（1） Use the thermometer correctly

（2） Get to know the alcohol lamp

（1） evaporation of water

（2） boiling of water

（3） Freezing and melting of water

（4） Three states of water

①Water can dissolve salt and baking soda, but it cannot dissolve sand.

② The amount of salt and baking soda that the same water can dissolve is different. Under the same conditions, the amount of salt that water can dissolve is greater than that of baking soda.

③When doing dissolution experiments, add salt or baking soda in portions, so that the data obtained will be more accurate.

④The speed of salt dissolution in water is related to the temperature of the water. The higher the water temperature, the faster the dissolution speed.

⑤The speed of salt dissolution in water is related to whether the liquid is stirred. The faster the stirring, the faster the dissolution speed.

①The process of salt dissolving in water is a reversible process.

② Sand can be separated from water by filtration.

③Salt and water can be separated by evaporation. The salt in the solution cannot evaporate along with the water.

④ Heating and evaporating the solvent makes the solution change from unsaturated to saturated. If the evaporation continues, the excess solute will precipitate in the form of crystals, which is called evaporation crystallization.

（1） Compare the changes in plasticine, paper and water

（2） Physical change means that although the state of a substance has changed, generally speaking, the composition of the substance itself has not changed. For example: changes in position, volume, shape, temperature, pressure, and the mutual transformation of gas, liquid, and solid states. (Such as the three-state changes of water) etc.

1. feature:

2. effect:

3. There is air all around us.

4. Stones and water will not leak easily when put into an open cup, but air will leak easily when put into an open cup.

5. The air must be put into a sealed container so that it is not easy to leak. If you want to pass some air to other students or other places, you must put it into a sealed container.

6. Compared with ordinary substances, air has these characteristics: it is easy to leak, is very light, can make the bag bulge, and makes the bag feel soft to the touch after it is bulged, and it will flow and be difficult to grasp...

7. Objects are divided into three types: solid, liquid and gas. Water, soy sauce, cola, etc. are liquids and will flow; stones, sand, wood blocks, etc. are solids and have fixed shapes; air and water vapor are gases, which have no fixed shapes and will flow.

1. Air, like water and rocks, can take up space.

2. When doing the experiment of making paper not wet, the paper ball should stick to the bottom of the cup to prevent it from falling into the water.

3. Poke a small hole at the bottom of the cup to let out the air in the cup so that it no longer takes up space in the cup, and the water in the cup will slowly fill up.

4. Use a pump to hit the cup from the bottom. The air occupies the space in the cup and the water in the cup will be slowly squeezed out.

5. In the story of the crow drinking water, the crow uses pebbles to squeeze the air out of the bottle. The air occupies less and less space in the bottle, and the water in the bottle slowly rises.

1. The space occupied by air is easy to change, but the space occupied by water is not easy to change.

2. The space occupied by air is easily compressed, and compressed air is elastic; the more compressed the air, the stronger the elasticity.

3. The space occupied by water is not easily compressed or expanded.

4. The space occupied by air is easily expanded, and the expanded air has the ability to return to its original state, thus generating a force.

5. Compared with the air in its original state, the compressed air has the same mass and the distance between air particles becomes smaller.

6. Compared with the air in its original state, the expanded air has the same mass, but the distance between air particles has become larger.

7. The air compression gun uses the elastic force generated by the compressed air to launch the "bullet".

8. Use the elasticity of compressed air to create inflatable tires, inflatable castles, inflatable cushions, etc.

1. Wood has quality. Water has quality. Air also has quality; air will always fill everywhere.

2. A simple small balance can be used to study whether the air has quality.

3. Balance - put an inflated ball on one end and beans on the other end. If it is balanced, it means that the mass of the inflated ball and the beans are equal.

4. If you continue to inflate the ball, the small balance will lose its balance. This is because air has mass: as air is added, the total mass of the ball and air will be greater than the total mass of the beans.

5. Blow the inflated ball with 10 cylinders of air, and continue to add beans to the other end of the small balance. When the balance returns to balance, the mass of the 10 cylinders of air that was hit is equal to the mass of the added beans.

6. If you let out part of the air in the ball, the small balance will lose its balance. This is because the air has mass; if the air is let out, the total mass of the ball and the air will be less than the total mass of the beans.

1. Use lighter objects such as paper clips or mung beans to adjust the balance of the small balance, the more accurate the adjustment results will be.

2.20 cylinders of air and quantitative paper clips: light and small objects such as mung beans have the same mass, indicating that the air has mass, but the mass of the air is very light.

3. In life, we can use balances, electronic scales and other tools to measure the mass of small and light items such as paper clips and mung beans.

4. There is a lot of air around us, and the total mass of that much air is very heavy.

1. Hot air is lighter than cold air and will float above cold air.

2. When the air in the hot air balloon is heated, the mass per unit volume is lighter than the original cold air, and the hot air balloon rises.

3. Let the hot air in the hot air balloon slowly cool down (cool). The air mass will be greater than when it was hot, and the hot air balloon will slowly descend.

4. When doing the "hot air balloon" simulation experiment, pay attention to fire safety.

5. When doing a "hot air balloon" simulation experiment, the plastic bag chosen should be larger and lighter, so that more hot air can be filled in and it will be easier to lift off.

6. Before heating, the plastic bag is flat and cool: after heating, the plastic bag will slowly bulge up, and the air will slowly heat up, creating an upward pulling force.

7. Kongming lanterns are made using the principle that hot air is lighter than cold air.

8. Kongming lanterns pose serious fire hazards, so try not to set them off.

1. The flow of air creates wind.

2. We can use fans, open fans, open doors and windows, etc. to make the air flow quickly to create "wind".

3. In the wind simulation experiment, the candle is lit to increase the temperature of the surrounding air; the temperature of the air away from the candle flame becomes relatively low, and the air flows, and wind is formed.

4. When doing wind simulation experiments, using small paper strips (or small fans) placed at the air outlet can help us better observe whether wind is generated and the size of the wind.

5. Natural wind is mainly caused by the flow of air due to different temperatures.

6. The difference in air temperature in nature is mainly caused by sunlight radiation.

1. Air is a substance. The earth is surrounded by a thick layer of air, which is called the atmosphere.

2. There are traces of air in the air, underground and water. We can find traces of air in the air, underground and water through scientific methods.

3. People use air to do more things that are beneficial to us; natural disasters such as tornadoes caused by air flow sometimes cause heavy losses to people.

4.

1. Weather refers to the temperature, warmth, cloudiness, rain, snow, wind, etc. of the atmosphere in a place within a short period of time.

2. The weather is always changing, which affects our lives and all living things on the earth.

3. By recording the weather calendar, it can help us understand the weather changes in a certain area within a period of time.

4. The weather calendar generally records date, time, temperature, rainfall, cloud cover, wind direction and wind speed, etc.

5. Common weather symbols.

Measurement of air temperature

Measurement of rainfall

wind observation

cloud observation

1. Organizing, summarizing and analyzing weather information can help us understand certain characteristics of the weather and understand some of the laws of weather changes.

2. The long-term average weather conditions in a place are called climate.

3. Weather forecasts are mainly produced and released by meteorological departments distributed around the world. There are roughly five steps in making a weather forecast: data collection, numerical weather forecasting, meteorologists making forecasts, weather consultation, and issuing weather forecasts.