Scientific Knowledge:
Before making the experiment I came to the decision that this experiment relates to Hooke’s Law which states that extension is relative to the burden. significance that if you stretch something with a steadily increasing force. so the length will increase steadily excessively. By looking at assorted beginnings I have besides found out that if a mass m on a spring is displaced from the equilibrium place ( x0 = 0 ) to a new place x. Hooke’s jurisprudence states that the spring will exercise a reconstructing force on the mass Fr = -kx. The “-” mark indicates that the way of the spring force is in the way antonym to the way of the supplanting. The value “k” is a changeless for a given spring. but different springs have different “k-values. ” Thus. the force exerted by a spring is variable. specifically the greater distance it is stretched from equilibrium ; the greater is the spring force trying to reconstruct the spring to its equilibrium place. This relationship holds up to a point called the elastic bound. Each spring has its ain value of this bound. If you stretch a spring beyond its bound. so the spring will non return to its original form. but will stay stretched out.
Not all “springy” things obey Hooke’s Law. When a gum elastic set is stretched. the gum elastic will exercise a restoring force. The sum of this force depends on the sum that the gum elastic is stretched. but possibly non in the same simple manner as the spring.
The F=k*x look used to cipher the spring changeless leads to other utilizations of the spring invariable. Once thousand is known. we can utilize the supplanting of the spring to find the force applied to it. Then the spring changeless becomes utile as a force measuring. As such. springs are used to mensurate the weight of objects in common family graduated tables.
Sing a gum elastic set. the spring invariable will depend on the nature of the gum elastic ; some assortments are stiffer than others. It will besides depend on the thickness of the set. Thicker bands will be given to hold higher spring invariables. Besides the length of the set will hold an consequence. For a given thickness. the longer the set. the less force it will bring forth for a given supplanting. This is because there are a greater figure of inter-molecular bonds to take part in the stretching so each bond suffers less strain. Rubber is sensitive to temperature alterations so its spring invariable will alter with temperature. likely increasing as temperature decreases up to a point where it becomes inelastic at really low temperatures.
Prediction
In my experiment I predict that merely the spring will obey Hooke’s Law and the extension will increase straight relative to the force applied to it. as from my scientific cognition I have learnt that if you stretch something with a steadily increasing force so the length will increase steadily excessively. I besides predict that the consequences will give me straight-line graph. This is how I think the graph for the extension of spring will look: –
Apparatus
§ Clamp
§ Ring base
§ Table
§ 3 Springs
§ 3 Rubber sets
§ Meter stick
§ Assorted multitudes
§ Notebook
§ Pen
Diagram
Method
1 ) First set up setup as shown. The clinch should be resting on the tabular array and the ring base must be attached to the clinch. there should be another clinch connected to the ring base where the metre stick can hang down. The metre stick should be parallel to the ring base. To guarantee the consequences are accurate everything must be precise and levelled out.
2 ) Start by attaching a spring onto the clinch next to the metre stick. the spring must be new and one that has non reached its elastic bound. Using the metre stick step the underside of the spring without any weights added and enter your consequences on a clear tabular array.
3 ) Then bit by bit get down adding weights to the spring traveling up in 50g e. g. 50g. 100g. etc. the weights must be firmly hooked on and the extension must be recorded at each phase. taking readings off the metre stick. For accurate consequences it is of import that eyelevel consequences are taken. and consequences should be taken beneath the lowest point the spring is stretching.
4 ) After each phase cheque if the spring retains its original form. if it doesn’t the elastic bound has been reached and at this point you should halt adding the weights. If it does non make its elastic bound continue adding weights until you get up to 500g.
5 ) Once you have reached up to 500g replace the spring with a gum elastic set. Repeat the whole trial once more in precisely the same manner to do it a just trial. Record all your consequences and comparison.
6 ) Repeat the whole trial once more with the spring and gum elastic set at least 3 times. This is so you have accurate and dependable consequences and so you can account for any anomalousnesss or inconsistent consequences.
7 ) Now you must happen out the norm of all your consequences and so work out the spring changeless utilizing this expression: –
K= F/E
Spring changeless = Force/ Extension
This will turn out how accurate your consequences truly are.
Fair trial
In this experiment we are mensurating the extension in centimeter and the force applied will be in gms but will subsequently be changed to Newton’s. To do this experiment just many factors need to be considered. The factors that need to be kept changeless are the tallness at which the spring is hung and the overall sum of weight added to the spring ( 500g ) . The spring and gum elastic set besides have to be trade name new and fresh. The factor that needs to be changed is the sum of force added to the spring and gum elastic set at one clip. This will be added utilizing weights and will bit by bit be increasing. I besides need to do certain that the work surface is wholly flat and non slanted. All consequences should be taken at eyelevel and there should be no bill of exchange or light zephyr impacting the consequences so all doors and Windowss must be closed.
Safety
While making the experiment it is of import to see facet of safety. To guarantee the experiment is carried out in a safe manner I have to foremost bind back long hair and lose vesture to forestall distractions and intervention and I have to unclutter the work surface so that there is adequate infinite to make the experiment. A stool should besides be placed beneath the spring/rubber set in instance they brake. I need to be concentrating on the experiment at all times and bags. books. etc demand to be moved out of the manner.
Decision
By making the experiment I determined that merely the spring and gum elastic set obeyed hook’s jurisprudence. Hooke’s jurisprudence can besides be expressed as a expression:
Force = a changeless ten extension
F = ke
My anticipation was right and from my graph you can see an increasing incline. which shows that the extension increased proportionately to the sum of force applied to it. This is because harmonizing to Hooke’s jurisprudence if you double the burden the extension is doubled excessively. This jurisprudence is merely true if the elastic bound has non been reached. In my experiment the spring and gum elastic set did non make their elastic bound. hence Hooke’s jurisprudence could be applied. this is because the elastic bounds of the two objects were much higher and they could defy the force that was applied.
My predicted graph was besides similar to the graph I drew from my consequences. by doing a line of best tantrum I was able to hold a straight-line graph. In my consequences I besides included the spring invariable. this besides turned out as expected.
Each clip I added a 50 g weight ; the spring stretched a twosome of centimeters. The spring had a higher extension than the gum elastic set ; this may be because of the natural snap of both stuffs or it could depend on the stiffness. thickness or quality of the spring/rubber set.
The gum elastic set nevertheless. did non obey Hooke’s jurisprudence. From my consequences you can see that the consequences for the gum elastic set produce a curve graph. I have notice that the gum elastic set did obey Hooke’s jurisprudence for really little multitudes. The curve can be due to the fact that gum elastic sets can’t infinitely be exerted. because they have a maximal effort and so when the effort force becomes truly high the gum elastic set loses its belongings of following Hooke’s jurisprudence. Rubber sets are non truly elastic. but merely stretchy. When a gum elastic set stretches it gets thinner and longer. but something else happens every bit good. The gum elastic set gets warmer as it stretches. The gum elastic set is unable to make every bit much work because it loses energy.
Evaluation
I think the experiment went good because the consequences agreed with my anticipation. However there were a few anomalousnesss. the most obvious was the consequence taken for the spring without any weights added to it. The consequence was rather low compared to the others and even went below the gum elastic consequence. This may hold occurred because of a deficiency of concentration while entering the consequences or I may non hold taken an eyelevel recording. Besides my consequences may non hold been that accurate. if we could utilize electronic engineering the consequences would be a batch more accurate and dependable. whereas by making it manually. errors can easy be made.
Although my anticipation was proved I still don’t believe I had adequate consequences. If I had more clip I would hold taken at least 5 sets of consequences instead than 3. this would give me a batch more consequences to work with and I could hold made a better decision.
The method I followed was a good manner to transport out the experiment but can be improved. First another swayer needs to be used underneath the spring/rubber set while its stretching to enter the consequences more accurately and the weights need to be removed on a regular basis to look into if the spring/rubber set goes back to its original form and whether or non it has reached its elastic bound. Besides we should hold looked at more stretchable stuffs to compare them with each other. This would hold given a wider assortment of consequences.
To widen the experiment I could look at the elastic bound of different stretchable stuffs and add weights until the spring/rubber set does non travel back to its original form. by making this I will be able to compare how much weight the different stuffs can defy and what factors affect their strength by looking closely at the inter-molecular bonds within their constructions.
