Our New Science Topic in Year 5!

In Year 5, we’ve started a new topic this week, Materials, and we’ve started with an investigation. We learned the difference between dissolving and melting and we decided to find out which materials were soluble and which were insoluble. We chose accessible materials such as sugar, salt, chalk, sand, gravy granules, flour, rice and coffee granules and we mixed them with cold water to see if they would dissolve.

In order to ensure that we made a fair test, we used the same measuring jug, the same amount of water and we stirred the mixture for the same amount of time using the same spoon.

To decide whether the material was soluble or insoluble, we had to look closely to see if the material appeared to have disappeared (when in actual fact it has mixed to create a new solution!)

We found that the salt, sugar, gravy granules and coffee granules were soluble materials whereas the chalk, rice, sand and flour were insoluble. In some cases, the water was discoloured so we had to use a spoon to scoop the bottom of the measuring jug and see if the material had dissolved.

The second part of our experiment was to see how different variables affected the rate sugar dissolved in water. Ensuring a fair test was essential and we had to make sure we only changed one variable each time. The children were separated into small groups and each group chose their own investigation question:

1) Does the amount of water affect how quickly sugar dissolves in water?

2) Does the temperature of the water affect how quickly sugar dissolves in water?

3) Does the number of stirs affect how quickly the sugar dissolves in water?

4) Does the amount of time spent stirring affect how quickly the sugar dissolves in water?

5) Does the amount of sugar affect how quickly it dissolves in water?

 

Unfortunately we had to restart the experiment because most of us fell into a trap. We mixed sugar and water and then the next time we carried out the experiment, we used the same water (which now was a mixture of sugar and water) so the test was no long fair! The next time we carried out the experiment, we ensure that we washed out the measuring jug and used fresh water from the tap each time.

 

Once we completed the experiment, we drew some very interesting conclusions:

• the more water we used, the quicker the sugar dissolved.
• the greater the temperature of the water, the quicker the sugar dissolved.
• the greater the number of stirs and the more time spent stirring, the quicker the sugar dissolved.
• the greater the amount of sugar, the more slowly it dissolved.