Study Material

# Physics experiments easy to do (Primary to University)

We explain the Physics experiments easy to do from Primary to University level. The physics experiments are important for the development of scientific curiosity at all ages.Â There are numerous experiments that, due to their importance, have made history and changed the course of science, such as those of Galileo Galilei.

Here are some simple experiments that demonstrate how physics continually works on the simplest things in everyday life.Â You don’t have to use expensive instruments to have fun figuring out how nature works.

All these experiments are easy to perform and with harmless materials that are not expensive, however in the case of younger children, they should always be carried out under the supervision of adults.

## Physics experiments for kids

To make children familiarize themselves with science, nothing better than colored balloons.Â The following experiments refer to static electricity.

### Electrified balloons

#### Materials easy physics experiments

• Rubber balloons.
• Wool jacket or sweater.
• A room with smooth walls.

#### Process

• Inflate the balloons and knot the end.
• Rub each balloon a little with the fabric of the jacket or sweater.Â It also works if rubbed into your hair.
• Now you have to bring the rubbed balloon to a smooth wall, without pressing it, and gently release it.

#### What’s going on?

What happens is that the balloons stick to the wall as if they had glue. They can stick there for quite some time, but for the experiment to work well, the wall has to be fairly smooth and there should be little humidity in the environment.

#### Explanation easy physics experiments

AllÂ matterÂ is composed of atoms and inside these there are both positive (protons) and negative (electrons) electric charges.Â Normally matter is neutral, that is, positive and negative charges are present in equal amounts.

However, the hair or wool easily give up their electrons, which are accepted by the material of the balloon and cause it to be electrified with a negative charge.

For its part, the wall also has electrons.Â When the electrons of the balloon approach those of the wall, they are repelled and move away from the surface, which is positively charged.

Between electrically charged objects, forces develop that are attractive if the charges are of different sign, and repulsive if the charges have the same sign. That is why the balloon remains attached to the surface of the wall. easy physics experiments

Over time, the excess electrons escape to the earth and the objects regain their neutrality, then gravity has no one to counteract it and the balloon falls.

### Separate the salt from the pepper

#### Materials

• Rubber balloon.
• Wool jacket or sweater.
• A plate with well mixed salt and black pepper.
• Another plate with pieces of paper (paper or confetti).

#### Process easy physics experiments

• Inflate the balloon and tie a knot at the end.
• The balloon is rubbed gently with the hair or with the wool garment.
• Now pass the rubbed surface of the balloon over the plate with salt and pepper.
• Pass another previously rubbed balloon over the confetti plate.

#### What’s going on?

It is observed that the peppercorns and confetti adhere to the surface of the balloon and the salt remains on the plate.

#### Explanation easy physics experiments

As explained in the previous experiment, the atoms that make up matter contain electrons and protons in equal amounts, making matter neutral under normal circumstances.

Electrons have a negative electric charge and protons have a positive electric charge, and what is observed in nature is that charges of the same sign repel and those of a different sign attract. easy physics experiments

However, there are materials capable of easily giving up some of their electrons, while others accept them with equal ease.

Hair and wool belong to the category of materials that donate electrons, while the plastic in balloons accepts them.Â By rubbing both materials, the electrons detach from the hair or wool and end up in the balloon, which is thus electrified.

When the balloon with its excess electrons approaches the plate with salt and pepper, the electrons of this try to get as far away as possible from the balloon and the surface of the grain closest to it is left with an electron deficit, so it is attracted.

This separation of charges gives rise to a polarization of the material, in this case the pepper, although it is still neutral.

Something similar happens with the paper of the confetti, but with the salt it is different, it does not adhere.Â What happens is that the salt is heavier and although the charges do separate, as happens with pepper and confetti, the electrostatic attraction is not enough to overcome theÂ weightÂ .

### Checking heat conduction

#### Materials easy physics experiments

• A sheet of white paper.
• A sheet of black paper.
• Running water.
• Two identical glasses.
• Scotch tape.
• A general purpose thermometer.
• Sunlight.

#### Process easy physics experiments

• Completely wrap the glasses, one of them with the white sheet and the other with the black sheet, taking care to leave excess paper to cover the top.
• Fill both glasses with the same amount of water and measure the temperature of the water, noting its value.
• Now cover the glasses with the excess paper around the edges and secure with adhesive tape.
• Now place both glasses under the Sun, on a cement floor and wait 30 minutes.
• Once the time has elapsed, uncover the glasses and measure the temperature again.

#### What’s going on?

The water in the glass covered with black paper is hotter than the other glass. easy physics experiments

#### Explanation

The glass covered with the black paper absorbed more heat from theÂ SunÂ and also allowed it to conserve it more, unlike the white paper, which reflected part of the solar radiation to the surroundings.

Although this does not necessarily mean that it is better to wear white during the summer or in very hot places, because it also depends on whether or not the breeze blows. It must be taken into account that the human body produces heat and when wearing white, part of that heat is reflected against the fabric and cannot escape. easy physics experiments

On the other hand, dark fabrics absorb it, that is why many desert inhabitants wear dark and loose clothes, very important for the air to circulate and the convection currents to make it feel cooler.

#### Materials easy physics experiments

• A long iron nail.
• A 9 volt square battery.
• One meter of varnished copper wire.
• A plate or box with pins.
• Metal clips or hooks to hold paper.

#### Process

• Carefully wrap a part of the wire around the nail, making about 10 turns and at each free end of the wire place a paper clip.
• Connect each clip to the battery poles.
• Now approach the tip of the nail to the plate with pins, observe and then remove.
• Make another 10 turns of wire around the nail and repeat the previous step, noting if there is any change in the behavior of the pins.

#### What’s going on?

The nail became a magnet capable of attracting pins, and the magnetic effect isÂ enhancedÂ by the number of turns of wire wound on the nail, so more pins are attracted when there are 20 turns than when there are 10 turns.

#### Explanation

Associated with moving charges is the magnetic effect, whereby the wires that carry current produce a magnetic field.Â Certain materials such as iron and steel have a good magnetic response, which means that they are attracted to magnets.

The battery does the work necessary to start the charge carriers in the copper of the wire, that is, it creates an electrical current.Â And this in turn produces the magnetic effect that attracts metallic objects.Â This effect is proportional to the number of turns of the wire winding, the more turns, the stronger the magnetic field and the more pins are attracted.

### Sound propagation in a solid medium

#### Materials

• A piece of soft string about 1 meter long.
• A heavy metal spoon.

#### Process easy physics experiments

• Tie the spoon with the string and hold the ends of the string between the thumb and forefinger of each hand.
• Bring the ends of the string to the ears, taking care to press the string well to the ear with the help of the thumb, the spoon should be hanging.
• Now you hit the edge of a table with the spoon and listen carefully.

#### What’s going on? easy physics experiments

A sound similar to that of a church bell is heard, but low in tone.

#### Explanation easy physics experiments

Sound waves propagate better and faster in solids than in air, this is because solids are denser and the disturbance has more particles to oscillate.Â So the sound travels through the string and is heard louder than the waves that propagate in air.

The listener’s skull also acts as a sounding board so that the sound is heard more intensely.Â This is what happens when you speak by putting your hands on your ears, the sound of your own voice is heard louder and also deeper.

The experiment can be repeated by trying other materials and observing the differences.

## Physics experiments for secondary school (10-15 years)

At these ages, children have already seen numerous physical phenomena in their science classes.Â Here are two easy experiments to familiarize yourself with forces and static equilibrium, another to learn about the different types of waves, and finally one to learn about corrective lenses.

### Steel can float on water easy physics experiments

#### Materials easy physics experiments

• A wide glass container.
• Running water.
• Steel needle of the kind used for sewing.
• Filter paper.
• Wooden chopsticks.

#### Process

• Fill the container with water up to about Â¾ parts.
• Aside put the needle on the filter paper and put it on the surface of the water.
• Go carefully sinking the paper with the help of the wooden sticks.

#### What’s going on?

If the procedure is followed carefully, avoiding that the tip sinks into the surface of the water, it is observed that the steel needle remains floating on the water.Â This is not what is expected, as a dense metallic object immediately sinks.

#### Explanation

An object whoseÂ densityÂ exceeds that of water sinks in it and steel is almost 8 times as dense.Â Although the liquid exerts an upward force called thrust, it cannot fully counteract the weight, so there must be another force to help.

This force is calledÂ surface tensionÂ , and it comes from the attraction that exists between all the water molecules.Â A water molecule below the surface receives attractive forces from all its neighbors: above, below, and to the sides.Â The net effect of all of them is nil.

However, a water molecule that is on the free surface receives forces from the molecules that are below and to the sides, but none above.Â In this way, a downward resultant force is created, which creates a kind of very thin film, capable of holding the pin or steel needle.

Care must be taken that the tip of the needle does not puncture this film, otherwise the needle will sink to the bottom.

### Different types of waves

#### Materials

• A flat table of sufficient length.
• Table screw.
• A flexible coil spring of about 5 cm in diameter, called aÂ slinkyÂ .

#### Process

• Fix one of the ends of the spring to the end of the table, ask a colleague to hold it or simply hold it by hand, in any case the spring must be horizontal.
• Now the other end of the spring is taken, it is stretched and a few turns are compressed, to give a brief impulse in a direction parallel to the axis of the spring.
• Observe what happens.
• You can also try giving it a brief shake by hand, perpendicular to the axis of the spring.
• Observe again what happens.

#### What’s going on?

When a parallel impulse is given to the spring, it is observed that a group of turns tightens and expands alternately, traveling along the spring to the fixed end.Â If the impulse was sufficient the disturbance returns back and finally disappears.

If the spring is given a transverse impulse, a ripple is produced that travels to the other end and that also disappears.

#### Explanation

In this simple experiment, two kinds of waves are observed, depending on the oscillation of the material.Â There are theÂ longitudinal wavesÂ , which consist of alternate compressions and expansions of the coils of the spring.Â In them the disturbance and oscillation are found along the axis of the spring.

And there is the disturbance in the form of a ripple, when the spring is urged perpendicular to its axis.Â In this case the oscillation is from top to bottom, perpendicular to the oscillation, therefore these waves are calledÂ transverse wavesÂ .

It is important to note that the coils oscillate as the disturbance propagates through the spring and that is the same as happens with mechanical waves: there is no net transport of matter, but it is the disturbance that travels, carrying energy through the material.

In nature, longitudinal waves such as sound are produced, which consist of alternative compressions and expansions of air molecules, and there are transverse waves such as light and waves that are produced in the strings of musical instruments.

### Corrective lenses

#### Materials

• Various corrective glasses.
• Powerful flashlight, it can be the mobile or led light.
• A screen on the smooth wall.

#### Process

• Turn on the flashlight and point it directly at the screen, inserting the glasses to be analyzed.

#### What’s going on?

You see the shadow of the glasses of the glasses on the screen.Â But depending on whether they are corrective lenses for myopia, hyperopia or presbyopia, this shade will be different.

When they are myopia corrective lenses, the dark shadow of the lens is observed and a faint halo outside the frame.Â On the other hand, glasses for hyperopia and presbyopia show a luminous point in the center.

#### Explanation

The lenses used to correct these refractive problems in the eye are different.Â Divergent lenses are used for myopia, which, as their name indicates, extend the rays of light that come from the flashlight.

On the other hand, the lenses to correct hyperopia are convergent lenses, which means that they gather the rays of light at a point and therefore the center of the lens appears illuminated.

### The center of gravity of a flat sheet

#### Materials

• Cardboard, plastic or wood sheet of various shapes.
• A couple of nails.
• Universal support.
• A good size nut.
• Graphite pencil.

#### Process

• With the nut and the thread a plumb line is made that is used to correctly determine the vertical.
• One of the sheets is pierced with the help of a nail, if it is a triangular sheet, for example, the perforation is made near one of the vertices.
• Now the sheet is suspended through the hole made in the previous step, using a nail in the wall or a universal support, if you do not want to pierce the wall.
• The plumb bob is suspended from the same point to indicate the vertical, usually the plumb bob oscillates a little.Â When the whole system stabilizes, mark the vertical direction with the pencil on the cardboard.

• Then the sheet is taken and the indicated vertical is drawn with a pencil and ruler.
• The sheet is pierced again at another point near another vertex and the procedure of suspending it is repeated along with the plumb line, drawing a new vertical.Â The point of intersection of both lines is the center of gravity of the sheet.
• Try differently shaped sheets, even irregular ones.

#### What’s going on?

Each time the sheet is suspended and released, it oscillates briefly until it reaches the stable equilibrium position, where it remains if not disturbed.

#### Explanation

Bodies tend to remain in stable equilibrium because it is the state with the lowest potential energy.

For a body suspended from a point, stable equilibrium is achieved when this point is above the center of gravity, the point where weight can be considered applied.

In a regular geometric figure, the center of gravity coincides with its geometric center, as long as the density of the material is homogeneous, but if the figure is irregular, one way to find its center of gravity is through the experiment described.

### Balancing a flat sheet

#### Materials

• Sheets of cardboard, plastic or wood, to which the center of gravity has previously been determined (see the previous experiment).
• A pin or a long thin nail.

#### Process

• Place the sheet on the tip of the pin or nail, resting it on different points.

#### What’s going on?

It is observed that the sheet is kept in equilibrium only when it is supported on the center of gravity.Â When you try to support the sheet on any other point, it turns over immediately.

#### Explanation

If the line of action of the weight passes through the nail or pin that holds the sheet, it remains in balance, but if not, the distance causes the weight to cause an unbalanced torque, which tends to overturn the sheet.

### A battery made of lemon

#### Materials

• Lemons with plenty of juice.
• Copper wire or toothed clamp cables (alligator type).
• An iron or copper nail, or alternatively a copper coin.
• A galvanized zinc screw.
• A digital multimeter.
• An exact.
• AÂ smallÂ ledÂ bulbÂ (low voltage).

#### Process

• With the exact one, carefully make two small cuts at each end of the lemon
• Insert the screw on one side into the lemon and the copper coin (or the iron nail) on the other, these will be the battery electrodes.
• Connect the voltmeter, to do this place the central indicator of the instrument in the position to measure direct voltage and one end on the coin and the other on the screw.

#### What’s going on?

The voltmeter indicates small voltage, usually less than 1 volt.Â If the display of the device shows a negative sign it means that the polarity is reversed, simply connect the cables backwards.

The current generated is also small, around 0.1 mA, however it is necessary to make sure not to touch the two electrodes at the same time, so that the circuit is not closed.

The values â€‹â€‹change depending on how acidic the lemons are and also on the metals that are used as electrodes.Â If instead of using zinc magnesium is used, the voltage obtained increases.

Placing several lemons in series can obtain a battery of 3 volts or more, to be checked with the voltmeter.Â Wire or alligator-type cables are used to make the connection.

The led bulb needs more voltage than a single lemon battery to turn on, so you have to put several batteries in series (between 3 and 5 lemons are usually enough), connecting the ends with copper wire or tweezers.Â The light serves as a witness to the passage of the generated current.

#### Explanation

Inside the fruit and thanks to the contact of the ascorbic acid in the juice with the metals, which act as electrodes, chemical reactions take place.Â These reactions generate electrons that go from the zinc to the copper, passing through the interior of the lemon and this movement of charges constitutes an electric current when the electrodes are joined by the cables.

## Physics experiments for high school (15-18 years old)

At this level, students already know the equations that govern many physical phenomena.Â The periscope experiment helps them become familiar with optics and requires some manual dexterity.

With the second experiment they can visualize a field, in this case a magnetic one.Â The field concept helps to visualize and describe the fundamental interactions of Physics.

### Homemade periscope easy physics experiments

The periscope is a simple optical instrument used to see above the heads of the crowd or above the surface of the water.Â It can also be used to look under the bed and in general to visualize things that are not at eye level.

#### Materials

• 2 flat mirrors like the ones that come in makeup cases, they don’t have to be identical.
• A suitable cardboard sheet to make a tube with it.
• Another cardboard sheet to make the mirror supports, you can reuse that of a box.
• Scotch tape
• Pair of scissors
• Glue
• Rule.
• Graphite pencil, eraser.
• Wrapping paper or white paper.
• Colored markers and stickers.

#### Process easy physics experiments

• To build the periscope you need to put two flat mirrors inside a tube, following these steps:
##### Steps to make the mirror support
• Make two equal cardboard supports for the mirrors, which are shaped like a wedge inclined 45Âº with respect to the length of the tube.Â The size of the supports depends on the diameter of the selected mirrors, since these are glued on the wedge, according to this scheme:

• Â Cut out two cardboard rectangles and in each one, mark with the pencil three divisions to make the folds, two of them must have the same length, and the length of the third is calculated with the Pythagorean theorem.Â For example, if the shorter sides are 6 cm, the long side should measure:

dÂ 2Â = (6Â 2Â + 6Â 2Â ) = 72

d = âˆš72 = 8.5 cm.

• Fold the sides that measure the same at right angles, then fold the long side and secure with tape.
• Glue and secure a mirror on the long side of the wedge.
##### Steps to make the periscope tube easy physics experiments
• Take the rectangular cardboard sheet and divide it into four equal rectangles, with the help of the pencil and the ruler.Â The length will be that of the tube, but it must be taken into account that the longer it is, the smaller the image will be.
• Also cut out two windows for the mirrors.
• Fold the cardboard following the marks to make the tube.
• Glue and secure the edges.
• Line the tube with wrapping paper or white paper and decorate it to taste with markers and stickers.

#### What’s going on?

When you look through one of the windows you can see the objects that are above the person’s head, for example you can look at the top of a closet.

#### Explanation easy physics experiments

The light that enters through one of the openings of the periscope is reflected in the first of the inclined mirrors, according to the law of light reflection, according to which the angle of the incident ray is equal to the angle of the reflected ray.

As the mirror is tilted 45 Â°, this causes the horizontally entering rays to now be directed vertically through the tube towards the second mirror.Â And from this they are reflected again at 90Âº towards the eyes of the observer, according to the scheme shown in the figure.

### Observing the magnetic field of magnets

#### Materials

• Plastic lined magnets.
• A sheet of white paper.
• Iron filings (can be obtained from metalworking workshops and toy stores, can also be obtained by cutting steel wool sponges, the kind used to scrub pots and pans)
• An empty salt shaker.
• Latex gloves to handle filings.

#### Process easy physics experiments

• Fill the salt shaker with iron filings.Â It is important that gloves are used to handle the filingsÂ , because sometimes they can dig into the skin or make small annoying cuts on the hands.
• Sprinkle the filings on the white sheet of paper.
• Place the magnet under the blade and move it gently.
• Once the phenomenon has been observed, the magnet must be removed and the filings stored in the salt shaker.Â The magnet is lined with plastic to prevent filings from sticking tightly to it, otherwise it may be cumbersome to remove them later.

#### What’s going on?

Iron filings are oriented along the magnetic field lines produced by the magnet.Â If the magnet moves underneath the paper, the filings above do so as well, describing curious patterns of lines that follow the magnet.

#### Explanation easy physics experimentseasy physics experiments

Magnets have the property of attracting nickel coins, nails, screws, nuts and iron objects in general.Â Magnetism is innate to some substances such as magnetite, an iron oxide, and depends on the configuration of their electrons.

Now, any magnet has north and south magnetic poles, which are inseparable.Â The lines of force of the magnetic field are sharp curves that leave the north pole and go to the south pole, passing without problem through the interior.Â They are denser near the magnet, since the field is more intense there.

## Physics experiments for university (over 18 years)

Physics experiments for college students often require laboratory supplies and almost always involve taking measurements and building tables of data.

The experiments are a bit more elaborate and during the first semesters it is sought that the student corroborates the theoretical models, practices the handling of errors and prepares technical reports.Â Also that he knows the handling of some instruments such as the caliper or caliper and the multimeter to measure electrical magnitudes.

Of course there are also numerous demonstrative experiments to illustrate how physical laws are fulfilled in mechanics and in electricity and magnetism.

### Measurement of electrical resistance

#### Materials

• Assorted fixed electrical resistances.
• A digital or analog multimeter.
• Resistors color code, found in specialized books or on the Internet.

#### Process easy physics experiments

• Use the color code to find the factory value for each resistor.
• Measure the resistance with the multimeter.
• Compare the values â€‹â€‹obtained.

#### What’s going on?

The nominal value of the resistors (the factory one) is indicated by a series of colored bands on the body of the resistors.Â Each band represents a figure and a power of 10, according to the order.

This value may differ slightly from what is measured with the multimeter.Â However, the manufacturer indicates with a metallic colored band, the resistance tolerance margin, which means that its true value is within said margin.

On the other hand, the instrument also has a small margin of error, called an appreciation error, which is usually quite small.Â All measurements made with an instrument must be accompanied by an error in its appreciation.

#### Explanation easy physics experiments

Whenever an object is manufactured, no matter how strict quality controls are carried out, its measurements may differ by a small percentage from the measurements established in the design.Â This applies not only to resistors, but also to countless pieces.

For this reason, manufacturers always indicate a tolerance margin, within which the value in question is located.Â Hence, sometimes the measured values â€‹â€‹differ slightly from the nominal values.

### Determination of the elastic constant of a spring

#### Materials

• Spring or helical spring with a maximum load of 1kg.
• Set of weights.
• Weight holder.
• Chronometer.
• Universal support.
• An object of unknown mass.
• Graph paper.
• Transparent plastic ruler longer than the spring.
• Graphite pencil.
• Computer with graphing software, it can be Excel, Geogebra or another.

#### Process easy physics experiments

• The universal support is available to attach a rod to it, from which the spring is hung vertically by one of its ends.
• The ruler is placed parallel to the spring, completely vertical and adhered to the support, to measure the length of the spring, both its natural length, as well as the length it has when the different masses are hung on it.
• The other end of the spring is used to hang the weights through the weight holder.Â You start with a small mass, for example 50 g, and measure the length of the spring when the system is in equilibrium.Â The measurement is recorded in a table.
• Add more weights to measure the stretchÂ Î”yÂ of the spring when a massÂ mÂ of 100g, 150g, 200g, 250gÂ is hungÂ … The unknown mass is also included, always taking care not to exceed the maximum load that the spring supports , since otherwise it is permanently deformed and the experiment loses validity.
• Once the table is completed, use the software to graph the elongationÂ Î”yÂ of the spring as a function of the massÂ mÂ and make the corresponding curve fit.Â Do not include the unknown mass, since its value is unknown, but the graph obtained, already adjusted, serves to determine its value.

#### What’s going on? easy physics experiments

As larger masses are hung, the spring gets longer and longer.Â Since theÂ graphÂ of the elongationÂ Î”yÂ as a function of the massÂ mÂ is a straight line, the dependence between both variables is linear.

#### Explanation

According toÂ Hooke’s lawÂ , the force exerted by the spring on the hanging mass has magnitude F = kÎ”y, where Î”y is the difference between the elongation of the spring and its natural length.Â This force counteracts the mg weight, therefore:

kÎ”y = mg

Î”y = (g / k) .m

When Î”y is graphed as a function of m, the curve is a line with slope g / k. easy physics experiments

Knowing the value of the slope, which is given by the adjustment made through the software, the elastic constant of the spring can be determined, which represents the force necessary to achieve a unit elongation of the same.Â The units of this constant are newton / m in the International System.

Once you have the value of k, you can immediately know the value of the unknown mass.

### Determination of the static friction coefficient

#### Materials

• Variable incline ramp: usually two planes connected with a hinge.
• Strong cotton yarn.
• A good size nut.
• Piece of wood.
• A press.
• A clear plastic protractor.
• One block of Teflon, one of rubber.
• Teflon sheet and rubber sheet.
• Chronometer.

#### Process easy physics experiments

• Make a plumb bob with the thread and the nut, which will serve to correctly mark the vertical.
• Secure the base of the ramp or inclined plane to the work table using the press.
• Place the wooden block between the base of the ramp and the ramp itself, pushing it inwards, it is possible to tilt the ramp more and more.
• Hang the plumb line from the center of the conveyor and secure this device at the top of the ramp.Â It will be used to measure the angle of inclination of the same, with respect to the vertical indicated by the plumb line.
• Cover the ramp with the Teflon sheet and ensure that it is well adhered.
• Position the Teflon block on top of the Teflon sheet, so that it is at rest.
• Now gently push the wooden block, taking care that the ramp does not move abruptly. Do this until the Teflon block begins to slide. easy physics experiments
• Measure the angle at which the block begins to slide, this is the critical angle for Teflon-Teflon surfaces.Â Repeat these actions at least 10 times, each time noting the critical angle.
• Repeat the previous procedure, but now changing the Teflon block for the rubber one.Â Also determine the critical angle for the Teflon block on rubber 10 times.
• Now replace the Teflon sheet that covers the ramp with the rubber one, and repeat the previous steps again, first for the Teflon block, then for the rubber block.
• Determine the mean value of the critical angle for each case: Teflon-Teflon, rubber-Teflon, rubber-rubber, Teflon-rubber and find the error of the measurement, which depends on the appreciation of the protractor and the standard deviation of the measured data.

#### What’s going on? easy physics experiments

When the ramp is inclined enough, the static friction is no longer enough to keep the block in balance and the block begins to slide downhill.Â The angle at which this happens is called the critical angle and depends on the nature of the surfaces in contact.

#### Explanation easy physics experiments

The maximum static friction force that the block experiences on the ramp is proportional to the normal force, which the ramp exerts on the block.Â The constant of proportionality is called the coefficient of static friction and is denoted as Î¼Â eÂ .

If the free-body diagram is made while the block is in equilibrium, it is shown that the coefficient of static friction is equal to the tangent of the critical angle Î¸Â cÂ , which is the angle of inclination for which the block begins to slide:

Î¼Â eÂ = tg Î¸Â c

Therefore, when determining the angle and finding its tangent, the experimental value of the friction coefficient between certain surfaces is known.

### Capacitor charge easy physics experiments

#### Materials easy physics experiments

• A matrix of connections to mount circuits (Â breadboardÂ ).
• 330 Î¼F discharged capacitor.
• A switch.
• A digital voltmeter.
• Direct voltage source or a 3 V battery.
• Graph paper.
• Transparent ruler and pencil.

#### Process easy physics experiments

• The capacitor should be discharged initially, which can be checked with the voltmeter.Â If any charge remains, its ends are short-circuited by means of a cable and the voltage is checked again to ensure that it is discharged.
• Once the capacitor is discharged, it is placed on the breadboard connecting it in series with the resistor, the switch.
• The source is placed at 3 V and this voltage is verified, connecting the voltmeter in parallel with its terminals.
• The source is connected to the circuit, keeping the switch closed.
• The voltmeter is then connected in parallel with the capacitor to read its voltage from time to time.
• The experiment starts at t = 0 seconds when the switch is opened, then the voltage is measured every 10 to 15 seconds, for about 4 minutes, and is recorded in a table along with its respective time. easy physics experiments
• The approximate time it takes for the capacitor to charge, in seconds, is 5R.C where R is the value of the resistance (in ohms) and C is the capacitor’s capacity (in farads)
• Once the capacitor is charged, the source is turned off.Â The data obtained are plotted on graph paper.

#### What’s going on? easy physics experiments

The initially discharged capacitor charges rapidly at the beginning, but more slowly at the end.

The voltage versus time curve is in the form of an exponential limited by an asymptote, since the voltage is zero at the beginning, and it tends to the value of the battery once the capacitor is charged.

#### Explanation easy physics experiments

From the battery come the positive charges that are deposited on one of the faces of the capacitor, which also acquires a positive charge.Â At first, with the capacitor empty, the charges arrive quickly, but little by little they begin to slow down, since electrostatic repulsion must be considered.

The voltage as a function of time has the form:

Where VÂ oÂ is the voltage of the source used.

The resistance value can be modified, as well as the initial voltage, although the maximum voltage supported by the capacitor must be taken into account, which is indicated on its envelope.Â A higher value resistor causes the capacitor to charge more slowly.

Check Also
Close