- 1- Construction of a homemade electromagnet
- materials
- Process
- Experiment
- Points to verify
- 2- Convection current
- Materials:
- Process
- Experiment
- Points to verify
- 3- Refraction of light
- materials
- Process
- Experiment A
- Points to verify
- Experiment B
- Points to verify
- 4- See the germs in the mouth with a home microscope
- Materials:
- Process
- Experiment
- Points to verify
- 5- Lemon battery
- materials
- Process
- Points to verify
- 6- Home pH indicator
- Materials:
- Process
- Points to verify
- Try different substances
- 7- DNA extraction and observation
- materials
- Process
- Points to verify
- 9- Homemade capacitor (Leyden bottle)
- materials
- Process
- Points to verify
- Alternative procedure
- 10- Newton's second law
- materials
- Process
- Points to verify
- References
Today I bring you a list of science experiments for high school with which you can learn concepts of physics, chemistry and biology. Doing scientific experiments means visualizing phenomena and corroborating theories; they also represent an opportunity to become familiar with the scientific method.
All the experiments are easy to perform and use equipment and materials of daily use. For the interpretation of the results, at least one level of secondary education student is required.
Figure 1. Experimentation is a fundamental part of Science. Source: Pixabay.
1- Construction of a homemade electromagnet
materials
-Alkaline 1.5V batteries (2 or 3 batteries)
-Battery holder
-Thin and enameled (varnished) copper wire for windings.
-Steel screws.
-Iron nails.
Figure 2. Materials for the construction of an electromagnet. Source: youtube.
Process
-Wind the enameled copper wire around one of the steel screws.
-With a cutter or a knife, scrape the varnish from the free ends of the copper cable that was wound on the steel screw.
-Place the batteries in the battery holder and connect the ends to the terminals of the battery holder.
Experiment
- Bring the tip of the screw closer to the nails and observe that they are attracted.
-Note that when disconnecting the cable from the winding, the electromagnet stops working.
-Increase the power of the magnet by connecting more batteries in series.
-Increase the magnetic field of the electromagnet by placing more winding turns.
Points to verify
-Magnetic force is greater the more current.
-With the same current the magnetic force increases if the number of turns increases.
-With the same number of turns (each turn is a turn) and current, the power of the electromagnet increases if the turns are tightened or approach each other.
-If the screw is unscrewed and the spiral is left alone, the magnetic effect continues but is substantially weakened.
2- Convection current
Materials:
- A sheet of paper
- A piece of thread
- A candle
- Lighter
Process
-On the sheet of paper draw a spiral.
-Cut out and make a small hole in the center of the spiral.
- Pass the piece of thread through the spiral. Tie a knot at the end of the thread so that it does not come off the spiral.
-Lift the spiral with the thread, so that it forms a helix.
Experiment
-Turn on the candle.
-Place the paper helicoid already suspended by the thread, on the lit candle.
Caution: the paper propeller must be away from the flame, so that it does not ignite.
Figure 3. Paper helix rotating due to the updraft of thermal convection. Source: youtube.
Points to verify
-Note that the helicoid begins to rotate. The reason is the updraft of hot air. Hot air rises because it is lighter than cold air.
-Increase the turning speed by placing two candles instead of one.
3- Refraction of light
materials
-A glass tumbler
-A jug of water
-A coin
-A pencil
Process
-Place the coin on the table.
-Then put the glass on the coin.
Experiment A
-Look at the coin under the glass, from an oblique position and from above.
Now pour water into the glass and repeat the observation from a side angle and from above.
Points to verify
-When the glass is empty the coin can be seen through the glass both from the side and from above. But if the glass is filled with water while we look at the coin from a 45º angle, we notice that it suddenly disappears from our sight.
-If we look directly from above we notice that the coin is still there. The phenomenon is explained because light is deflected when it passes from one medium to another.
-When water is added at the interface between the glass and the water, there is a deviation of the light grazing to the bottom of the glass and therefore the coin is not displayed.
Experiment B
-Now place the pencil in the glass cup with water so that one part is submerged and the other in the air.
Points to verify
-Observe the pencil from the side: it seems that it has been broken. Again the explanation of this phenomenon is the deviation suffered by a light ray when it passes from one medium to another.
Figure 4. Refraction of a semi-submerged pencil. Source: Wikimedia Commons.
4- See the germs in the mouth with a home microscope
Materials:
- A couple of glasses or glasses
- A syringe without the needle
- A sewing needle
- A laser pointer
- Scotch tape
Process
-We fill the syringe with water.
-We support the fins of the syringe to the walls of the two vessels that will act as columns and support for the syringe.
-Squeeze the syringe gently until a drop forms at the tip that is held by surface tension at the edges of the tip of the syringe.
-Pass the adhesive tape around the laser button so that it remains on.
-Aim the laser light at the drop and see the projection on the wall.
Experiment
-Rub the sewing needle carefully, without pinching, on the inside wall of the mouth.
-Touch with the tip of the needle previously rubbed in the mouth, the drop of water at the tip of the syringe.
-Observe the projection and notice the differences.
Figure 5. Germs from the mouth amplified and projected with laser light. Source: youtube.
Points to verify
-In the projection of laser light on the wall, the germs in the mouth are amplified.
-You can repeat the experiment, using water from a vase for the syringe, which may contain microorganisms such as paramecium and amoeba.
5- Lemon battery
materials
-Lemons
-Copper coins, or bare copper wire.
-Galvanized screws
-Voltmeter
-Cables
-Cable alligator clips
Process
-A lemon is taken and a piggy-style slot is made to insert the copper coin.
-On the opposite side the galvanized screw is screwed and inserted.
-The alligator clips are adapted and connected to the voltmeter cables.
-The alligator of the positive is connected to the copper coin.
-The negative alligator of the voltmeter connects to the galvanized screw.
Figure 6. Lemon battery and voltmeter. Source: youtube.
Points to verify
-Measure the voltage produced by the lemon battery. This voltage should be a little less than one volt.
-Build a second and third lemon battery, connect in series and check the voltage.
-Try to light a flashlight bulb. Try one or more lemon stacks in series.
-Now connect the lemon stacks in parallel. Check the voltage.
-Apply the parallel combination of lemon batteries to the flashlight bulb.
-Draw your conclusions.
6- Home pH indicator
Materials:
-Glass containers
-Distilled water
-Purple cabbage
-Filter paper
-Cooking pot
-Kitchen
-Glass container
Process
-Cut the purple cabbage.
-Cook the cabbage pieces in a pot for 10 minutes.
-Remove from the stove and let it rest until it cools down.
-Strain or filter into a clean container, preferably glass.
-Save the liquid extracted from the purple cabbage, which will serve as a pH indicator.
Points to verify
-The pH indicator works like this:
i) For an acid substance it turns from pink to red.
ii) If it is a neutral substance, it maintains its dark blue color.
iii) When tested on alkaline or basic substance, it turns green in color.
Try different substances
-Acids that are safe to handle: vinegar and lemon juice.
-Cola soda
-Tomato
-Human urine
-Pure water
-Saliva
-Salt water or sea water
-Sodium bicarbonate.
-Toothpaste
-Milk of magnesia
-Homemade bleach or ammonia (use plastic gloves, do not touch with hands or clothing)
-To do the tests it is useful to make some strips of absorbent paper that are impregnated with the pH indicator.
-Note in a notebook, classify in descending order, from the most acidic substances to the most alkaline.
Caution
Very strong acids and bases can cause burns and irritation to the skin, mucous membranes and eyes. It is advisable to wear plastic gloves throughout the experiment, especially if you have sensitive skin.
7- DNA extraction and observation
materials
-Chicken liver
-Liquid dishwashing detergent
-Meat tenderizing enzymes, such as papaya juice or powdered meat tenderizer.
-Ethyl alcohol without dye
-Blender
-Glass bottle
-Fine strainer
-Beaker with graduations
-Elongated glass container or test tube.
Process
-Place raw chicken liver in the blender glass.
-Add a little water and blend until you get a creamy paste.
-Pour the liquefied liver through a strainer into the graduated beaker.
-Measure the amount of smoothie in the container.
-It is poured dishwasher, in a measure equal to a quarter of measure of the liver smoothie.
-Stir with a spoon.
-Add a tablespoon of meat tenderizing enzymes or papaya juice and stir for five minutes.
-Stir gently, so that the DNA chains do not break.
-The mixture is poured into an elongated glass container type test tube.
-Tilt the test tube and carefully pour the alcohol so that it does not mix with the liquid at the bottom.
Points to verify
-After a few minutes, you can see some white filaments inside the alcohol, coming from the mixture of liver, detergent and enzymes. Those strands are the chicken's DNA.
9- Homemade capacitor (Leyden bottle)
materials
-Glass or plastic jar, such as mayonnaise.
-Plastic insulating cap pierced through which a rigid wire or cable will pass.
-Rectangular strips of kitchen aluminum foil to cover, stick or adhere the outside and inside of the jar.
-A flexible cable without insulation that is spliced to the inside of the rod so that it makes contact with the aluminum foil that covers the inside of the wall of the bottle
-It is important that the aluminum coating does not reach the edge of the bottle, it can be a little higher than half.
- Cable without insulation that will be attached to the outer aluminum sheet.
Note: Another version that avoids the work of placing the aluminum foil on the inside, consists of filling the bottle or jar with a solution of water and salt. which will act as an interior plate.
Process
-If you have an old television or monitor, whose screen is cathode ray you can use it to charge the bottle.
-Hold the bottle with one hand by the outer plate, while approaching and touching the screen with the cable that connects to the inner part.
-Then take the cable tied to the outside and bring it closer to the cable that comes from the inside of the bottle.
Points to verify
-Observe that when you bring the cable connected to the outside with the one that comes from the inside, a spark is produced, showing that the bottle has been electrically charged.
Alternative procedure
-If you do not have a suitable screen, you can load the Leyden bottle by holding it close to a woolen cloth that you have taken from the clothes dryer.
-Another option for the charging source is to take a piece of plastic tube (PVC) that has previously been sanded to remove the varnish. Rub the tube with a paper towel until it is sufficiently charged.
10- Newton's second law
materials
-Elevator
-Bath scale or weight
-Notebook
Process
-Take a bathroom weight to an elevator, stand on it and record the values that it marks during the up start, the descent start and during the time that it moves at constant speed.
Points to verify
-Now apply Newton's second law, for this draw a diagram of forces and solve for the acceleration of the elevator.
Figure 7. Free body diagram of boy in elevator. Source: F. Zapata.
-Calculate the accelerations of the elevator corresponding to each case.
References
- Easy Science. Volta stack. Recovered from: Cienciafacil.com
- ExpCaseros. 10 science projects. Recovered from: youtube.
- Experimenting. 5 homemade physics experiments. Recovered from: youtube.com
- DIY time. 10 home experiments. Recovered from: youtube.com
- Lifeder. Newton's second law: applications, experiments. Recovered from: lifeder.com
- Mobile Beta. How to make a homemade electromagnet. Recovered from: youtube.com