7A test pH

During the last couple of lessons 7A have used litmus and universal indicator papers to assess the acidity or alkalinity of various substances.

The litmus paper comes in two colours blue and red.

One drip of solution is all it needs.

Compare the colour and write down the result

Lots of substances to test

Then clean out the petri dish

And start the next substance

Recording all results

And comparing colours

All very busy

Y5 get evaporating

Today Y5 investigated some conditions that affect the rate of evaporation.

First they got a tissue and weighed it

They weighed another and found they were very nearly the same mass

Then they added the same amount of water to the two tissues

One tissue was spread out and another folded

Which would lose the most mass in 20 minutes

Next we tried one covered in a petri dish and another in the open

Both with the same amount of water

So it was a fair test

Then one in a fan blast and another in the calm
We left these all for 20 mins and then weighed them again to see which had lost the most water

Spread out, not covered and under the fan worked best for evaporation. we did another experiment which showed us that the higher the temperature the quicker evaporation happens.

Y8 reduce copper oxide

Y8 used carbon to reduce copper oxide

This is the copper oxide - a black powder

This is carbon - a grey/black powder

they were mixed together in a test tube

and heated very strongly

Soon a glow spread through the mixture

And it was time to tip the products out of the test tube

Examining them closely we found there were tell tale pinky brown signs that we had made copper

Copper oxide + carbon => copper + carbon dioxide

Another successful experiment

Y8 reactivity series experiments

Y8 tested different metals with water.

They needed to add the metal to water and see if there was a reaction

Some did not react so they tried again with hydrochloric acid

If the metal reacts then hydrogen is given off.

7A investigate pondeeed

Pondweed photosynthesises underwater. We can use this plant to help in our studies of photosynthesis.

We added bicarbonate of soda to the water so there would be lots of carbon dioxide to promote photosynthesis

Two spatulas each so its a fair test.

Mix thoroughly and then add the pondweed.

Make sure you use 10cm of pondweed each so its a fair test.

Weigh the pondweed down with a paper clip

Now put it by the light and see the bubbles of oxygen coming off.

8A test metals affinity for oxygen

Reactivity Series experiments include playing one metal off against another for oxygen.

You need to take one metal

And a different metal oxide

Mix the two powders together.

And heat them in a roaring flame

They need to be powders so they have a large surface area.
And they need to be mixed so every particle of metal oxide is touching a metal particle.

Then look for signs of a reaction like smoke, glowing or a change in appearance.

Then repeat with a different metal and metal oxide

But make sure you note down all of your results carefully.