It is very simple to find a scientific research report for the first year of junior high school, and

Science**: How to judge a person's height based on the length of their footprints?

Investigation Experimenter:

When solving crimes, the police often deduce the height of criminals based on the length of human footprints. Archaeologists also determine the height of people of that era based on the length of ancient human footprints. Now, let's work together.

1. Ask the question: [What is the relationship between human foot length and height?] 】

2. Establish a hypothesis: [It is possible that the taller and taller the person, the longer the feet, and the ratio of height to foot length is about 6-7].

3. Design the experimental plan: [Use a tape measure to collect the foot length and height of a dozen students, and then calculate the ratio between the two].

4. Collect factual evidence (as follows):

Subject: Height, cm, Foot length, cm, Proportion, Gender.

Liu Yichen 131 20 female.

Liu Chunlian 145 21 female.

Xiao Rong 150 24 female.

Liu Houyu 167 24 male.

Liu Xiaoping 172 male.

5. Inspection and evaluation: [Based on the factual evidence collected, I have come to the conclusion that the person being tested.

's height is about twice the length of a foot, and my assumption is correct.

6. Cooperation and exchange: [After precise calculations, scientists have calculated that the height of a person is about a foot.

times the length, but the height ratio of people in different places is also different, for example, the height of northeasterners is times the length of their feet, and the height of southerners is doubled; The people of Shanghai are doubled, while the people of Shaanxi are doubled, and the people of Chongqing are doubled, which shows that the differences between the east, west, north and south of China are caused by the latitude and diet. 】

It was a physics experiment in the second year of junior high school.

1.It should be the cause of habitual grinding, rear-end collisions often occur, and the friction of the tire can be appropriately increased to prevent rear-end collisions.

2.Cupping is heated to make the air in the tank expand and shrink when it is cooled, so that the can can be sucked on the back.

3.Question 3 seems a bit difficult. Han Zheng.

Huh. Ningbo 15th Middle School New Junior High School Second Job,

Question: Can sunlight help plants heal wounds, but can moonshine too?

Plants cannot grow without the sun, because sunlight can help plants grow normally. According to the data, sunlight can help plants heal wounds and make plants grow better. As we all know, the moon does not emit light, and its light is obtained by reflecting the sun's light.

If the light of the sun helps plants heal wounds, then the light of the moon also helps plants heal wounds.

Small experiment: two garlic with a similar degree of development (garlic grows fast and has strong vitality), and at the same time plucks off the same number of leaves, one shines on the sun and the moon, and the other shines only on the sun. After observing for several weeks, it was found that the wound of garlic that was exposed to both sunlight and moonlight healed quickly and had begun to grow new leaves, while the wound of garlic that only shone sunlight also healed, but there was a large scar and no new leaves grew.

Moonshine helps the plant to heal wounds and grow new leaves.