1. Create a colored shadow

Question: Are all shadows black? If not, what color is it? Can you make the shadow colorful? Why does the colorful world we usually see have colors?

Please design: let me have a colorful shadow.

Tip: Please refer to the three-color principle and analyze the conditions of shadow formation.

Recommended equipment: 3 lamps with masks, red, blue and yellow negatives, and a darkroom.

2. Homemade bicycle odometer

Problem: The car has an odometer. Can we also install odometers for bicycles? How to automatically record every rotation of bicycle wheels and convert it into kilometers? What method can be used to realize counting conveniently?

Please design: Convert the revolutions of bicycle wheels into kilometers by mechanical or electronic methods and record them.

Tip: Consider the relationship between bicycle rotation and mileage, sampling method and recording method.

Recommended equipment: reed switch, magnet, calculator, wire, etc.

3. Make a scale that can measure the density of liquid.

Question: The quality of some liquid commodities we usually encounter may be related to their density. How to measure the quality of liquid conveniently?

Please design: give you a steelyard, please add some small accessories, and design a convenient method for measuring liquid density.

Recommended equipment: scale

4. Design a solar cooker that is not affected by the change of sun position.

Problem: Solar energy is a kind of green renewable energy, but there is a trouble in heating things with solar cookers, that is, the angle of the sun relative to the solar cookers is constantly changing. Can you design a solar cooker with the same focus no matter where the sun is?

Please design: such as the title

Tip: Please refer to the properties of some surfaces in geometry.

Recommended equipment: small mirror (large quantity)

5. Design a family water saving scheme.

Question: We all know that water resources in China are very scarce, and it is everyone's responsibility to save water. As a family, what methods should be used to make more rational use of water resources?

Please design: the process of domestic water use, the details of water saving, and related devices.

6. Design the distribution and recycling scheme of community domestic garbage.

Problem: Human beings will produce a lot of domestic garbage in their daily life, some of which are toxic and pollute the environment (such as old batteries and waste fluorescent tubes), and some of which are good industrial raw materials (metal products, paper, plastics, etc.). ) after recycling. How to classify garbage conveniently and recycle the useful parts of toxic things for proper disposal?

Please design: design a separation device that can sort out one or more kinds of garbage by using different physical properties of various kinds of garbage.

7. Design an environmentally friendly home energy scheme with solar energy as the main energy source.

Q: We already know that there are many kinds of civil equipment using solar energy, such as solar water heaters and solar cells. Can a modern family live on solar energy alone?

Please design: I want to have a green family. I just want to use solar energy. Please design a home for me. I want to watch TV and use the computer. Anyway, I want to protect the environment and don't want to live a primitive life. Help me.

Tip: Solar energy can be directly used as a heat source and can be converted into electric energy storage at night and cloudy days, so you should design energy collection devices and energy storage devices and arrange houses and household appliances reasonably.

8. Design an automatic door closing device (no motor, no spring)

Question: Is this a test for you to automatically close the door? It's still about energy. What methods can we use to save some energy in opening and closing doors without springs?

9. Design a flashlight without battery by using LED consumption.

Problem: LED is a good thing, with high luminous efficiency and long life. You have seen flashlights that can emit light without batteries in the market, which contains many physical principles. Let's design one ourselves.

Tip: To convert kinetic energy into electric energy, it is best to have an energy storage device, so that the flashlight can light up for a while and there is a how bright.

10. How does the column of the crane rise and fall on the construction site? Please design a plan to adjust the height.

Second, analyze and think about the topic

1. How many experiments can be designed with balloons?

2. Analyze the reasons for the failure of several perpetual motion machines with physical knowledge?

Question: Have you all heard of perpetual motion machines? Please find some design drawings of perpetual motion machines and point out the reasons why they can't move forever with the knowledge of physics we have learned.

3. Try to use physical methods to analyze and estimate whether the Great Wall can be seen by naked eyes at the altitude of 300-400 kilometers of the spacecraft.

4. Is there any feasible way to make the Great Wall easily visible to the naked eye at a height of about 350 kilometers from the spacecraft?

5. Try simple experimental equipment to find out the relationship between the discharge of general electronic circuits and air pressure and voltage. (For safety, only a small current is needed, and the voltage does not exceed 1000 volts. )

6. On the surface of the moon, can modern guns or cannons be used to launch the moon's "bullet or cannonball satellite"?

7. How many forms of heat exchange are there? How do two objects with different temperatures exchange heat in vacuum?

8. Why can sailboats sail forward with sails against the wind?

9. The lights that illuminate the stairs can be turned on and off upstairs and downstairs. How is the circuit made?

10, what are the characteristics of laser compared with ordinary light?

1 1. What kind of microscope can "see" atoms? Why?

12 what is antimatter? (Analysis article)

13, try to compare aircraft engines with rockets and their flight principles.

14. why don't astronauts turn over when they sleep in a spaceship flying around the earth?

Third, expand and improve the topic.

1, in planets of the solar system's satellite system, is there a situation that satisfies Titius-Bode's law?

2. Summarize the methods and achievements of detecting extrasolar planetary systems so far.

3. Discussion on the feasible methods to avoid asteroids hitting the earth.

4. Calculate the limit magnitude of celestial bodies that can be detected by a telescope with a certain caliber during the day.