Little Water Experiments
FoundationWater has no colour or taste; it flows and can dissolve some things. Try float-and-sink, dissolving and capillary action at home.
- Water has no colour or taste and no fixed shape.
- Some things float and some sink — test to find out.
- Sugar and salt dissolve in water; sand does not.
文體小知識：說明文帶你做三個水的小實驗，每個都有材料和步驟，在家就能當小科學家。
§Text Passage
1What does water look like? It has no colour, no smell and no taste — it is a clear liquid. Water has no fixed shape: poured into a round cup it is round, into a square box it is square. A few little experiments let you see it all.
2Experiment one, float and sink: fill a basin with water and gently place a block, a coin, a bottle stopper and a paper clip. The block and stopper float; the coin and clip sink. Guess first, then test, and write down the results — that is an experiment record.
3Experiment two, dissolving: put a teaspoon of sugar into clear water and stir. The sugar disappears and the water turns sweet — this is dissolving. Try a teaspoon of sand instead: it sinks to the bottom and never disappears, because sand does not dissolve in water.
4Experiment three, walking water: roll a paper towel into a strip, one end in a cup of blue water, the other in an empty cup. After an hour, blue water appears in the empty cup, because water climbs slowly along the tiny gaps in the towel — this is capillary action. Tidy up afterwards, draw your results, and you are a little scientist!
1Summary 重點摘要
Water has no colour or taste; it flows and can dissolve some things. Try float-and-sink, dissolving and capillary action at home.
2Vocabulary cards Vocabulary
Something that flows and has no fixed shape, such as water.
When something mixes into water and disappears, like sugar in water.
To stay on top of the water, like a block floating.
To fall to the bottom of the water, like a coin sinking.
Trying things by hand to find answers.
To watch carefully what happens in an experiment.
Water climbing slowly upward through tiny gaps.
Writing or drawing down what you observed.
3Step by step Steps
- Step 1: Know water's featuresWater is a clear liquid with no colour, no smell and no taste, and it has no fixed shape. Pour water into a round cup and it becomes round; pour it into a square box and it becomes square. A few little experiments let us see these features with our own eyes. Example: pour the same cup of water into containers of different shapes; the amount of water never changes, yet the shape keeps following the container. A common mistake is thinking water has a shape of its own; in fact water has no fixed shape and changes with its container, which is exactly what a liquid is like.
- Step 2: Float and sinkIn water, what floats and what sinks? Before the experiment, make a guess: between the block and the coin, which floats? Then place them gently into the water to test. The block rests quietly on the surface, while the coin sinks straight to the bottom. Why guess first? Guessing and then testing is how scientists look for answers, and it helps us remember far better. A common mistake is thinking big things always sink and small things always float; size is not the reason — the material and the weight are what matter, and only an experiment can confirm it.
- Step 3: DissolvingSome things slowly disappear when put into water — this is dissolving. Stir a teaspoon of sugar into water and it gradually vanishes, leaving sweet sugar water; stir sand into water instead, and the sand stays at the bottom while the water keeps no taste. Comparing things that dissolve with things that do not helps us understand the power of water. Example: salt and sugar dissolve in water, but sand and stones do not. A common mistake is thinking the sugar has truly gone; it has only broken into tiny, tiny particles spread through every part of the water — one sip and the sweetness is still there.
- Step 4: Capillary actionWater can creep slowly upward through tiny gaps — this interesting trick is called capillary action. Roll a paper towel into a strip, put one end into a cup of blue water and the other into an empty cup; an hour later, blue water appears in the empty cup. This amazing result shows that water can move slowly along the tiny gaps in the towel, as if it were walking. Why learn this? A towel soaking up water and a plant carrying water to its leaves work the same way. A common mistake is thinking water only flows downwards; inside tiny gaps, water can climb upward too.
- Step 5: Follow experiment rulesBefore doing an experiment, set some small safety rules so everything goes smoothly. Spread newspaper on the table first to keep it dry; never drink the experiment water, because it may not be clean; after the experiment, tidy up the water and materials and wipe the table. Why follow the rules? An orderly experiment is a safe one, nothing gets lost, and you can continue next time. A common mistake is playing while experimenting and splashing water everywhere; this is not only unsafe, it also makes the results inaccurate.
- Step 6: Keep a recordWrite down the results of an experiment right away, so they can be compared and remembered later. Draw a chart with a float column and a sink column, list every item you tested, and tick the right box; a dissolving experiment can also have two columns, dissolves and does not dissolve. Open your record and you can see at once which things float and which sink. Why is recording so important? Scientists discover patterns through their records. A common mistake is trusting memory alone; as days pass the details fade, and only words on paper stay reliable.
4Diagrams Diagrams
5Worked example Example
Example: Ming stirs a teaspoon each of salt, sand and sugar into three cups of clear water. Which cups change taste?
- First sort the three materials: salt and sugar dissolve in water, but sand does not.
- The salt dissolves after stirring, disappears from sight, and the water turns salty.
- The sugar dissolves after stirring, and the water turns sweet.
- The sand does not dissolve but sits at the bottom, so that water keeps its taste; cup one turns salty, cup two sweet, cup three unchanged.
- Answer: The salt water and the sugar water change taste: dissolved salt makes the water salty and dissolved sugar makes it sweet. Sand does not dissolve but sinks to the bottom, so that cup tastes the same. The key is to sort out which things dissolve in water; what dissolves changes the taste, and what does not only settles at the bottom.
6Common mistakes Mistakes
7Quick check Quick check
Q1What colour is pure water?
Q2What happens to a block in water?
Q3Where does sugar go after stirring in water?
Q4What is it called when water climbs up a paper towel?
Q5Does sand dissolve when stirred in water?
8Recap Recap
- Water has no colour or taste and no fixed shape.
- Some things float and some sink — test to find out.
- Sugar and salt dissolve in water; sand does not.
- Capillary action: water climbs up through tiny gaps.
- Experiments: guess first, test next, record always.