Equipment preparation: balance, measuring cylinder, water, metal block and string.
1. Special measurement method of water injection
Weigh the mass m of the metal block with a balance, inject an appropriate amount of water into the measuring cylinder, read the volume as V1, tie the metal block with a string, put it into the measuring cylinder, and immerse it, and read the volume as V2.
expression: ρ=m/(V2-V1) Measurement of solid volume: The density of insoluble water is higher than that of water, and the volume density is lower than that of water by drainage method, pressing method, binding method, hanging method and sand burying method.
2. Special measurement method for water-saturated solution
Sand-burying shaping method If the measured objects are easy to be shaped, such as potatoes and plasticine, they can be shaped into cubes, cuboids, etc., and then the relevant length can be measured with a scale, so that the object volume can be easily obtained.
3. Special measurement method of saturated solution
Scheme 1: Measure the mass m of the sugar block with a balance, then put the sugar block into a measuring cylinder, pour a proper amount of white sugar to bury the cube, shake the measuring cylinder to flatten the surface of white sugar, record the total volume V1 of white sugar and cube, take out the cube with tweezers, shake the measuring cylinder again to flatten the surface of white sugar, and record the volume V2 of white sugar, then ρ.
Scheme 2: Wrap the candy with plasticine and put it into water, measure the total volume V1 of water, plasticine and candy, take out the sugar water, measure the volume V2 of water and plasticine, and calculate the candy volume V=V1-V2. Calculate the density of candy by formula.
scheme 3: measure the mass m of three cubes with a balance, pour an appropriate amount of water into the measuring cylinder and add white sugar, stir with a glass rod to make a saturated solution of white sugar, and record the volume V1 of the saturated solution. Then, put three cubes into the saturated solution and record the total volume V2 of the saturated solution and sugar cubes, and the density will be 12VVm.
scheme 4: measure its mass with a balance, measure its length, width and thickness with a scale, calculate its volume, and then calculate the density of the candy bar with a density formula.
iv. special measurement method of buoyancy method
spring scale equipment: spring scale, metal block, water and string: tie the metal block with string, weigh the gravity g of the metal block with the spring scale, completely immerse the metal block in the water, and weigh the apparent weight g of the metal block in the water with the spring scale.
expression: ρ=Gρ water /(G-G/) Example: measuring cylinders are not allowed, and only spring scales are used as measuring tools. How to measure the density of a small stone?