experimental name: measuring the energy of peanut seeds

experimental purpose: 1. learn to use scientific inquiry methods, be able to ask questions and design experiments. 2. Qualitative and quantitative analysis of energy in food is made through experimental determination. Experimental principle: 1. Determine the energy in food by measuring the amount of heat released by food combustion. 2.1ml of water needs to absorb 4.2 joules of heat for every 1℃ increase. Experimental equipment and medicines:

peanuts, matches, dissecting needles, conical bottles, thermometers, test tube clamps, measuring cylinders and water. Experimental steps:

1. Inject 3ml of water into the conical bottle and fix it on the iron stand. 2. Install an experimental device to measure the initial temperature of water with a thermometer.

3. Weigh the mass of a dried peanut seed and light it on the flame. 4. Put the freshly burned peanut seeds at the bottom of the conical flask as soon as possible. After this peanut seed is completely burned, measure the water temperature. Experimental process and conclusion:

The energy per gram of peanut seeds is 5124 coke

Changes of steamed bread in oral cavity

Experimental name: Changes of steamed bread in oral cavity

Experimental purpose: To prove that starch digestion is related to chewing of teeth, tongue stirring and saliva. Experimental principle: 1. Salivary amylase can catalyze the decomposition of starch into maltose. 2. Iodine and starch turn blue. Experimental equipment and medicines:

Fresh steamed bread, saliva, test tube, iodine solution, beaker, measuring cylinder, hot water, thermometer and other experimental steps:

1. Take fresh steamed bread, cut it into three ABC pieces with the same size, and finely chop and mix Block A and Block B with a knife, while Block C will not be treated.

2. Rinse your mouth with cold boiled water, with a piece of sterilized cotton wool in your mouth. After one minute, take out the cotton wool with clean tweezers and squeeze the saliva in the cotton wool into a small beaker.

3. Take three clean test tubes, number them with (1), (2) and (3) respectively, and do the following treatment.

experimental process and conclusion:

design a lunch menu for parents

experimental name: design a lunch menu for parents

experimental purpose: by designing a lunch menu with reasonable nutrition for parents, try to use the knowledge about reasonable nutrition and care about the diet of the elders. Experimental principle: Dietary Guide for China Residents

Experimental equipment and medicines: paper, pens, vegetables, condiments and kitchen supplies.

experimental steps: (For example, it can be designed according to the nutritional dietary guidelines on page 34 of the book, and the nutritional ingredients are on page 38-39)

1. Food types: cereals, rhizomes, bean products, aquatic products, agricultural and sideline products, cereals, milk and oils.

2. Nutritional components: (1) stir-fried celery and stir-fried dried beancurd (because celery contains a lot of vitamins and crude fiber, and dried beancurd contains protein)

(2) steamed fish (grass carp, any other fish) has solid alcohol and low fat.

(3) Tomato and egg soup. Tomatoes are rich in vitamins, especially vitamin C.

simulating the movement of diaphragm

experimental name: simulating the movement of diaphragm

experimental purpose: to explore the relationship between the changes of thoracic cavity and breathing.

experimental principle: the glass cover simulates the thorax, the glass tube simulates the trachea and bronchus, the balloon simulates the lung, and the rubber membrane simulates the diaphragm. Through the change of air pressure, the relationship between the change of thorax and breathing is explored. Experimental equipment and drugs:

glass cover, glass tube, balloon and rubber film. Experimental steps:

1. Assemble the experimental device as required.

2. Hold the model in one hand, push the rubber film up with the other hand, and then relax the rubber film. 3. Observe the relationship between the change of balloon volume and the change of rubber film position. Experimental process and conclusion: < P > The balloon retracts when the rubber film is pushed up by hand; When you relax, the balloon expands. Model paper 2:

Exploring the hydrolysis of starch and sucrose by amylase

1. Experimental purpose

1. Initially learn to explore the method of enzyme catalyzing specific chemical reactions.

2. Explore whether amylase can only catalyze specific chemical reactions.

ii. experimental principle

both starch and sucrose are non-reducing sugars, which can be hydrolyzed into reducing sugars under the catalysis of enzymes, and the reducing sugars can undergo redox reaction with Fehlin reagent to generate brick-red cuprous oxide precipitate.

Using amylase to catalyze starch solution and sucrose solution respectively, and then using Felling reagent to identify whether there is reducing sugar in the solution, we can see whether amylase can catalyze these two chemical reactions.

iii. Materials and appliances

dropper, test tube, match, test tube rack, thermometer, tripod, asbestos net, alcohol lamp, beaker, fresh amylase solution with mass fraction of 2%, soluble starch solution with mass fraction of 3%, sucrose solution with mass fraction of 3%, and Feynin reagent

iv. Experimental process (see book P47). Chemical experiment report? Biological experiment report? Experimental report format? Template of experimental report

V. Discussion

1. The prepared soluble starch solution must be completely cooled before use. Why?

2. when two test tubes are kept warm, why should they be kept at about 6℃ (below 5℃ or above 75℃)?

3. If the No.2 test tube also produces brick red precipitate, what may be the causes? Model essay 3 of the first grade experiment report:

? Buoyancy disappears? In order to

make the following small test equipment

find a container with a flat bottom, let a candle head cling to the bottom of the container, and then pour water into the container, so that the candle head will not float; Gently tilt the candle head down and it will float at once.

it can be seen that when the object is in close contact with the bottom of the container, there is no liquid infiltration between the two contact surfaces, and the lower surface of the object is no longer subjected to the upward pressure of the liquid, so the liquid loses its upward supporting force on it, and the buoyancy naturally disappears.

now, can you put forward some measures to help the submarine get out of trouble?

　? How is buoyancy generated? Students, right? Buoyancy is the difference between the upward pressure and downward pressure of liquid on an object? This conclusion is understandable, but it is hard to believe, so it is the key to overcome this difficulty to do the experiment of buoyancy disappearance. Here are two simple methods.

[Method 1]

Equipment: a glass funnel with appropriate size (available in the chemistry laboratory), a ping-pong ball and a cup of red water.

Steps:

(1) Push the ping-pong ball into the water intentionally, and the ping-pong ball will float quickly after letting go.

(2) Hold the funnel with your hands (the bell mouth is upward, and the funnel handle is sandwiched between the middle finger and the ring finger), put the ping-pong ball in it, hold the ping-pong ball with your thumb, pour the water into the funnel, and release your thumb to see that the ping-pong ball does not float. (At this time, there is water flowing downwards from the lower mouth of the funnel handle, which is because the ping-pong ball and the funnel are not tightly closed.).

(3) Block the water outlet with your fingers, and it can be seen that the water level in the funnel handle rises gradually. When the water level rises to the table tennis ball, the table tennis ball immediately floats. (If the water comes out of the lower mouth of the funnel handle too quickly, you can put a circle of cotton at the contact between the table tennis ball and the funnel, so that you can calmly observe the rising of water in the funnel handle. )

[Method 2]

Equipment: a transparent flat-bottomed plastic bucket (with a depth of about 1cm and a larger diameter for easy operation), a wooden block with a basically flat bottom (such as chess, building blocks, thermos bottle stoppers, etc.), a chopstick and a cup of water.

making a small hole barrel: burn an iron skewer on an alcohol lamp, make a small hole in the center of the bottom of the plastic barrel with a hole diameter of about 1cm, and smooth the hole edge with sandpaper to form a small hole barrel.

Steps:

(1) Press the wooden block into the water intentionally, and the wooden block will float quickly after letting go.

(2) Put the flat side of the wood block into the small hole bucket and cover the small hole, hold the wood block with chopsticks and pour water into the bucket. Remove the chopsticks, and it can be seen that the wooden block does not float. At this time, there is water dripping down at the small hole, because the contact surface between the wood block and the bucket is not very close.

(3) Block the hole with your fingers, and the block will immediately float.

the above two examples skillfully use the fact that the surface of an object can't be absolutely smooth in practice? Small hole leakage? So that water does not remain under the object, so that the object loses the upward pressure of the liquid, and thus loses its buoyancy. As a result, the table tennis and wooden blocks that should have floated on the water are firmly nailed to the bottom of the water, which cannot but make the students gasp in admiration. Then step (3) magically reappears buoyancy, which makes students feel high and eager to try.

experimental report of series circuit and parallel circuit

1. experimental purpose: to master the connection mode of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

second, experimental equipment: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3. Steps: 1. Form a series circuit

A. According to the circuit diagram in Figure 1-1, first connect the circuit elements in Figure 1-2 into a physical circuit diagram with a pencil in the order in the circuit diagram (the positions of the elements are required to be fixed and the wires cannot cross).

B. Connect the circuit according to the circuit diagram in Figure 1-1, turn on and off the switch, and observe whether the switch controls two light bulbs at the same time or only one light bulb.

Observation result: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. Then connect it between L2 and the negative electrode of the battery, and repeat the experiment B. Observe whether the control function of the switch has changed. And draw the corresponding circuit diagrams respectively.

Circuit diagram

Observation result: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ________________. 2. Form a parallel circuit

A. Draw a parallel circuit diagram composed of two electric lamps L1 and L2, requiring that switch S be connected to the main road, switches S1 and S2 be connected to two branches respectively, and connect the physical circuit diagram of 1-3

with a pencil according to the circuit diagram.

Circuit diagram < Then carry out the following experiments and observations:

a. Turn on S1 and S2, then turn on or off the trunk switch S, and observe which light bulb is controlled by the switch S.

Observation results: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Turn off or turn off the trunk switch S1, and observe which light bulb the switch S1 controls. Observation result: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Observe which light bulb the switch S2 controls.

Observation result: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ If the position of the switch changes, its control function is _ _ _ _ _ _ _. < P > 2. The switch in the parallel circuit trunk controls _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; The switch in the branch can only control _ _ _ _ _ _ _ _ _ _ _ electrical appliances.