How to Write a Physics Experiment Report? A dot timer for the first year of high school?

I found it for you at the bottom.

Principle. Electromagnetic dot timer is a kind of timing instrument that uses AC power supply, its working voltage is 4 6V, the frequency of the power supply is 50Hz, and it hits the dot every other day.

If the paper tape driven by the moving object passes through the dot timer, the dots on the paper tape record the time of the object's movement, and the dots on the paper tape also indicate the position of the moving object at different moments. By studying the spacing between the points on the paper tape, it is possible to analyze the motion of the object.

Experimental process. 1.Place the long plank flat on the lab table with the pulleys protruding from the table.

2.Fix the dot timer on the side of the board without pulleys and connect the circuit in parallel.

3.Tie a string to the trolley, and the rope is crossed over the fixed pulley, and the appropriate hook code is hung underneath.

4.Attach the paper tape that runs through the dot timer to the back of the trolley.

5.Make the trolley stop close to the dot timer, turn on the power, let go of the trolley, and let the trolley move.

6.Disconnect the power supply and remove the paper tape.

7.Replace with a new tape and redo it twice.

Experimental data and calculation formulas.

The formula v= s(n)+s(n+1) 2t in the dot timer to measure acceleration

s(n) refers to the displacement from the n-1st timing point to the nth timing point, and s(n+1) refers to the displacement from the n-th timing point to the n+1st timing point? s(n)+s(n+1) refers to the displacement from the n-1st timing point to the n+1st timing point. (i.e., the point of the requirement is included in the middle of them, i.e., n).

t refers to the time interval between two phase twist counting points (n-1 to n, n to n+1) where the phase twist counts occur. 2t is the sum of time intervals.

What they obtained was the average velocity of this displacement, i.e., the instantaneous velocity that could be approximated as the point n (the required point).

The distance between two adjacent counting points is s1, s2, s3....The time interval between the two counting points is t, according to s=at*t.

s4-s3=(s4-s3)+(s3-s2)+(s2-s1)=3at*t

In the same way, s5-s2=s6-s3=3at*t

Find a1=(s4-s1) 3t*t a2=(s5-s2) 3t*t a3=(s6-s3) 3t*t

Then find the average.

Summary of the experiment. 1.The power supply used by the dot timer is AC power supply, and the voltage of the spark dot timer is 220V.

2.The dot timer should be marked on the paper tape with the appropriate weight of the small dots, if it is a small horizontal line, the height of the vibrating needle from the copy paper should be adjusted to make it larger.

3.Do not install the carbon paper in reverse, after each paper tape, you should adjust the position of the carbon paper, if it is not clear enough, consider replacing the carbon paper.

4.To use the dot timer, you should first turn on the power supply, and then release the paper tape after the dot timer is stable.

5.When processing paper tape data, the displacement difference of dense points has a large measurement error and should be discarded; Generally, five points are counted as a counting point.

7.The dot dispenser cannot work continuously for a long time.

Write what you do, otherwise it's called a fake!!

As shown in the figure, it is a paper tape that can be verified by the real shouting of the research object to do uniform variable speed linear motion (the frequency of the low-voltage AC power supply connected to the dotting timer in the experiment is 50 Hz), and a counting point is taken every 5 timing points from the O point, and it is numbered in order according to the order of the dots, and s1=, s2=, s3=, s4=, s5=, s6=

1) The time interval between two adjacent counting points is s.

2) The acceleration of the object is a = m s2, and the direction is (fill in a b or b a).

Question added: Figure seepage bucket: <>

Purpose, Principle, Procedure, Data Processing, Summary The specific content has been added to it.

My Teaching Experience:

If you don't know it, just write the experimental steps first, think about why you do each step, and figure it out, that's how you learned physics, and I wish you to learn physics well.

Let's refer to the experiment report, it will be very detailed.

1. Fix the dot timer on one side of the long wooden board with a matching spiral clip. If there is no spiral clamp, you can knock a few long nails on the long wooden board and fix it close to the front and back of the dot timer; Some can also use large spring clips to clamp the dot timer to the edge of the long wooden board, but be careful not to affect the work of the dot timer.

2. Connect the paper tape that passes through the dot timer to the trolley. When operating, it is necessary to pay attention to clamping the paper tape tightly on the trolley, so as not to loosen the paper tape when the trolley is moving, and it can be clamped with a spring clip, but do not break the paper tape, so as not to break the paper tape when the trolley starts.

3. Connect the string with heavy objects across the pulley and connect it with the trolley.

4. When operating, we must pay attention to making the tension of the rope pass through the center of gravity of the trolley, so as to avoid the trolley rotating or shaking when the trolley advances.

5. Connect the dot timer to the power supply and let the trolley move on the horizontal long wooden plank; The dot timer starts working at the same time, typing a series of dots on the paper tape. When operating, try to hit several times, do not make the point too dense or too evacuated, if you feel too dense, you can increase the weight tied under the rope of the pulley, and reduce it otherwise.

6. Remove the paper tape, discard the denser points at the beginning, find a starting point in the place that is convenient for measurement, and take the time of each five times as the time unit, that is, t=. Start with the first dot on the tape and mark 0, 1, 2, 3 ,...... every 5 dotsLet the distance between the two adjacent counting points be s1 respectively'，s2'，s3'，……

7. Measure the displacement S1'，s2'，s3'，……Calculate the difference between the displacements of two adjacent neighbors s1=s2'-s1'，△s2=s3'-s2'，△s3=s4'-s3'，……

8. Use the formula a= s t 2 to calculate the acceleration a1, a2, a3 ,......value.

9. Find the acceleration a1, a2, a3 ,......, which is the acceleration of the straight motion of the trolley to accelerate uniformly.

1.Objective: To practice using a dot timer to measure the speed at which the hand pulls the paper tape and describe the movement of the hand.

2.Experimental equipment: dot timer, AC power supply, paper tape, scale.

3.Experiment Log**: Record the displacement change every five points (seconds) and note the velocity value.

4.Make a V-T image based on the data.

5.Summary of the experiment: the movement of the hand in what state it is.

Write the purpose of the experiment first, the experimental equipment, the experimental principle, the steps, and then analyze the error.

Purpose of the experiment Experimental principle Experimental instrument Experimental procedure Data processing.

Conclusion: In order to reflect the motion of the object more intuitively, we can use the V-T image to represent the velocity with time. The Cartesian coordinate system is established with velocity v as the vertical axis and time t as the horizontal axis, and the points are traced in the coordinate system according to the instantaneous velocity values corresponding to different times calculated, and finally the points are connected by a smooth curve to obtain an image that can describe the relationship between velocity v and time t.

Precautions. 1) The power supply voltage should meet the requirements, and the electromagnetic dot timer should use an AC power supply below 10V; The spark timer uses 220V AC power.

2) Before the experiment, check the stability and clarity of the dots, and adjust or replace the equipment if necessary.

3) When using the dot timer, you should first turn on the power supply, and then pull the paper tape by hand after the dot timer is stable.

4) When pulling the paper tape by hand, the speed should be faster to prevent the dots from being too dense.

The conclusion is derived from the analysis, summary and induction of the specific experimental data, and the calculated speed value is obtained by dotting the timer speed. The calculation is based on the relationship between the average velocity over a period of time and the instantaneous velocity at the time of the middle of the period in a linear motion with uniform velocity.