Primary 4 Science

We have been learning about where our water comes from and how it is made up. We learned about the water cycle, how water is made up, how water is cleaned and transported to our taps, how water can be polluted, how and why we should save water and today we looked at what happens when things are added to water. We had learned about the use of sand filters to clean water so we started by looking at what happens to sand when it is added to water – it sank and stayed the same so it was insoluble. We then looked at salt and discovered it was soluble because it dissolved into the water. We then experimented with hot and cold water, coffee granules, uncooked rice and oil to see whether they were soluble or insoluble. We checked the water temperature using thermometers and noticed some differences to the changes if the water was different temperatures. We the hypothesized (said what we thought would happen) before trying it out. We discovered that coffee granules are soluble but oil and rice are not. We noticed lots of interesting things about each substance eg some of the rice in the cold water floated then sank an hour later, the oil in the warm water formed lots of little bubbles before floating on the top as one big bubble like the cold water one and that the coffee granules dissolved faster in the hot water (although this wasn’t as obvious as it would be if it was done with boiling water). We had great fun!