micron paper filter you can remove harmful diseases from water is you are out tramping and avoid becoming severely ill. Although a paper filter is a very good option, it is not always the best. If you were cooking potatoes or pasta it would just be so much easier to apply decantation. Also if you are giving blood it is much quicker and easier to use a Centrifuge to separate the different parts of blood rather that using paper.

By Daniel Coulter

Solutions and Solubility

Today, we learned about solutions. If substances are soluble, they dissolve to make a solution. Some solutions have a lot of solute in them - we call these concentrated. Some have very little solute in them - we call these dilute.

How easily something dissolves is called its solubility. Some substances dissolve very easily (so have high solubility). Some are difficult to dissolve (so have low solubility).

Suspensions

A suspension is a mixture made when a substance is insoluble, so the substance floats or sinks. There are three possible ways to separate suspensions:

1. decanting
2. filtering
3. centrifuging

In today's lesson, we had to decide which method is the best. Is there actually a "best" method. We used research, an experiment (p29) and a case study (p30) to help with this.

Primary Colours

Today, we learned about the primary colours of light. These are a little different to the primary colours of paint. This is because paint reflects fewer colours when we mix the colours together. This is called colour subtraction. On the other hand, when we mix the primary colours of light, we add the colours, so more light is let through.

Then, we had to do some research and produce a report or poster about one of the following topics:

• How do we see colours?
• How does theatre lighting work?
• How do televisions work?