How to measure the density of oil with a plastic bottle, a bucket of water, a ruler, a pair of sciss

The conditions don't give oil, but there should be oil 1Cut off the upper end of the plastic bottle, leaving only a relatively uniform cylindrical shape of the long partPut a few pebbles into the cut plastic bottle, put the plastic bottle in the water, and mark the place where the water floods a (the mark is a from the bottom of the plastic bottle), 3

Make a mark x at the top of the plastic bottle, and do not take out the stones in the plastic bottle, do it twice: the first time the oil is raised to the height of x in the plastic bottle, and then put it into the water, and note the position of the water flooding a; Pour the water into the plastic bottle for the second time to the height of x, put it in a bucket like water, and note the position of the water flood. Therefore, the density of oil is measured to be (a-x) (b-x) times of the density of water (a is smaller than b, that is, the density of oil is smaller than water).

Measuring principle: Archimedes' law 1, put the stone into a plastic bottle; 2. Put the bottle in water and write down the height h1 of the bottle when it is immersed in water; 3. Take out the bottle and wipe it dry, then put it in oil, and note the height of the bottle immersed in water h2; Let the cross-sectional area of the bottle be such that the buoyancy experienced by the bottle together with the pebbles is equal to its gravity, which is equal to the amount of water discharged when it is placed in the water: Water gsh1 is the same in oil Oil gsh2 is equal Water gsh1= oil gsh2 Water is known, gs can be about to go, oil can be found.

If the ruler can be leveled, it is not simple: know p water, find p oil, process the cup into two identical containers, put the oil into one container, put the water at one end of the scale, put the container with water to the level at the other end, and then the volume of water (square of the radius x height) x p water get m water get m oil finally v oil So m oil divided by v oil to get p oil.

We know.

m v, so just know the mass and volume.

But we can measure volume, but we don't have the tools to measure mass.

So there is no way to use the drainage side quality method.

It can be done.

Cut off the part of the plastic beverage bottle that is not the cylinder.

It's the pointy upper part.

There was a bucket-like container left.

Fill this container with oil.

Place vertically in the water.

Why put it vertically can not be explained.

It must be floating after letting it, right?

Use a scale to measure the above and underwater parts.

The height on the water is on l.

What is underwater is underwater.

L down (L up + l down) is actually the following than the top all the bottom note、

The following equation is not a formula.

l l full == oil and water.

Then oil = l under l all* water.

Easy to read is rou oil is equal to rou water into l divided by l all you drop understand.

You can imagine the floating state of the ice, if it is an experimental design, it is recommended not to prove it.

Also, there is no high school entrance examination.

But there are definitely competitions.

If the ruler is 20 cm long, there are 7 different lengths, 1, 2, 4;19；18；16；20。

1. Twist into a straight method: use a string to wrap around the coin, mark both ends or cut off the excess part, then gently straighten, and put it on the scale to measure the length of the string, that is, the circumference of the measured coin.

2. Roller method: use the coin to roll along the wooden stick in a straight line, write down the starting point and end point of the coin rolling along the wooden stick in a straight line, and use a ruler to measure the distance between these two points is the circumference of the coin.

1 Make a circle.

2 Make a triangle with vertices on the hidden circle of the beam within the circle.

3 Make a perpendicular line on any two sides of the triangle.

4 The intersection of two perpendicular lines is the dot.

5 Measure the distance from the dot to the circle, and the radius is sharp.

6 The diameter is twice the radius of the rubber-based hall.

With the ruler as the bottom, a right-angled edge of the triangle plate is close to the ruler to form a right-angle space (bayonet) of disturbing the burning rock; The right-angled space is stuck on the cylinder's cylinder (note that it is perpendicular to the cylinder), and a point on the ruler is obtained where the cylinder touches it. The distance from this point to the triangle (to the right-angled end of the right-angle bayonet) is the radius of the circle, and the radius of 2 times is the diameter of the cylinder segment.

First press the red line, fold out 4 * 4 16 pieces, and then press the blue line to fold, of which the 4 triangles are 1 12, and finally the green line, the rest of the rest you should know.

First fold twice along the midline to make 4 parts.

Then divide the 4 parts into 12 in equal parts.