Light waves

Revision

2017-12-26T19:27:56+02:00

GSE battery

Use your GSE account of the types name.surname@eduspoo.fi.

You get a prediction of what your score in the actual test could be by taking your score you get from this quiz multiplying it by 3, by dividing this number by 4 and by adding 10 to this number. Convert this score into a grade by using a score-to-grade calculator with max score 31 and pass percent 20.

In media

2017-12-26T19:28:34+02:00

”Puna-aika” paljastaa, kuinka pitkään iho sietää aurinkoa

Aurinkorasvaa pitää levittää kerralla yllättävän paljon. Tunnista oma palamisriskisi ja aika, jonka pystyt olemaan auringossa.

Osa ihmisistä kuulee välähdyksiä ja näkee ääniä – Aistihavaintojen sekoittuminen voi olla luultua yleisempää

Luultua useammilla saattaa olla lievä taipumus synestesiaan eli aistien sekoittumiseen. Neljä faktaa synestesiasta eli aistien sekoittumisesta.

Poika, joka pääsi pois pimeästä

Find out what it means to have xp and how to surviving life with this condition.

Computer tomography

Put your tomography skills to the test! In this article, you will learn to interpret X-ray imaging data.

Ultraviolettisäteily suomalaisille

Missä olosuhteissa Suomessa UV-säteily on voimakkaimmillaan? Mitkä UV-indeksin arvot tarkoittavat haitallista säteilyä? Mikä on korkein Suomessa mitattu UV-indeksin arvo? Entä maailman?

tinyurl.com/uvsuomessa

Valon siroaminen sumeassa nesteessä

Lue Helsingin Sanomien artikkeli ja selvitä, minkälaisella koejärjestelyllä tutkijat päätyvät otsikon johtopäätökseen.

Activities

2017-12-26T19:29:00+02:00

Could your phone harm you?

"Electricity is all around us, all the time. It makes our lives easier, safer, more fun and most of us never think about it. But is there such a thing as too much electricity? Electronic devices emit an electromagnetic field, which is suspected to cause cancer. We read countless sources on this topic to summarize the results of the latest research for you."

Applet - Bending light

Study the bending of a light beam.

Applet - Absorbance

Why do we humans see light? Why cannot we observe ultraviolet? Test yourself!

Applet - Colours

Pair this applet with a handout from below.

Video - What was the Big Bang?

This Kurtzgesagt video explains our contemporary models of the Big Bang.

Video - What is gamma radiation?

This Kurtzgesagt video explains the fundamental properties of gamma radiation.

Video - What is light?

This Kurtzgesagt video explains the fundamental properties of light.

Study notes

2019-03-06T06:49:11+02:00

The human eye grants us the sense of eyesight. They are our tool for perceiving vision rays, also known as light. As the light rays from a light source reflect off of a cat and hit your eyes, these organs give out a message of incoming light though your nerveous system to your brain. Your thinking organ, in turn, interprets this message, and after rehearsing this skill for years and years, you recognize the being before you as a feline creature.

Dim lighting makes it hard to see as there is little light reflected for eyes to catch. Light itself cannot be seen.

A shadow is formed when light is obstructed.

The speed of light, equaling almost 300 000 kilometers per second, is the highest velocity attainable in the universe. According to our modern models, only objects with no mass, such as photons, are capable of moving at this speed, and we massive objects are forever condemned to inferior velocities.

When white light hits a transparent object in an angle, it disperses into the spectrum widely recognized as the rainbow. All phone screens adopt this same principle: by combining different amounts of blue, red and green light, they form all colours imaginable. This method of creating colours is known as the RGB colour system.

Light is actually only a small part of a larger phenomenon known as electromagnetic radiation. It entails many every-day innovations.

These types of radiation, unless in large quantities, are not dangerous to humans:

radio waves, responsible for modern-day communication
microwave radiation, enabling microwave ovens to heat food
infrared radiation, responsible for the Sun's rays' warmth
light, the basis for human vision

These types of radiation, known as ionizing radiation, are know to cause cancer in humans even in small quantities:

ultraviolet or UV radiation, responsible for bronzing skin in summer
X-rays, used in hospitals to study human bones and malformations
gamma rays, the beams of death emitted by supernovae

You should avoid exposing yourself to any and all ionizing radiation. For instance, radiographers and other x-ray personnel in hospitals shield themselves in separate rooms, and even the patient gets a leaden vest to shield their susceptible organs.

The shortest route is not always the fastest. As humans tend to run faster than they swim, it is advisable to pick the route that favours running.

Light can be observed to follow the same principle: when in contact with a denser medium, the light ray is refracted towards the normal of the surface, and when in contact with a sparser medium, the light ray is refracted away from the normal.