Lesson Ideas

5 biology experiments you can do at home

Hands-on experiences are the best way to do science so here are five experiments anyone can complete at home.

Experiment 1: Iso­late DNA from bananas.

DNA is a mol­e­cule with a com­plex struc­ture that stores and pass­es on the ge­net­ic in­for­ma­tion of ev­ery liv­ing or­gan­ism on Earth. This sim­ple method of DNA ex­trac­tion is based on us­ing sur­fac­tants (soap) to de­stroy the lipid lay­ers of ba­nana cells’ mem­branes and nu­clei. Then, sodi­um ions from the ta­ble salt con­vert the DNA mol­e­cules from the de­stroyed cell ma­te­ri­al into a form that eas­i­ly pre­cip­i­tates from the cold iso­propyl al­co­hol.

Experiment 2: Culture your own kom­bucha.

SCO­BY (Sym­bi­ot­ic Cul­ture Of Bac­te­ria and Yeast) is a sym­bi­ot­ic or­gan­ism con­sist­ing of two com­po­nents: bac­te­ria and yeast, as the name sug­gests. The yeast fer­ments sug­ar to form al­co­hol and car­bon diox­ide, and acetic acid bac­te­ria ox­i­dize the al­co­hol and con­vert it into or­gan­ic acids. They grad­u­al­ly cre­ate a com­plex sys­tem that forms a thin film on the liq­uid’s sur­face. As the bac­te­ria and yeast mul­ti­ply, the film thick­ens and ac­quires a char­ac­ter­is­tic jel­ly­fish-like shape. This gives it its name: Medu­somyces gi­se­vii. Be sure to wash the glass con­tain­er thor­ough­ly with a bak­ing soda so­lu­tion and rinse it with boil­ing wa­ter to pre­vent the for­ma­tion of the usu­al mold in­stead of SCO­BY.

Experiment 3: Make pH indicator strips from cabbage.

Red cab­bage con­tains pig­ments known as an­tho­cyanins. An­tho­cyanins can also be found in many fruits, veg­eta­bles, and berries, such as blue­ber­ries, red grapes, red onions, and so on. They change col­ors in ac­cor­dance with the acid­i­ty of their en­vi­ron­ment – a prop­er­ty that can help you de­ter­mine the pH of var­i­ous sub­stances around you! They turn red in acidic medi­ums such as vine­gar, pur­ple in weak­ly acidic and neu­tral medi­ums such as wa­ter, blue in weak­ly ba­sic medi­ums such as a so­lu­tion of bak­ing soda, and green, then yel­low in strong­ly ba­sic so­lu­tions such as drain clean­er.

Experiment 4: Test for vi­ta­min C.

Many fruits and veg­eta­bles con­tain ascor­bic acid, also known as vi­ta­min C. It plays a key func­tion in bi­o­log­i­cal pro­cess­es in the body as a good re­duc­er and con­se­quent­ly a strong an­tiox­i­dant. It helps lim­it the im­pact of var­i­ous free rad­i­cals (ox­i­diz­ing agents that can cause mu­ta­tions and de­struc­tion in cells) on the or­gan­ism. Io­dine can be used to test veg­eta­bles and fruits for ascor­bic acid con­tent. Io­dine is an ox­i­diz­er, so when it re­acts with ascor­bic acid, it is re­duced to col­or­less io­dide ions.

Experiment 5: Ob­tain oxy­gen with the help of a plant.

Here is an in­ter­est­ing and en­ter­tain­ing ex­per­i­ment that lies on the bor­der­line of two sci­ences – chem­istry and bi­ol­o­gy. You can eas­i­ly try it at home and amaze your friends and fam­i­ly. Pho­to­syn­the­sis is a com­plex chem­i­cal process in which light en­er­gy is trans­formed into chem­i­cal bond en­er­gy. More sim­ply, it is a process in which car­bon diox­ide and wa­ter are made into or­gan­ic sub­stances and oxy­gen un­der the in­flu­ence of light.

It is easy to prove the pres­ence of oxy­gen in the test tube. As oxy­gen is a gas that sup­ports com­bus­tion, all you have to do is low­er a smol­der­ing splint or match into the test tube, and it will im­me­di­ate­ly flare up.

Why do we need a so­lu­tion of bak­ing soda? As the car­bon diox­ide in the air dis­solves poor­ly in wa­ter, we can use car­bon­ates or bi­car­bon­ates, which by their na­ture are salts of car­bon­ic acid, to in­crease its con­cen­tra­tion.

Reading extension

You can learn more about fungi, scientific experiments and pH from our article:

How special do you have to be to live in acidic soil?

Check our Lesson Ideas section for more tips for learning science – both in school and at home.

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